HOST LISTS AND KEYS FOR EACH PLANT GENUS

(in alphabetical order)

Cas-Cha

Cascabela

Casearia

Cassia

Cassinia

Cassytha

Castalia

Castanea

Castanopsis

Castanospermum

Castelleja

Casuarina

Catabrosa

Catalpa

Catamixis

Catananche

Catapodium

Catharanthus

Catharinea

Catimbium

Cattleya

Caucalis

Cayaponia

Cayratia

Ceanothus

Cecropia

Cedrela

Cedrus

Ceiba

Celastrus

Celmisia

Celosia

Celtis

Cenchrus

Cenolophium

Centaurea

Centaurium

Centotheca

Centranthus

Centrosema

Cephalanthera

Cephalanthus

Cephalaria

Cephalanoplos

Cephalotaxus

Cerastium

Cerasus

Ceratocarpus

Ceratocephalus

Ceratochloa

Ceratoides

Ceratonia

Ceratophyllum

Ceratostigma

Ceratotheca

Cercidiphyllum

Cercis

Cercocarpus

Cereus

Cerinthe

Cerinthodes

Ceropegia

Ceropteris

Cestrum

Ceterach

Chaenactis

Chaenomeles

Chaerophyllum

Chaetochloa

Chaetotropis

Chalcas

Chamaebatia

Chamaebatiaria

Chamaecrista

Chamaecyparis

Chamaecytisus

Chamaedaphne

Chamaedorea

Chamaegeron

Chamaemelum

Chamaenerion

Chamaerhodos

Chamaerops

Chamaespartium

Chamaesyce

Chamelaucium

Chamissoa

Chamomilla

Changium

Chaptalia

Chardinia

Cascabela	Apocynaceae
Cascabela thevetia	Aphis gossypii, spiraecola; Myzus persicae

Use key to polyphagous aphids.

Casearia	Salicaceae
Casearia arborea	Aphis (Toxoptera) aurantii
C. decandra	Aphis spiraecola
C. hirsuta	Aphis (Toxoptera) aurantii
C. sylvestris	Aphis (Toxoptera) aurantii
Casearia sp	Aphis craccivora

(use key to polyphagous aphids)

Cassia	Fabaceae
Cassia abbreviata	Myzus persicae
C. absus = Chamaecrista absus
C. alata = Senna alata
C. aphylla = Senna aphylla
C. australis (?)	Aphis gossypii; Aulacorthum solani; Myzus persicae
C. benitoensis = Senna benitoensis
C. bicapsularis = Senna bicapsularis
C. corymbosa = Senna corymbosa
C. didymobotrya = Senna didymobotrya
C. fistula	Aphis craccivora, fabae, odinae; Myzus persicae
C. floribunda (?)	Aphis craccivora, fabae, gossypii
C. glauca = Senna sulfurea
C. goratensis = Senna singueana
C. hirsuta = Senna hirsuta
C. hoffmansegi (?)
C. javanica	Aphis craccivora
C. laevigata = Senna septemtrionalis
C. leiophylla = Senna leiophylla	Aphis gossypii; Myzus persicae
C. leptocarpa = Senna hirsuta var. leptocarpa
C. mimosoides = Chamaecrista mimosoides
C. nomane = Chamaecrista nomane
C. obtusifolia = Senna obtusifolia
C. occidentalis = Senna occidentalis
C. siamea = Senna siamea
C. sophera = Senna sophera
C. sturtii	Myzus persicae
C. surattensis = Senna surattensis
C. tomentosa = Senna hirsuta
C. tora = Senna tora
Cassia sp. (African)	Sitobion burundiense

Key to apterae on Cassia:-

–	SIPH black with polygonal reticulation on distal 0.17-0.25 of length. ANT PT/BASE 5.1-6.6. First tarsal segments all with 4 hairs	…..Sitobion burundiense
–	SIPH if black then without distal reticulation, and other characters do not apply	…..go to key to polyphagous aphids

Cassinia	Asteraceae
Cassinia quinquefaria	Aphis spiraecola
Cassinia sp.	Macrosiphum euphorbiae

(use key to polyphagous aphids)

Cassytha	Lauraceae
Cassytha filiformis	Sinomegoura citricola

Castalia see Nymphaea

Nymphaeaceae

Castanea	Chestnuts Fagaceae
C. ashei	Longistigma caryae; Patchia virginiana
C. bungeana	Tuberculatus castanocallis, cereus, ceroerythros, kuricola,
	margituberculatus
C. crenata	Japanese Chestnut
	Cervaphis quercus; Eutrichosiphum pasaniae, pallidum;
	Greenidea kuwanai, magna, pallidipes;
	[Kurisakia onigurumii]; Lachnus tropicalis;
	[Macrosiphum kuricola Matsumura 1917, nomen dubium];
	Mollitrichosiphon tenuicorpus; Myzocallis castanicola;
	Myzocallis castanicola; Phylloxera castaneivora; Pseudomegoura magnoliae; [Nippolachnus piri];
	Tuberculatus capitatus ssp. intermedius, kuricola
C. dentata	American Chestnut
	Myzocallis castaneae, castaneoides, castanicola;
	Patchia virginiana; Phylloxera castaneae
C. formosana	Eutrichosiphum tattakanum
C. henryi	Lachnus tropicalis; Tuberculatus kuricola
C. mollissima	[Aphis odinae]; Cervaphis quercus; Greenidea kuwanai;
	Lachnus [quercihabitans], tropicalis;
	[Metanipponaphis cuspidatae];
	Phylloxera castaneae, castaneivora;
	Tuberculatus castanocallis, kuricola, margituberculatus
C. nana	Myzocallis castaneoides, nanae, tissoti
C. pubinervis	Cervaphis quercus; Tuberculatus kuricola
C. pumila	Myzocallis castanicola; Patchia virginiana;
	Phylloxera castaneae; Tuberculatus annulatus
C. sativa	Sweet Chestnut
	[Aphis gossypii]; [Aulacorthum solani];
	Lachnus longirostris, roboris, tropicalis;
	Myzocallis castaneoides, castanicola, castanicola spp.
	leclanti, [komareki];
	Phylloxera castaneae, [spinifera]; Thelaxes suberi;
	Tuberculatus annulatus, kuricola
C. seguinii	Tuberculatus castanocallis, ceroerythros
Castanea sp.	[Mollitrichosiphum nigrum]

Key to aphids feeding on Castanea:-

1	Antennae 3-segmented (small insect, body pyriform, broadest anteriorly	…..2
–	Antennae 5- or 6-segmented	…..3
2	Many dorsal tubercles present on head, thorax and ABD TERG 1-6, decreasing in size and number posteriorly	…..Phylloxera castaneivora
–	Only 4 dorsal tubercles present, confined to head	…..Phylloxera castaneae
3	SIPH tubular, several times longer than wide	…..4
–	SIPH truncate or broad, hairy cones	…..12
4	Body of aptera with very long, branched, hair-bearing marginal processes (fig. 92A)	…..Cervaphis quercus
–	Body of aptera without hair-bearing processes	…..5
5	SIPH without hairs. Antennal tubercles well-developed, approx. parallel-sided in dorsal view (as in fig. 42J)	…..Pseudomegoura magnoliae
–	SIPH with numerous long fine hairs. Antennal tubercles undeveloped	…..6
6	SIPH of aptera reticulated either basally or over much of length. Cauda with a distinct median conical papilla (as in fig. 92B)	…..7
–	SIPH of aptera without any reticulation. Cauda without a median papilla	…..9
7	SIPH of aptera with a spinulose reticulation over the entire length, except for a small distal part with only spinules . BL 2.4-3.4 mm	…..Greenidea magna*
–	SIPH with reticulation restricted to basal zone. BL 1.3-2.6 mm	…..8
8	BL 1.3-2.2 mm. Head and legs mainly pale	…..Greenidea (Trichosiphum) pallidipes*
–	BL 2.0-3.0 mm. Head and legs mainly dark	…..Greenidea (Trichosiphum) kuwanai
9	SIPH of aptera more than 0.7 ×BL. Hind tibiae with transverse stridulatory ridges (as in fig. 27A)	…..Mollitrichosiphon tenuicorpus
–	SIPH of aptera less than 0.7 × BL. Hind tibiae without stridulatory ridges	…..10
10	Dorsum of aptera with numerous irregular transverse rows of minute spinules	…..Eutrichosiphum pasaniae
–	Dorsum of aptera without spinules, or with spinules only on marginal areas of thorax and ABD TERG 1-2	…..11
11	Antennae of aptera 5- or 6-segmented, of alata 6-segmented. Dorsal abdomen with ill-defined dark pigmentation leaving pale central area on ABD TERG 1-3. SIPH of aptera usually dusky/dark distally	…..Eutrichosiphum tattakanum
–	Antennae 5-segmented in alatae as well as apterae. SIPH of aptera evenly pale, paler than the uniformly smoky dorsal abdomen	…..Eutrichosiphum pallidum*
12	ANT PT/BASE about 1.0 or more. Anal plate divided by a median cleft into 2 lobes	…..13
–	ANT PT/BASE 0.5 or less. Anal plate not bi-lobed	…..26
13	Cauda triangular, apically pointed, without a constriction (fig. 35A). Body and appendages almost entirely brown-black	…..Patchia virginiana
–	Cauda with a constriction and a terminal knob. Body and appendages mainly pale, sometimes with dark markings	…..14
14	14 Head and pronotum with a longitudinal dark spinal stripe, and ABD TERG 1-7 each with paired dark dorsal spinal as well as marginal sclerites (fig. 35E). (Wings not maculate)	…..15

–	Head and pronotum without a spinal longitudinal stripe. If ABD TERG 1-7 have a complete set of paired dark dorsal sclerites then wings are strongly maculate	…..16
15	R IV with 4-10 accessory hairs. First tarsal segments with 5-6 ventral hairs. Embryos with long hairs (55-70 μm) on ABD TERG 2	…..Myzocallis castanicola (s. str.)
–	R IV with 11-18 accessory hairs. First tarsal segments with 6-8 (usually 7) ventral hairs. Embryos with hairs on ABD TERG 2 shorter (27-41 μm)	…..Myzocallis castanicola ssp. leclanti
16	Tibiae mainly brown to black, or at least brown on basal half. ANT PT/BASE more than 2.0	…..17
–	Tibiae mainly pale, sometimes dark apically. ANT PT/BASE less than 2.0	…..20
17	Anterior frontal hairs of head long and finely pointed, 2 or more × basal diameter of ANT III (fig.35B)	…..18
–	Anterior frontal hairs less than 2 × basal diameter of ANT III, and sometimes with capitate apices (figs 35C, D)	…..19
18	Tibiae and ANT III-VI uniformly black	…..Myzocallis castaneae
–	Tibiae dark at base but with paler middle region. ANT IV, V and BASE VI each pale at base and dark at apex	…..Myzocallistissoti
19	Anterior frontal hairs 7-15 um long, shorter than basal diameter of ANT III, and capitate	…..Myzocallis nanae
–	Anterior frontal hairs 30-38 um, longer than basal diameter of ANT III, pointed or slightly capitate (fig. 35D). ANT III-VI and tibiae often completely dark	…..Myzocallis castaneoides

20	Forewings with pigment extending between veins, or with veins at least heavily bordered with pigment. Abdomen broad and often with large dark marginal processes	…..21
–	Forewings not pigmented between veins. Abdomen with or without smaller, pale marginal processes	…..25

21	ANT III with 4-6 hairs, 1-2 × longer than basal diameter of segment	…..Tuberculatus margituberculatus
–	ANT III with 7 or more hairs, including anteriorly directed long ones that are much more than 2 × basal diameter of the segment	…..22

22	ANT III with 16 or more hairs. Marginal processes each with 1-6 transparent noduli (fig. 35F)	…..23
–	ANT III with less than 15 hairs. Marginal processes without any transparent noduli	…..24
23	Head with 20-22 dorsal hairs. Dorsal body hairs thick, and spinal hairs on posterior tergites arise from tubercular bases	…..Tuberculatus ceroerythros*
–	Head with more than 40 dorsal hairs. Dorsal body hairs thin and spinal hairs on posterior tergites not arising from tubercular bases	…..Tuberculatus cereus
24	ABD TERG 2 and 3 each with a pair of quadrate spinal processes, as long as or longer than their basal widths (fig. 35G). Distal parts of hind femora dark	…..Tuberculatus castanocallis
–	Spinal processes on ABD TERG 2 and 3 if developed then rounded, and shorter than their basal widths (fig. 35H). Hind femora pale	…..Tuberculatus kuricola

25	Spinal processes on ABD TERG 1-3 all similarly developed, finger-like, longer than their basal widths (fig.35I). Anteriorly directed hairs on front of head and ANT I-III long and capitate. SIPH pale	…..Tuberculatus capitatus (ssp. intermedius)
–	Spinal processes only ever well-developed on ABD TERG 3, and then conical, shorter than their basal widths. Hairs on front of head and ANT I-III short or very short, and pointed. SIPH black except at bases	…..Tuberculatus annulatus
26	BL less than 2 mm. Antennae 5-segmented. Cauda knobbed	…..Thelaxes suberi
–	BL more than 2.5 mm. Antennae 6-segmented. Cauda broadly rounded	…..27

27	ABD TERG 8 unmarked or with only irregular pigment spots. Alata with pterostigma extending around tip of forewing	…..Longistigma caryae
–	ABD TERG 8 with a thin transverse band. Alata with pigmented (maculate) forewings and normal pterostigma	…..28
28	Hind tibia with some of more distal hairs on ventral side very long and fine-pointed, at least 2-3 × longer than neighbouring short hairs (fig. 93D). Mesosternal processes always absent or weakly developed. (SIPH cones small and often pale)	…..Lachnus longirostris
–	Hind tibia with hairs on ventral side often longer and finer distally, but not with some hairs 2-3 × longer than others. Mesosternum of summer aptera usually with a pair of mammariform or papilliform processes. (SIPH cones usually large and pigmented)	…..29

29	ANT/PT BASE 0.40-0.68, usually more than 0.5. Alata with forewing pigmented to base	…..Lachnus tropicalis
–	ANT/PT BASE 0.3-0.5. Alata with clear area at base of forewing	…..Lachnus roboris

Castanopsis(= Shiia)	Fagaceae
C. acuminatissima	Eutrichosiphum pasaniae, pullum;
	Greenidea [castanopsidis], magna;
	Nipponaphis javanica
C. argentea	Eutrichosiphum pasaniae, pullum;
	Greenidea magna, pallidipes;
	Nipponaphis brevipilosa
C. calathiformis	Mollitrichosiphum tenuicorpus
C. carlesii	Eutrichosiphum pasaniae; Metanipponaphis ?echinata;
	Mollitrichosiphum tenuicorpus
C. cuspidata	Allotrichosiphum kashicola;
	Eutrichosiphum pasaniae, shiicola, sinense;
	Greenidea [kuwanai], okajimai;
	Lachnus tropicalis (or shiicola?);
	Lithoaphis shiiae; Metanipponaphis cuspidatae, shiicola;
	Mollitrichosiphum tenuicorpus; Neonipponaphis shiiae;
	[Nipponaphis distyliicola]; Reticulaphis shiiae
C. eyrei	Neonipponaphis pustulosa
C. fabri	Eutrichosiphum pasaniae;
	Mollitrichosiphum tenuicorpus, [nigrofasciatum]
C. fargesii	[Aphis (Toxoptera) citricidus];
	Eutrichosiphum [pseudopasaniae]
C. ferox	Eutrichosiphum sinense; Mollitrichosiphon tenuicorpus
C. formosana	Eutrichosiphum tattakanum; Mollitrichosiphon tenuicorpus
C. hainanensis	Mesotrichosiphum pentaiarticulatum
C. hickelii	[Allotrichosiphum castanopse (=Eutrichosiphum sinense?)]
C. hystrix	Metanipponaphis echinata; Mollitrichosiphon tenuicorpus
C. indica	Eutrichosiphum pasaniae, [pseudopasaniae], sinense;
	Lachnus acutihirsutus
C. javanica	Eutrichosiphum nigrum, pasaniae, sinense;
	Greenidea magna, pallidipes; Nipponaphis multisetosa
C. sclerophylla	[Eutrichosiphum sclerophyllum (= shiicola?), arunachali ssp.
	jianglense];
	Lachnus tropicalis; Metanipponaphis lithocarpicola;
	Mollitrichosiphum tenuicorpus; [Tuberculatus castanocallis]
C. sieboldii	Greenidea okajimai;
	Metanipponaphis cuspidatae, rotunda, shiicola;
	Neonipponaphis shiiae; Nipponaphis monzeni
C. subacuminata	Eutrichosiphum pasaniae; Mollitrichosiphum tenuicorpus
C. submacula	Eutrichosiphum pasaniae
C. subsericea	Eutrichosiphum pasaniae
C. tribuloides	Eutrichosiphum pasaniae, [pseudopasaniae];
	Metanipponaphis assamensis
Castanopsis sp(p).	Eutrichosiphum dubium, [flavum], kumaoni, [neoalnicola],
	[neotattakanum], russellae;
	Greenidea [kunmingensis], sikkimensis;
	Lachnus [quercihabitans], shiicola, sorini;
	Metanipponaphis rotunda; Mollitrichosiphum niitakaensis;
	Parathoracaphis manipurensis;
	Schizoneuraphis querciphaga

Key to aphids feeding on Castanopsis:-

1	Aptera with head, thorax and ABD TERG 1 fused as prosoma. Legs and antennae much reduced, often concealed beneath body. SIPH small or absent. Antennae of alata with narrow ring-like sensoria	…..2
–	Aptera of normal aphid form with well-developed legs and antennae. SIPH evident, conical or tubular. Antennae of alata with circular or oval sensoria	…..12
2	Aptera without SIPH	…..3
–	Aptera with SIPH usually present as small pores or cones	…..4
3	Tarsi and claws rudimentary; dorsum strongly reticulated (fig.36A)	…..Reticulaphis shiiae
–	Two-segmented tarsi and claws developed; dorsum without reticulation	…..Parathoracaphis manipurensis
4	Dorsal cuticle of prosoma mainly smooth except for areolation, pustules only present around thoracic spiracles. Prosomal hairs long and thick with somewhat tuberculate bases. ABD TERG 8 with 4 hairs	…..Schizoneuraphis querciphaga
–	Dorsal cuticle of prosoma ornamented with numerous raised pustules or translucent rounded or curved areas (figs 36B – E). Prosomal hairs short or if long then fine. ABD TERG 8 with 2-10 hairs	…..5
5	Abdominal plate (ABD TERG 2-7) distinctly separate from prosoma (e.g. fig. 36B). ABD TERG 8 with 4-8 hairs	…..6
–	Abdominal plate fused with or not distinctly separate fom prosoma, at least in median area (fig. 36C). ABD TERG 8 with 2-10 hairs	…..7
6	Pustules on prosoma irregularly-shaped, angular, especially on marginal areas (Fig. 36A, B). Spinal and marginal hairs of prosoma longer, but not thicker or stiffer, than scattered dorsal hairs. ABD TERG 8 with 4-6 hairs	….. Neonipponaphis shiiae
–	Pustules on prosoma smaller and oval or rounded. Spinal and submarginal hairs of prosoma distinctly thicker and stiffer as well as longer than scattered dorsal hairs. ABD TERG 8 with 6-8 hairs	…..Neonipponaphis pustulosus*
7	Prosoma ornamented with blunt conical nodules, often longer than their basal widths (fig. 91A). Prosomal hairs very long and very fine	…..Nipponaphis monzeni
–	Prosoma if pustulate then the pustules are low, all or mostly shorter than their basal widths (fig. 36). Prosomal hairs long or short	…..8
8	ABD TERG 8 with 2-4 hairs. Prosoma dorsally ornamented with densely packed, evenly distributed, rather uniform-sized, circular or oval pustules (fig. 36C)	…..Metanipponaphis spp.

–	ABD TERG 8 with 4-6 hairs. Prosoma with polygonal, angular or irregular dorsal ornamentation; if pustulate, then the pustules are of irregular size and shape	…..9
9	Prosoma strongly convex dorsally, with irregular translucent branched or curved ornament-ation (fig. 36D). ABD TERG 8 with 6 hairs	…..Lithoaphis shiiae
–	Prosoma somewhat flattened dorsally, with variable pustulate or polygonal ornamentation (e.g. fig. 36E). ABD TERG 8 with 4 hairs	…..10

10	Prosomal hairs only 10-20 µm long, and those on ABD TERG 8 only 35-40 µm long	…..Nipponaphis brevipilosa
–	Prosomal hairs 40-125 µm long, and those on ABD TERG 8 65-160 µm long	…..11
11	Prosoma with only 6-7 hairs (2-3 spinal, 4 marginal) on each thoracic tergite, and 4 hairs (2 spinal, 2 marginal) on ABD TERG 1	…..Nipponaphis javanica
–	Prosomal hairs much more numerous; 30-70 per tergite	…..Nipponaphis multisetosa
12	SIPH tubular, bearing numerous long hairs	…..13
–	SIPH as shallow hairy cones	…..27
13	SIPH of aptera with pale reticulation either basally or over much of length. Cauda with a distinct median conical papilla (as in fig. 92B)	…..14
–	SIPH of aptera without any pale reticulation. Cauda without a median papilla	…..17
14	SIPH of aptera with a spinulose reticulation over the entire length, except for a small distal part with spinules only. BL 2.4-3.4 mm	…..Greenidea magna*
–	SIPH with reticulation restricted to basal zone. BL 1.3-2.8 mm	…..15
15	Ventral abdomen with spinulosity confined to marginal areas	…..Greenidea pallidipes*
–	Mid-ventral area of abdomen evenly spinulose	…..16
16	R IV+V 1.3-1.8 × longer than HT II	…..Greenidea okajimai
–	R IV+V 1.85-2.5 × longer than HT II	…..Greenidea sikkimensis*
17	Hind tibiae with transverse (stridulatory?) ridges (e.g. fig. 27A )	…..18
–	Hind tibiae without transverse ridges	…..19
18	Antennae 5- or 6-segmented. SIPH of aptera less than 0.5 × BL	…..Mollitrichosiphum niitakaensis
–	Antennae 6-segmented. SIPH of aptera 0.65 or more × BL	…..Mollitrichosiphum tenuicorpus
19	Longest hairs on antennae and dorsum distinctly capitate (fig. 92C)	…..Allotrichosiphum kashicola
–	Hairs on antennae and dorsum with pointed, blunt, expanded or bifurcate apices, but never capitate	…..20
20	Dorsum of aptera without spinules, or with spinules restricted to marginal areas	…..21
–	Dorsum of aptera with numerous irregular transverse rows of minute spinules	…..26
21	Femora and basal parts of tibiae as dark as or darker than body. ANT PT/BASE less than 1. First tarsal segments with 5 hairs	…..22
–	Femora and tibiae paler than body. ANT PT/BASE more than 1. First tarsal segments with 7 hairs	…..23
22	R IV+V 1.7-2.0× HT II, which is 0.10-0.11 mm long. Mid-dorsal abdominal hairs much shorter than marginal hairs	…..Mesotrichosiphum pentaiarticulatum*
–	R IV+V 2.1-2.4× HT II, which is 0.08-0.09 mm long. Mid-dorsal abdominal hairs similar in length to marginal hairs	….. Eutrichosiphum nigrum*
23	R IV+V 3.1-3.6× HT II	…..Eutrichosiphum russellae
–	R IV+V 1.9-2.8× HT II	…..24
24	BL 1.2-1.7 mm. SIPH 0.19-0.22 × BL	…..Eutrichosiphum pullum*
–	BL 1.9-2.9 mm. SIPH 0.25-0.35 × BL	…..25
25	Dorsal abdomen with extensive (but variably pigmented) sclerotisation. Marginal areas and venter of abdomen finely spiculose	…..Eutrichosiphum tattakanum
–	Dorsal abdomen unsclerotised. Marginal areas an venter of abdomen smooth	…..Eutrichosiphum kumaoni*

26	Aptera with R IV+V 1.5-1.7 × HT II, and SIPH longer than maximum body width. SIPH of alata more than 1.5 × ANT III	…..Eutrichosiphum shiicola
–	Aptera with R IV+V 1.8-2.6 × HT II, and SIPH shorter than maximum body width. SIPH of alata less than 1.5 × ANT III	…..27
27	Dorsum of aptera pale, SIPH mostly dark but pale at base, and at least 0.7 × maximum body width	…..Eutrichosiphum sinense
–	Dorsum of aptera pale or dark brown, SIPH wholly dark and 0.5-0.6 × maximum body width	…..Eutrichosiphum pasaniae
28	Abdomen bearing a large rounded tubercle on ABD TERG 4, its base about as broad as that of SIPH cones (and another much smaller and flatter tubercle on ABD TERG 5)	…..Lachnus sorini
–	Abdomen without a large tubercle on ABD TERG 4	…..29
29	Longest hairs on ANT III 2.0-2.25 × basal diameter of segment. SIPH on large hairy cones which are about 3.4- 5.3 × longer than the diameter of the siphuncular pore. R IV+V 1.1-1.2 × HT II	…..Lachnus shiicola
–	Longest hairs on ANT III 0.67-1.4 × basal diameter of segment. SIPH on small hairy cones which are 2-3 × longer than the diameter of the siphuncular pore. R IV+V 0.74-1.05 × HT II	…..30
30	Longest hairs on ANT III 0.67-0.85 × basal diameter of segment. R IV+V 0.74-0.82 × HT II. Forewing of alata with large clear areas between media and cubitus veins, and between Cu1b and base of wing	…..Lachnus acutihirsutus
–	Longest hairs on ANT III 0.9-1.4 × basal diameter of segment. R IV+V 0.9-1.05 × HT II. Forewing of alata mostly pigmented with only small clear areas	…..Lachnus tropicalis

Castanospermum	Fabaceae
Castanospermum australe	Australian Chestnut
	Betacallis querciphaga; Mollitrichosiphon tenuicorpus

Castilleja	Orobanchaceae
Castilleja affinis ssp. neglecta	Nasonovia castelleiae
C. coccinia	Nasonovia castelleiae
C. exserta (see Orthocarpus)	[Macrosiphum orthocarpus]
C. foliolosa	Brachycaudus helichrysi
C. linariifolia	Nearctaphis hottesi
C. miniata	Nasonovia castelleiae
C. neglecta = C. affinis ssp. neglecta
C. occidentalis	Nasonovia sampsoni
C. pavlovii	Nasonovia castelleiae
C. pruinosa	Nasonovia sampsoni
C. raupii	Nasonovia castelleiae
C. wightii	Nasonovia sampsoni; Macrosiphum euphorbiae
Castilleja spp.	Aphis sp. (Montana, USA; BMNH collection, leg. D Hille
	Ris Lambers);
	Cedoaphis incognita (as Aphis chipetae Hottes);
	[Macrosiphum sp.]; Nearctaphis bakeri, kachena

Key to aphids on Castilleja:-

1	ANT (of apt.) with secondary rhinaria	…..2
–	ANT without secondary rhinaria	…..5
2	Head spiculose. SIPH 3-4 × cauda, which is shorter than its basal width and bears more than 20 hairs	…..Cedoaphis incognita
–	Head not spiculose. SIPH 0.8-2.2 × cauda which is much longer than its basal width and bears 5-12 hairs	…..3
3	SIPH 0.25-0.35 × BL, with a subapical zone of polygonal reticulation	…..Macrosiphum euphorbiae
–	SIPH 0.06-0.22 × BL, without any polygonal reticulation	…..4
4	R IV+V 1.7-2.5 × HT II, with 20-25 accessory hairs. SIPH only weakly imbricated, 1.5-2.1 × cauda	…..Nasonovia sampsoni
–	R IV+V 1.0-1.5 × HT II, with 6-10 accessory hairs. SIPH strongly imbricated, with rows of spinules on the imbrications; 0.8-1.3 × cauda	….. Nasonovia castelleiae
5	SIPH smooth, head smooth, cauda helmet-shaped	…..Brachycaudus helichrysi
–	SIPH imbricated or with rows of spinules. If head smooth then cauda tongue-shaped	…..6
6	SIPH imbricated and at least 0.1 × BL. Head smooth. ABD TERG 1 and 7 with marginal tubercles (MTu), which are absent from or only sporadically present on 2-5	…..Aphis sp. (Montana, USA; BMNH collection, leg. D Hille Ris Lambers)
–	SIPH spinulose and less than 0.09 × BL. Head spiculose. ABD TERG 2-5 with MTu, 1 and 7 without MTu	…..7
7	Second tarsal segments smooth or almost smooth	…..Nearctaphis kachena
–	Second tarsal segments with distinct imbrication	…..8
8	Dorsal abdominal hairs arising from dark scleroites, and ABD TERG 7 and 8 with dark cross-bands. R IV+V usually shorter than ANT V	…..Nearctaphis bakeri
–	Dorsal abdomen without dark markings. R IV+V usually longer than ANT V	…..Nearctaphis hottesi

Casuarina	Casuarinaceae
Casuarina equisetifolia	Aphis gossypii; [Lachnus ?tropicalis];
	Myzus persicae
C. huegeliana	Aphis gossypii; Myzus persicae
C. torulosa	Aphis (Toxoptera) aurantii

Use key to polyphagous aphids .

Catabrosa	Poaceae
Catabrosa aquatica	Cavariella aquatica; Rhopalosiphum padi; Sipha glyceriae

Use key to apterae of grass-feeding aphids under Digitaria.

Catalpa	Bignoniaceae
Catalpa bignonioides	Aphis aurantii, catalpae, gossypii; Myzus persicae
C. hybrida	Aphis aurantii, gossypii; Myzus persicae
C. ovata	Aphis gossypii
C. speciosa	Aphis catalpae, [frangulae], gossypii
Catalpa sp.	Aphis fabae, nerii, spiraecola; Aulacorthum solani;
	Macrosiphum euphorbiae; Myzus ornatus

Key to species on Catalpa:-

1	Antennal tubercles well-developed	…..go to key to polyphagous aphids
–	Antennal tubercles weakly developed	…..2
2	SIPH and cauda both very dark	…..go to key to polyphagous aphids
–	Cauda pale or dusky, SIPH pale, dusky or dark	…..3
3	Alata usually without any secondary rhinaria on ANT IV (rarely 1-2). Aptera with SIPH uniformly dusky to dark, and 1.3-2.5 × cauda	…..Aphis gossypii
–	Alata with 1-4 rhinaria on ANT IV. Aptera with SIPH usually paler towards base, and 1.10-1.35 × cauda	…..Aphis catalpae

Catamixis	Asteraceae
Catamixis baccharoides	[Acyrthosiphon rubi]

Catananche	Asteraceae
Catananche caerulea	Protaphis terricola

Catapodium	Poaceae
Catapodium marinum	Sipha glyceriae

Catharanthus	Apocynaceae
Catharanthus roseus	Aphis fabae, gossypii, spiraecola;
	Macrosiphum euphorbiae, [stellariae];
	Myzus [certus], ornatus, persicae;
	[Nasonovia ribisnigri]; Rhopalosiphoninus staphyleae;
	[Rhopalosiphum nymphaeae]

Use key to polyphagous aphids.

Catharinea see Atrichum

Polytrichaceae

Catimbium see Alpinia

Zingiberaceae

Cattleya	Orchidaceae
Cattleya harrisoniana	Cerataphis orchidearum
C. lobata	Sitobion luteum
C. lueddemanniana	Aphis (Toxoptera) aurantii
C. speciosissima = C. lueddemanniana
Cattleya spp.	Sitobion anselliae, luteum

Use key to apterae of orchid-feeding aphids under Cymbidium.

Catunaregam	Rubiaceae
Catunaregam spinosa	Aphis (Toxoptera) aurantii; Myzus persicae
C. tomentosa	Aphis spiraecola

Use key to polyphagous aphids.

Caucalis	Apiaceae
Caucalis anthriscus	Cavariella aegopodii;
	Dysaphis crataegi ssp. aethusae
C. incognita = Agrocharis incognita
C. lappula = C. platycarpos
C. latifolia =Turgenia latifolia
C. platycarpos	Aphis [craccivora], fabae; Hyadaphis foeniculi;
	Semiaphis dauci
Caucalis sp.	Aphis spp. (England, BMNH collection; Turkey, BMNH
	collection)

Key to aphids on Caucalis (and Turgenia):-

1	ABD TERG 8 with a supracaudal process. SIPH clavate. ANT PT/BASE 0.7-1.25	…..Cavariella aegopodii
–	No supracaudal process. SIPH tapering. ANT PT/BASE 1.8-5.5	…..2
2	Cauda not longer than its basal width	…..3
–	Cauda much longer than its basal width	…..4
3	SIPH dark. ANT III more than 2 × ANT V	…..Dysaphis crataegi aethusae
–	SIPH pale/dusky. ANT III about 1.1 × ANT V	…..Brachycaudus crassitibiae*
4	SIPH and cauda mainly pale (SIPH often dark-tipped). Head spiculose, with ANT tubercles well developed, their inner faces approximately parallel	…..Aulacorthum solani
–	SIPH dark, cauda pale, dusky or dark. Head not spiculose, ANT tubercles weakly developed	…..5
5	SIPH very small and flangeless, c.0.5 × cauda, with aperture slanted toward midline	…..Semiaphis dauci
–	SIPH at least 0.6 × cauda, with an evident flange	…..6
6	SIPH at least somewhat swollen proximal to apex. ABD TERG 1 and 7 without marginal tubercles (MTu)	…..7
–	SIPH tapering, without any trace of swelling. ABD TERG 1 and 7 with MTu	.….8
7	SIPH clavate, 0.9-1.4 × cauda and 1.6-2.8 × HT II	…..Hyadaphis foeniculi
–	SIPH thick on basal half and slightly swollen proximal to apex (fig. 41b), 0.6-0.8 × cauda and 0.9-1.3 × HT II	…..Hyadaphis coriandri
8	Dorsum without dark pigmentation . Cauda pale or dusky, distinctly paler than SIPH	…..Aphis gossypii
–	Dorsum with at least some dark pigmentation. Cauda and SIPH equally dark	…..9
9	ANT PT/BASE 1.6-2.2. ABD TERG 2-4 without MTu. Dorsal pigmentation when extensive fused between segments to form a shield. ABD TERG 8 with only 2 hairs about equal in length to or shorter than ANT BD III. Longest hairs on hind femur shorter than trochantro-femoral suture	…..Aphis sp. (Turkey, BMNH collection)
–	ANT PT/BASE 2.1-4.1 (if less than 2.4 then ABD TERG 2-4 with MTu). Dorsal pigmentation consisting of segmentally-arranged cross-bands, not fused between segments. ABD TERG 8 with 2-7 hairs much longer than ANT BD III. Longest hairs on hind femur much longer than trochantro-femoral suture	…..10
10	ABD TERG 2-4 regularly with large papillate MTu. R IV+V 0.17-0.18 mm, 1.2-1.5 × HT II. ANT PT 1.7-1.9 × R IV+V	…..Aphis sp. (England, BMNH collection)
	– ABD TERG 2-4 irregularly with small MTu. R IV+V 0.12-0.165 mm, 0.9-1.1 × HT II. ANT PT 2.0-2.8 × R IV+V	…..Aphis fabae

Cayaponia	Cucurbitaceae
Cayaponia sp.	Delfinoia peruviana

Cayratia	Vitaceae
Cayratia ibuensis	Aphis gossypii
C. japonica	Aphis gossypii; Greenidea cayratiae;
	Macrosiphoniella cayratiae

Key to apterae on Cayratia:-

1	SIPH c.0.46-0.50× BL, with numerous long hairs	…..Greenidea cayratiae
–	SIPH much shorter and without hairs	…..2
2	SIPH with a distal zone of polygonal reticulation extending for about half their lengths. ANT tubercles prominent	Macrosiphoniella cayratiae*
–	SIPH without polygonal reticulation. ANT tubercles weakly developed	…..Aphis gossypii

Ceanothus	Rhamnaceae
Ceanothus cordulatus	Illinoia ceanothi
C. cuneatus	Aphis ceanothi
C. hirsutus = C. oliganthus
C. integerrimus	Aphis ceanothi
C. oliganthus	Aphis ceanothi
C. sanguineus	Aphis ceanothi
C. thyrsiflorus	Aphis ceanothi
C. velutinus	Aphis boydstoni, ceanothi; Illinoia ceanothi
Ceanothus spp.	Macrosiphum euphorbiae; Neomyzus circumflexus

Key to aphids on Ceanothus:-

1	ANT tubercles weakly developed. ANT PT/BASE 1.5-2.8. SIPH and cauda dark. ABD TERG 1 and 7 with marginal tubercles	…..2
–	ANT tubercles well developed. ANT PT/BASE longer. SIPH and cauda pale or dusky. ABD TERG 1 and 7 without marginal tubercles	…..3
2	Marginal tubercles small and only present on ABD TERG 1 and 7. Dorsal abdomen with large black presiphuncular sclerites, often linked by a transverse sclerite on ABD TERG 6	……Aphis ceanothi
–	Marginal tubercles broad, nearly flat and present on all of ABD TERG 1-7. Dorsal abdomen pale, without any presiphuncular sclerites	……Aphis boydstoni
3	SIPH very long and thin, 2.2-3.1 × cauda; narrow in middle, with distal part dusky and somewhat swollen, narrowing again before apex, with usually some subapical reticulation	…..Illinoia ceanothi
–	SIPH less than 2.5 × cauda	…..go to key to polyphagous aphids

Cecropia	Cecropiaceae
Cecropia peltata	Aphis aurantii, gossypii, spiraecola
C. hondurensis = C. peltata

(Use key to polyphagous aphids)

Cedrela	Meliaceae
Cedrela odorata	West Indian or Mexican Cedar
	Aphis (Toxoptera) aurantii
C. serrata	[Chromaphis hirsutustibus]
C. sinensis	Aphis odinae

(Use key to polyphagous aphids.)

Cedrus Cedars	Pinaceae
Cedrus atlantica	Cinara cedri, laportei, tellenica; Schizolachnus pineti
C. deodara	Cinara cedri, confinis, curvipes, deodarae,
	laportei, [tenuipes];
	Illinoia morrisoni; [Mindarus abietinus]; [Stomaphis sp.]
C. libani	Cinara cedri, curvipes, laportei
C. libani ssp. brevifolia	Cinara cedri ssp. brevifoliae, laportei

Key to aphids on Cedrus:-

1	ANT PT/BASE more than 1. SIPH long and tubular, swollen distally	…..Illinoia morrisoni
–	ANT PT/BASE less than 1. SIPH are broad hairy cones	…..2
2	R V short, flask-shaped, pointed only at tip, hardly longer than its basal width (fig. 69B). SIPH cones with few hairs, in 1-2 rings around pore	…..Schizolachnus pineti
–	R V acutely pointed, dagger-shaped, usually twice or more as long as its basal width (as in fig. 69A). SIPH cones large and dark with numerous hairs	…..3
3	Antenna 5-segmented. Dorsal hairs of aptera club-shaped, ornamented with numerous barbules (fig. 37A)	…..Cinara laportei
–	Antenna 6-segmented. Dorsal hairs normal, pointed	…..4
4	Hairs on body and appendages short; those on ANT III maximally about as long as basal diameter of segment	…..Cinara curvipes
–	Hairs mostly long; longest hairs on ANT III maximally more than 2 × basal diameter of segment	…..5
5	Dorsal length of HT I shorter than basal width. BL 3.8-7.8 mm	…..Cinara confinis
–	Dorsal length of HT I as long as or longer than basal width (e.g. fig. 37B). BL 2.2-3.6 mm	…..6

6	ABD TERG 1-6 with an extensive pattern of dark sclerotisation	…..Cinara deodarae*
–	ABD TERG 1-6 without any extensive dark sclerotisation	…..7
7	Dorsal length of HT I 0.045-0.060 mm, 1.0-1.12 times longer than basal width. Longest hairs on ABD TERG 7 are 0.090-0.144 mm, and on hind tibia 0.096-0.132 mm	…..Cinara tellenica*
–	Dorsal length of HT I 0.060-0.090 mm, 1.2-1.7 times longer than basal width. Longest hairs on ABD TERG 7 are 0.162-0.240 mm, and on hind tibia 0.156-0.240 mm	…..8
8	Femora and tibiae mainly pale on basal halves. R IV 2.0-2.5 × R V. ANT V 1.2-1.4 × ANT VI	…..Cinara cedri
–	Femora and tibiae mainly dark throughout. R IV 1.8-2.1 × R V. ANT V 1.0-1.2 × ANT VI	…..Cinara cedri ssp. brevifoliae*

Ceiba (including Chorisia)	Malvaceae
Ceiba anfructosa	Aphis gossypii
C. pentandra	Aphis aurantii, gossypii
C. speciosa	Aphis citricidus, gossypii; Macrosiphum euphorbiae;
	Myzus persicae

Use key to polyphagous aphids.

Celastrus	Celastraceae
Celastrus articulatus	Aphis [celastrii], gossypii; Pseudomegoura magnoliae
C. flagellaris	Aphis [celastrii], gossypii, odinae
C. orbiculatus	Aphis [celastrii], fabae, gossypii, odinae, spiraecola;
	Pseudomegoura magnoliae
C. scandens	[Acyrthosiphon pisum];
	Aphis craccivora, fabae, gossypii, spiraecola;
	Aulacorthum solani; Macrosiphum euphorbiae
C. strigillosus	Aphis spiraecola

Use key to polyphagous aphids.

Celmisia	Asteraceae
Celmisia glandulosa	Aulacorthum solani; Brachycaudus helichrysi

Use key to polyphagous aphids.

Celosia	Amaranthaceae
Celosia argentea	Aphis fabae, gossypii; Myzus persicae
(incl. var. cristata)
C. plumosa = C. argentea
C. trigyna	Aphis gossypii
Celosia sp.	Aphis spiraecola

Use key to polyphagous aphids.

Celtis	Ulmaceae
Celtis africana	Aphis aurantii; Shivaphis celti
C. aurantiaca	Aphis gossypii; Shivaphis szelegiewiczi
C. australis	Aphis aurantii, craccivora, spiraecola; Myzus persicae;
	Shivaphis catalpinari, celti, celticola
C. berteroana	Aphis aurantii
C. biondii	Shivaphis catalpinari, celti, szelegiewiczi
C. bungeana	Aphis aurantii, craccivora, spiraecola; Shivaphis celti;
C. caucasica = C. australis
C. cinnamomia	Shivaphis celti
C. eriocarpa = C. australis
C. formosana	Aulacorthum solani
C. hamiltoni	Shivaphis celti
C. iguanaea	Aphis aurantii
C. japonica see sinensis
C. jessoensis	Macromyzella celticola; Prociphilus oriens;
	Shivaphis celti, tilisucta
C. julianae	Shivaphis celti, hangzhouensis
C. koraiensis	[Myzocallis carpini]; Shivaphis catalpinari, celti, tilisucta;
	Stomaphis yanonis
C. kunmingensis	Shivaphis celti
C. laevigata	Shivaphis celti
C. latifolia	Aphis spiraecola
C. nervosa	Shivaphis celti
C. occidentalis	Aphis fabae; [Drepanosiphum platanoidis];
	[Phorodon humuli]; Shivaphis celti; [Tinocallis platani]
C. sinensis (incl. japonica)	Aphis aurantii, [celtis], craccivora, spiraecola;
	[Indomegoura indica]; Paracolopha morrisoni; Pseudomegoura magnoliae;
	Shivaphis catalpinari, celti, hangzhouensis, szelegiewiczi,
	tilisucta;
	Stomaphis yanonis
C. tala	Aphis gossypii
C. tetrandra (incl. var.	Shivaphis celti; Sumatraphis celti
	hamiltoni)
C. triandra	Shivaphis celti
C. willdenowiana = C. sinensis
Celtis sp.	[Sumatraphis tubercaudatus]

Key to species on Celtis:-

(The separation of Shivaphis spp. in couplets 6-10 is largely based on Quednau 2003.)

1	ANT PT/BASE more than 1	…..2
–	ANT PT/BASE less than 1	…..3
2	Head with well-developed, scabrous, apically convergent antennal tubercles. SIPH cylindrical with a well-developed flange and 2-4 subapical rows of polygonal reticulation	….. Macromyzella celticola
–	Without that combination of characters	…..go to key to polyphagous aphids, but note that populations running to Aphis (Toxoptera) aurantii may be A. (T.) celtis (described as having alatae with 3-4 rhinaria on ANT IV)
3	(Alata emerging in spring from galls or leaf-nests.) Media of forewing unbranched	…..4
–	(Apterae and alatae free-living.) Media of forewing of alata once- or twice-branched	…..5
4	(Alata from closed gall.) BL less than 3 mm. Hind wing with one oblique vein. Secondary rhinaria on ANT III-VI, many of them almost completely encircling	…..Paracolopha morrisoni

–	(Alata from leaf-nest.) BL more than 4 mm. Hind wing with 2 oblique veins arising from a common base. Secondary rhinaria on ANT III-V (not VI), narrowly transverse but not extending more than half way around segment	…..Prociphilus oriens
5	BL more than 4mm. Rostrum longer than body	…..Stomaphis yanonis
–	BL less than 3 mm. Rostrum shorter than body	…..6
6	Antenna 4-segmented in aptera, 5-segmented in alata (where known). Posterior abdomen with marginal processes. SIPH tubular, swollen, constricted apically, and with a subapical ring of 4 hairs (fig. 38A)	…..Sumatraphis celti
–	Antenna 6-segmented. Abdomen without marginal processes. SIPH are pores, very small cones, or truncate, without a ring of hairs	…..7
7	Forewing of alata with the membrane between media and Cu1a not bridged by a band of pigment. ANT PT very short, about 3 times as long as wide or less. Apterous viviparae as well as alatae present	…..8
–	Forewing of alata with the membrane between media and Cu1a bridged by a band of pigment. ANT PT short, but at least 6 × longer than its maximum width. All adult viviparae are alate	…..9
8	Apical part of cauda a rounded knob (fig. 38B). ANT III of alata with rhinaria in a line extending over most of length of segment. Fore coxae weakly enlarged, not visible from above at sides of pronotum	…..Shivaphis catalpinari
–	Apical part of cauda finger-like, rather irregular in shape (fig. 38C). Alata with secondary rhinaria concentrated on central part of ANT III. Fore coxae strongly enlarged, visible from above at sides of pronotum	…..Shivaphis celti
9	SIPH as truncate cones about as long as their midlength width (fig. 38D). Membrane between media and Cu1a of forewing bridged by a band of pigment that is broader than long. Dorsal abdomen with a complete series of spinal wax pore plates	…..10
–	SIPH as very short cones, much shorter than wide, or merely as raised pores (figs 38E, F). Membrane between media and Cu1a of forewing with a bridging band of pigment that is not broader than long. Dorsal abdomen with spinal wax pore plates only well developed on ABD TERG 1, 2 and 8	…..11
10	ANT PT/BASE 0.64-0.79. R IV+V 0.155-0.163 mm long, 1.04-1.17 × HT II, and bearing 11-15 accessory hairs. Apices of tibiae spiculose	…..Shivaphis (Sinishivaphis) hanzhouensis
–	ANT PT/BASE 0.41-0.60. R IV+V 0.090-0.098 mm long, about 0.75 × HT II, and bearing 9-10 accessory hairs. Apices of tibiae smooth	…..Shivaphis (Sinishivaphis) tilisucta
11	ANT PT/BASE 0.29-0.40	…..Shivaphis (Sinishivaphis) celticola
–	ANT PT/BASE 0.42-0.50	…..Shivaphis (Sinishivaphis) szelegiewiczi

Cenchrus	Poaceae
Cenchrus bifloris	Aphis gossypii
C. brownii	Sipha flava
C. ciliaris	Hysteroneura setariae; Pseudaphis sijui;
	[Pterasthenia shiraensis]; Rhopalosiphum maidis;
	Sipha flava; Sitobion africanum;
	Tetraneura fusiformis
C. echinatus	Hysteroneura setariae; Rhopalosiphum maidis;
	Tetraneura fusiformis
C. incertus	Rhopalosiphum padi; Sipha flava
C. pauciflorus = C. incertus
C. setigerus	Hysteroneura setariae; Tetraneura fusiformis

Use key to apterae of grass-feeding aphids under Digitaria.

Cenolophium	Apiaceae
Cenolophium denudatum	Aphis fabae, umbelliferarum; Cavariella aegopodii;
	Dysaphis apiifolia (?ssp. petroselini), [koryakini];
	Semiaphis [dauci], horvathi, sphondylii
C. fischeri = C. denudatum

Use key to apterae on Peucedanum.

Centaurea (incl. Cyanus)	Asteraceae
Centaurea adpressa = C. scabiosa ssp. adpressa
C. africana	Aphis gossypii
C. ambigua	Uroleucon jaceae
C. americana	Aphis fabae; Myzus persicae
C. alpestris = C. scabiosa ssp. alpestris
C. apiculata = C. scabiosa ssp. alpestris
C. arenaria	Acaudinum centaureae; Macrosiphoniella staegeri;
	[Protaphis sp.]; Uroleucon jaceae
C. argentea	[Aphis sp. – Leonard 1972a, 99]
C. aristata (incl langeana)	Aphis craccivora; Macrosiphoniella staegeri;
	Paczoskia obtecta; Protaphis terricola;
	Uroleucon jaceae, jaceicola
C. aspera	Paczoskia obtecta; Protaphis hartigi, terricola
C. atropurpurea	Aphis fabae; Uroleucon jaceae
C. balsamita = Stizolophus balsamita
C. behen	Acaudinum beheni; Myzus persicae; Uroleucon jaceae
C. biebersteinii	Macrosiphoniella staegeri; Uroleucon jaceae
C. bracteata	Macrosiphoniella staegeri; Uroleucon jaceae
C. caerulescens = C. hanryi
C. calcitrapa	Aphis fabae; Brachycaudus cardui; Myzus persicae;
	Protaphis centaurea, hartigi, terricola; Uroleucon jaceae
C. carpatica = C. phrygia ssp. carpatica
C. cephalariifolia = C. scabiosa ssp. cephalariifolia
C. cheiranthifolia	Aphis solanella
C. collina	Uroleucon jaceae
C. crocodylium	Aphis fabae; Uroleucon jaceae
C. cyanoides (?)	Brachycaudus helichrysi
C. cyanus (= Cyanus segetum)	Aphis fabae, magnopilosa, solanella, Aphis sp. (Italy,
	BMNH collection);
	Aulacorthum palustre, solani;
	Brachycaudus cardui, helichrysi;
	[Hyalopteroides humilis]; Macrosiphum euphorbiae;
	Myzus ascalonicus, persicae, ornatus; [Nasonovia ribisnigri];
	Paczoskia obtecta; Protaphis terricola;
	Uroleucon compositae, [hypochoeridis], jaceae group,
	[montanivorum], [sonchi];
	[Volutaphis centaureae]
C. dealbata	Brachycaudus cardui; Uroleucon pepperi
C. debeauxii	Uroleucon jaceae
C. depressa	Protrama flavescens, radicis; Uroleucon jaceae, [sonchi]
C. deusta	Macrosiphoniella staegeri; Uroleucon jaceae
C. diffusa	Macrosiphoniella papillata; Protaphis middletonii, terricola;
	Uroleucon jaceae
C. hanryi	Protaphis alexandrae, hartigi; Uroleucon jaceae
C. hyalolepis	Aphis craccivora; Brachycaudus helichrysi
C. hyrcanica	Uroleucon jaceae
C. iberica	Aphis craccivora, fabae, gossypii, magnopilosa, solanella;
	Protrama radicis, [radicis ssp. asiatica];
	Protaphis alexandrae, terricola; [Trama caudata];
	Uroleucon jaceae, jaceae ssp. reticulatum
C. incana = C. pubescens
C. indurata = C. phrygia ssp. indurata
C. jacea (incl. ssp. banatica)	Acaudinum centaureae, longisetosum;
	Aphis fabae, solanella; Brachycaudus cardui;
	Dysaphis centaureae; Paczoskia obtecta; Trama troglodytes;
	Uroleucon jaceae, jaceicola
C. kotschyana	Uroleucon jaceae
C. lanulata	Myzus persicae
C. macrocephala	Myzus ascalonicus, ornatus, persicae
C. macroptilon	Trama troglodytes
C. maculosa	Dysaphis centaureae; Macrosiphoniella staegeri;
	Protaphis terricola group
C. majorovii	Uroleucon jaceicola
C. melitensis	Acaudinum centaureae; Aphis fabae;
	Brachycaudus helichrysi; Protaphis terrcicola;
	Uroleucon jaceae
C. micranthos = C. biebersteinii
C. mollis = Cheirolophus sempervirens
C. monantha = Stemmacantha uniflora
C. montana	Aphis fabae, nasturtii; Uroleucon montanivorum
C. moschata	Aphis fabae, solanella; Brachycaudus cardui;
	Myzus persicae; Uroleucon compositae
C. napifolia	Brachycaudus cardui, helichrysi; Protaphis terricola;
	Uroleucon jaceae
C. nicaeensis = C. sicula
C. nigra	Acaudinum centaureae; Brachycaudus cardui, helichrysi;
	Myzus cymbalariae; Trama troglodytes;
	Uroleucon jaceae group, jaceicola
C. nigrescens	Myzus persicae; Protaphis middletonii; Uroleucon jaceae
C. orientalis	Acaudinum centaureae; Aphis fabae; Myzus persicae;
	Uroleucon jaceae
C. ornata	Uroleucon jaceae
C. oxylepis = C. macroptilon
C. pallescens	Aphis craccivora; Myzus persicae; Uroleucon jaceae
C. paniculata	Acaudinum longisetosum; Brachycaudus helichrysi;
	Macrosiphoniella papillata, staegeri;
	Uroleucon jaceae, jaceicola, jaceicola ssp. pasqualei (?)
C. pannonica	Uroleucon jaceae, jaceae ssp. henrichi
C. pelia	Acaudinum centaureae; Aphis fabae
C. perrottetti	Aphis gossypii
C. phrygia (incl. carpatica,	Dysaphis centaureae;
indurata, melanocalathia,	Uroleucon jaceae, jaceae ssp. henrichi and ssp. reticulatum;
salicifolia, stenolepis)	[Volutaphis centaureae]
C. picris = Rhaponticum repens
C. procurrens	Brachycaudus helichrysi; Paczoskia obtecta;
	Uroleucon jaceae
C. pseudophrygia = C. phrygia ssp. melanocalathia
C. pubescens	Brachycaudus helichrysi
C. pulchella = Hyalea pulchella
C. pullata	Brachycaudus helichrysi
C. rhenana = C. stoebe
C. riaeana	Brachycaudus helichrysi
C. ruthenica	Acaudinum centaureae; Aphis gossypii;
	Macrosiphoniella staegeri; Protaphis alexandrae;
	Uroleucon jaceae
C. scabiosa (incl. adpressa,	Acaudinum centaureae, longisetosum;
alpestris, apiculata,	Aphis fabae, Aphis spp. (BMNH colln, Italy and Sweden);
cephalariifolia, sadleriana,	Dysaphis centaureae; [Macrosiphum rosae];
tenuifolia)	Paczoskia obtecta; Protaphis hartigi, terricola;
	Protrama flavescens, radicis;
	Trama centaureae, troglodytes;
	Uroleucon jaceae, jaceae ssp. henrichi, jaceae ssp.
	reticulatum, jaceicola, [picridis]
C. sempervirens = Cheirolophus sempervirens
C. sergii	Uroleucon jaceae
C. sibirica	Protaphis alexandrae
C. sicula	Brachycaudus cardui, helichrysi; Uroleucon compositae
C. solstitialis	Acaudinum bulgaricum; Brachycaudus cardui;
	Macrosiphoniella papillata; Paczoskia obtecta;
	Protaphis alexandrae, hartigi, terricola;
	Uroleucon jaceae group
C. sphaerocephala (incl.	Acaudinum centaureae; Protaphis terricola;
polyacantha)	Uroleucon jaceae
C. spinabadia = C. hanryi
C. squarrosa = C. virgata ssp. squarrosa
C. stenolepis = C. phrygia ssp. stenolepis
C. stoebe	Acaudinum longisetosum, roumanicum;
	Aphis fabae; Dysaphis centaureae;
	Macrosiphoniella staegeri;
	Protaphis hartigi, terricola, Protaphis sp. (BMNH colln, Czech Republic and Switzerland);
	Protrama radicis; Trama centaureae, troglodytes;
	Uroleucon jaceae, jaceae ssp. henrichi, jaceae ssp.
	reticulatum, jaceicola
C. trichocephala	Uroleucon jaceicola
C. triumfetti (incl. aligera)	Aphis fabae; Paczoskia obtecta; Uroleucon jaceae, jaceicola
C. vallesiaca	Macrosiphoniella staegeri
C. virgata (incl. ssp. squarrosa)	Acyrthosiphon ilka;Aphis magnopilosa
	Macrosiphoniella papillata, staegeri, [Macrosiphoniella
	(Papillomyzus) sp. (Kadyrbekov 2014e)];
	Protaphis alexandrae, [elatior], magnopilosa, terricola,
	Protaphis sp. (Kadyrbekov 2005b);
	Protrama radicis;
	Uroleucon jaceae, jaceae ssp. reticulatum, jaceicola,
	jaceicola ssp. kirgisica
C. vochinensis = C. nigrescens
Centaurea spp.	Abstrusomyzus phloxae;
	[Brachycaudus sp. nr. pruniavium; Bodenheimer &
	Swirski 1957, 338];
	Capitophorus eleaegni; Macrosiphoniella iranica, riedeli;
	Neomyzus circumflexus; Rectinasus buxtoni;
	Smynthurodes betae; [Titanosiphon dracunculi];
	[Trama rara]; [Uroleucon erigeronense]

Key to apterae on Centaurea:-

1	Antennae densely hairy; e.g. base of last antennal segment with more than 20 hairs	…..2
–	Antennae less hairy; base of last antennal segment with less than 10 hairs	..…6
2	HT II greatly elongated, more than 0.5 × hind tibia	……3
–	HT II of normal length	…..5
3	SIPH present as large pores on low pigmented cones. Most apterae alatiform, with dark dorsal markings. ANT PT/BASE 0.4-0.6	…..4
–	SIPH absent. Apterae without dark dorsal markings. ANT PT/BASE 0.14-0.3	…..Trama centaureae or Trama troglodytes
4	HT II 0.72-0.87 × length of hind tibia. Hind tibia 5.0-6.4 × ANT IV. R IV with 8-12 accessory (dorsal) hairs	….. Protrama radicis
–	HT II 0.50-0.70 × length of hind tibia. Hind tibia 6.5-9.2 × ANT IV. R IV with 6-8 accessory (dorsal) hairs	…..Protrama flavescens
5	ANT V BASE and R IV+V both very long, respectively about 1.7 and 2.5 × width of head between antennal bases. ANT II similar in length to ANT I, much shorter than III	.….Rectinasus buxtoni
–	ANT V BASE and R IV+V of normal length , both about 0.5 × width of head between antennal bases. ANT II about twice as long as ANT I, similar in length to III	..…Smynthurodes betae
6	SIPH dark with a distal zone of polygonal reticulation. ANT III with 2-86 rhinaria	…..7
–	SIPH pale or dark, if dark then without any polygonal reticulation. ANT III with 0-10 rhinaria	….17
7	ANT III with only 2-8 rhinaria on basal half. SIPH 0.9-1.3 × cauda. Crescent-shaped antesiphuncular sclerites present	…..Macrosiphoniella staegeri
–	ANT III with 8-86 rhinaria. SIPH 1.05-2.8 × cauda. Antesiphuncular sclerites present or absent	…..8
8	Dorsal abdominal hairs all arising from pale tubercles	…..9
–	Dorsal abdominal hairs all or mostly arising from dark scleroites	…..11
9	Hind tibiae with extensive pale middle regions. Hind femora dappled pale and dark, with a pale distal spot	…..Macrosiphoniella iranica
–	Hind tibiae wholly black. Hind femora black over distal 0.5 or more of length	…..10
10	Femora pale over basal 0.3-0.5 of length	…..Macrosiphoniella riedeli
–	Femora pale over only basal 0.1-0.2 of length	…..Macrosiphoniella papillata
11	Bases of SIPH almost ringed by large semicircular presiphuncular, and less extensive postsiphuncular, sclerites	…..Paczoskia obtecta
–	Presiphuncular sclerites absent or fragmented	…..12
12	Coxae and cauda pale. SIPH 1.2-1.6 × cauda, which bears 23-39 hairs	…..Uroleucon pepperi
–	Coxae dark. Cauda pale or dark, but if pale then cauda bears 7-18 hairs	…..13
13	ANT I bearing 10-15 hairs. SIPH pale in summer and dark in early spring, 2.0-3.0 × the pale cauda which bears 8-18 hairs	…..Uroleucon jaceicola (s. str.)
–	ANT I bearing 6-8 hairs. SIPH 1.4-2.6 × cauda which is pale or dark, but if pale bears 7-11 hairs	…..14
14	SIPH 1.8-2.6 × the pale cauda which bears 7-11 hairs	…..Uroleucon mongolicum
–	SIPH 1.4-2.2 × the dark cauda which bears 12-30 hairs	…..15
15	Tibiae wholly dark. Hind femora with basal half pale and distal half dark, with a rather sharp transition between. ANT III with 16-54 rhinaria often confined to basal half (but up to 81 rhinaria extending over 0.85 of ANT III in alatiform specimens with rudimentary ocelli occurring when alatae are being produced in early summer). SIPH 1.4-1.8 × cauda	…..Uroleucon jaceae
–	Tibiae with paler middle section. Hind femora pale over either much less or clearly more than half of length. ANT III with 28-86 rhinaria often extending over more than half of length. SIPH 1.7-2.2 × cauda	…..16
16	R IV+V 1.1-1.4 × HT II. Femora mainly dark, only pale on basal 0.2-0.3 of length	…..Uroleucon compositae
–	R IV+V 1.6-2.0 × HT II. Femora pale over basal 0.67-0.75 of length	…..Uroleucon montanivorum
17	Cauda very broadly rounded, crescent-shaped, with length much less than half of its basal width	…..18
–	Cauda helmet-shaped, triangular, tongue- or finger-shaped, with length more than half of its basal width	…..22
18	SIPH 2.3-4.0 × HT II, with minimum width not greater than width of hind tibia at midlength. Subgenital plate with 10-24 hairs on its anterior half	…..19
–	SIPH usually 1.6-2.5 × HT II, with minimum width clearly greater than width of hind tibia at midlength. Subgenital plate with 2-4 hairs on anterior half	…..21
19	Femoral and trochantral hairs, and those on anterior abdominal sternites, short and blunt, maximally 0.4 × trochantro-femoral suture	…..Acaudinum centaureae
–	Femoral, trochantral and ventral body hairs long, with finely pointed apices; not much shorter than trochantro-femoral suture	…..20
20	HT II 0.136-0.177 mm, and SIPH 0.49-0.75 mm, the product of the two lengths (HT II × SIPH) being 0.080-0.115	…..Acaudinum longisetosum
–	HT II 0.125-0.150 mm, and SIPH 0.34-0.53 mm, HT II × SIPH being 0.042-0.077	…..Acaudinum roumanicum
21	Femoral and trochantral hairs long and finely-pointed, maximally 0.7-1.05 × trochantro-femoral suture. SIPH 0.50-0.58 × ANT PT. (Al. without secondary rhinaria on ANT IV)	…..Acaudinum beheni
–	Femoral and trochantral hairs short, mostly blunt, maximally 0.4 × trochantro-femoral suture. SIPH 0.39-0.49 × ANT PT. (Al. with 2-6 secondary rhinaria on ANT IV)	…..Acaudinum bulgaricum
22	Cauda helmet-shaped or triangular, 0.7-1.35 × its basal width	…..23
–	Cauda tongue- or finger-shaped, more than 1.4 × its basal width	…..28
23	ABD TERG 1 and 7 always with marginal tubercles (MTu), larger than any MTu that may be present on other abdominal segments. Spinal tubercles (STu) absent. Cauda bluntly triangular, without any basal constriction	…..24
–	ABD TERG 1 and 7 either without MTu, or MTu are present in association with similar large flat MTu on most other abdominal segments, and commonly also with STu on head and ABD TERG 7-8. Cauda helmet-shaped or pentagonal, often somewhat constricted at base	…..26
24	SIPH as short cones, clearly shorter than their basal widths and clearly shorter than (about 0.6 ×) cauda. MTu on ABD TERG 1 and 7 thin and tapering	…..Xerobion zoijae*
–	SIPH as short tubes, cylindrical or slightly tapering, about as long as or longer than their basal widths and at least 0.7 × cauda. MTu on ABD TERG 1 and 7 quite large and broad-based	…..25
25	ANT PT/BASE 0.7-1.2. Dorsal abdominal pigmentation variable but never with dark cross-bands on all tergites	…..Protaphis terricola group (incl. alexandrae, centaurea, hartigi, hyaleae and an undescribed species on Centaurea rhenana in C Europe)
–	ANT PT/BASE 1.7-2.3. Dorsal abdominal pigmentation variable but often comprising complete or fragmented dark cross-bands on all tergites	…..Protaphis middletonii group
26	Large, flat MTu present on most segments, their diameters very much greater than that of spiracular apertures, which are broadly reniform and contiguous on ABD TERG 1 and 2. STu often present on head and ABD TERG 7-8	…..Dysaphis centaureae
–	MTu and STu only intermittently or rarely present and much smaller than spiracular apertures, which are large and rounded and not contiguous on ABD TERG 1 and 2	…..27
27	Dorsum with an extensive black shield. SIPH dark, imbricated, 1.7-3.4 × cauda. ANT III 0.31-0.47 mm, 2.4-3.4 × HT II	…..Brachycaudus cardui
–	Dorsum without dark markings. SIPH pale, smooth-surfaced, 0.8-1.5 × cauda. ANT III 0.07-0.25 mm, 0.9-2.2 × HT II	…..Brachycaudus helichrysi
28	Well-developed rounded marginal tubercles (MTu) present on ABD TERG 2-5, as well as very large ones on 1 and 7. R IV+V about equal in length to ANT III	…..Aphis sp. (Italy, BMNH collection)
–	Papilliform MTu absent or sporadically present on ABD TERG 2-4; only ever consistently present on ABD TERG 1 and 7. R IV+V much shorter than ANT III	…..29
29	SIPH 1.9-2.2 × the similarly dark cauda. Papilliform MTu usually present on at least some of ABD TERG 2-4	…..Aphis sp. (Sweden, BMNH collection)
–	SIPH 0.7-2.5 × cauda, but if more than 1.8 × then either SIPH and cauda are both pale or cauda is distinctly paler than dark SIPH, and MTu are rarely present on ABD TERG 2-4	…..30
30	Cauda black with 6-8 hairs, and dorsum pale with only a dusky band on ABD TERG 8. R IV+V 1.2-1.3 × HT II. ANT PT/BASE 1.5-1.95	…..Aphis sp. (Italy, BMNH collection)
–	Cauda pale or dark; if black and with only 6-8 hairs then dorsum has extensive black sclerotisation, R IV+V is 0.8-1.0 × HT II and ANT PT/BASE 1.9-3.6	…..31
31	ANT tubercles well-developed with smooth, divergent inner faces. SIPH without subapical polygonal reticulation	…..32
–	Without that combination of characters. If ANT tubercles are well-developed then either they are steep-sided and somewhat spiculose or scabrous, or SIPH have subapical polygonal reticulation	…..33
32	Dorsal hairs thick and capitate, as long as ANT BD III or longer	…..Capitophorus elaeagni
–	Dorsal hairs small and inconspicuous	….. Acyrthosiphon ilka
33	ANT tubercles well-developed, their inner faces steep-sided and slightly scabrous or spiculose. Head capsule without spicules dorsally, but slightly spiculose ventrally. ANT III with 1-3 small rhinaria near base. SIPH without polygonal reticulation	…..Aulacorthum palustre
–	Without that combination of characters. If ANT tubercles are well-developed, then either head is markedly spinulose at least ventrally, with inner faces of ANT tubercles markedly scabrous and parallel or apically convergent, or SIPH have several rows of subapical polygonal reticulation. ANT III with 0-10 rhinaria	…..go to key to polyphagous aphids
	(specimens running to Aphis fabae could be A. magnopilosa Nevsky)

Centaurium (including Erythraea)	Gentianaceae
Centaurium erythraea	Aphis gentianae; Myzus cerasi, erythraeae;
	Sciamyzus cymbalariae
C. littorale	Myzus cerasi
C. pulchellum	Aphis gentianae
C. tenuiflorum	Brachyunguis harmalae
C. umbellatum = C. erythraea
C. vulgare = C. littorale

Key to apterae on Centaurium:-

1.	ANT PT/BASE 0.4-0.7. SIPH 0.3-0.6 × cauda	…..Brachyunguis harmalae
–	ANT PT/BASE more than 1. SIPH as long as or longer than cauda	…..2
2	Head smooth, ANT tubercles weakly developed, front of head straight or sinuous in dorsal view. Large, domed marginal tubercles (MTu) present on ABD TERG 1-5 and 7	…..Aphis gentianae
–	Head scabrous/spinulose, ANT tubercles well-developed, scabrous, their inner faces convergent. Small MTu irregularly present on ABD TERG 1-4, never on 7	…..3
3.	SIPH black, tapering/cylindrical, more than 0.2 × BL and longer than ANT III	…..Myzus erythraeae (= cerasi?)
–	SIPH pale/dusky, slightly swollen on distal half, less than 0.2 × BL and shorter than ANT III	…..Myzus cymbalariae

Centotheca	Poaceae
Centotheca lappacea	Pentalonia gavarri (as nigronervosa?)
C. latifolia = C. lappacea
C. mucronata	Pseudoregma panicola

Use key to apterae of grass-feeding aphids under Digitaria.

Centranthus	Valerianaceae
C. angustifolius	Aphis fabae, spiraephaga; Macrosiphum euphorbiae, rosae
C. calcitrapa	Aphis fabae, solanella; Macrosiphum rosae, euphorbiae;
	Myzus ornatus
C. coccineus see C. ruber
C. macrosiphon	Aphis craccivora; Macrosiphum rosae; Myzus persicae
C. ruber (incl. var. coccineus)	Aphis fabae, gossypii, solanella, spiraecola, spiraephaga;
	Macrosiphum centranthi, euphorbiae, rosae;
	Myzus ascalonicus, ornatus, persicae

Key to apterae on Centranthus:-

1	SIPH with a subapical zone of polygonal reticulation	…..2
–	SIPH without polygonal reticulation	…..4
2	Head and ANT I-II dark. SIPH wholly dark	…..Macrosiphum rosae
–	Head and ANT I-II pale. SIPH pale at least at their bases	…..3
3	Apices of femora and SIPH dark. ANT 1.3-1.7 × BL. Longest hairs on ABD TERG 3 are 33-50 mm long. Cauda with 11-19 hairs	…..Macrosiphum centranthi
–	Apices of femora and SIPH pale/dusky. ANT 0.9-1.4 × BL. Longest hairs on ABD TERG 3 are 20-37 mm long. Cauda with 8-12 hairs	…..Macrosiphum euphorbiae
4	Head spiculose, with well-developed, steep-sided or apically convergent ANT tubercles. ABD TERG 1 and 7 without marginal tubercles (MTu)	…..go to key to polyphagous aphids, starting at couplet 5
–	Head not spiculose, ANT tubercles weakly developed. ABD TERG 1 and 7 with MTu	…..5
5	Abdomen without any dark markings on ABD TERG 1-6, and without or with only a small lightly-pigmented sclerites on ABD TERG 8, or 7 and 8	…..6
–	Abdomen with either a dark dorsal shield or at least some scattered dark markings on ABD TERG 1-6, following the polygonal pattern of reticulation of the cuticle, and usually with dark transverse sclerites on ABD TERG 7 and 8	…..7
6	Cauda paler than SIPH, and bearing 4-7(-8) hairs. Longest hind femoral hairs only 0.4-0.7 × diameter of trochantro-femoral suture	…..Aphis gossypii
–	Cauda as dark as SIPH, usually with a midway constriction, and bearing 7-15 hairs. Longest hind femoral hairs more than 0.8 × diameter of trochantro-femoral suture	…..Aphis spiraecola
7	Dorsal abdomen with an extensive solid black sclerite centred on ABD TERG 4-5. Cauda rather pointed and bearing 4-7 hairs	…..Aphis craccivora
–	Dorsal abdomen often with variably developed dark markings, but without an extensive black sclerite. Cauda rounded apically and bearing 7-27 hairs	…..8
8	Longest hairs on ANT III 0.5-0.9 × BD III. R IV+V 0.65-0.92 × HT II. SIPH 0.7-1.1 × cauda. Femora pigmented throughout length	…..Aphis spiraephaga
–	Longest hairs on ANT III 0.8-3.4 × BD III. R IV+V 0.9-1.4 × HT II. SIPH 0.8-1.9 × cauda. Femora with unpigmented section at base	…..Aphis fabae or A. solanella
	(for separation of these two species see couplet 35 of polyphagous aphids key)

Centrosema	Fabaceae
Centrosema arenarium	Aphis gossypii; Microparsus brasiliensis
C. pubescens	Aphis craccivora

Key for apterae on Centrosema:-

1	ANT tubercles well-developed. SIPH with basal half pale, distal half dark and slightly clavate. (Alatae with black-bordered wing veins)	…..Microparsus brasiliensis
–	ANT tubercles weakly developed. SIPH tapering, wholly dark	…..2
2	Dorsal abdomen with an extensive dark sclerite. Cauda dark	…..Aphis craccivora
–	Dorsal abdomen without dark markings. Cauda paler than SIPH	…..Aphis gossypii

Cephalanthera	Orchidaceae
Cephalanthera damasonium	Aphis fabae, solanella
C. longifolia	Aulacorthum solani
C. rubra	Aphis fabae
Cephalanthera sp.	Aphis craccivora

Use key to polyphagous aphids, or try key to orchid-feeding aphids under Cymbidium.

Cephalanthus	Rubiaceae
Cephalanthus occidentalis	Aphis cephalanthi

Cephalaria	Dipsacaceae
C. corniculata = C. uralensis
C. gigantea	Aphis cephalariae; Dysaphis cephalarioides;
	Macrosiphum rosae
C. joppensis	Brachycaudus helichrysi
C. joppica = C. joppensis
C. leucantha	Dysaphis cephalarioides
C. syriaca	Aphis gossypii; Myzus persicae
C. tatarica = C. gigantea
C. uralensis	Dysaphis cephalarioides; Macrosiphum rosae

Key to apterae on Cephalaria:-

1	Head black with well-developed ANT tubercles, their inner faces smooth and divergent. SIPH long and black, 0.3-0.45 × BL, with a subapical zone of polygonal reticulation	…..Macrosiphum rosae
–	Without that combination of characters. If ANT tubercles are well developed then head and SIPH are not black	…..2
2	Large flat marginal tubercles (MTu) present on thorax and ABD TERG 1-5 and 7 (and some-times on 6), and similar spinal tubercles (STu) on head, pronotum, ABD TERG 1, 7 and 8. Dorsal abdomen with dark sclerites	…..Dysaphis cephalarioides
–	MTu and STu if present then small and tubercular and restricted to fewer segments. Dorsal abdomen with or without dark sclerites	…..3
3	Dorsum with extensive dark sclerotisation varying from an almost solid carapace to broad cross-bands (the latter in small midsummer specimens). Longest hairs on ANT III 1.8-2.8 × BD III. ABD TERG 8 with 6-12 hairs and cauda with 12-20 hairs	…..Aphis cephalariae
–	Without that combination of characters	…..go to key to polyphagous aphids

Cephalonoplos see Cirsium

Asteraceae

Cephalotaxus	Cephalotaxaceae
Cephalotaxus drupacea	[Cinara longipennis]; Mindarus japonicus

Cerastium	Caryophyllaceae
C. alpinum	Myzus certus, icelandicus, persicae, polaris
C. angustifolium = C. arvense
C. arvense	Aphis cerastii, sambuci; Aulacorthum solani;
	Brachycolus cerastii;
	Myzus ascalonicus, certus, cymbalariae; [Sitobion avenae];
	Smynthurodes betae
C. biebersteinii	Myzus cymbalariae
C. caespitosum = C. fontanum ssp. vulgare
C. cerastoides	Acyrthosiphon ilka; Aphidura alatavica;
	Macrosiphum stellariae
C. davuricum	Brachycolus cerastii, cucubali; Macrosiphum euphorbiae
C. diffusum	Myzus certus
C. edmonstonii = C. nigrescens
C. fontanum (incl.	Aphidura alatavica; Aulacorthum solani;
holosteoides, triviale, vulgare)	Brachycaudus helichrysi; Brachycolus cerastii;
	Macrosiphum euphorbiae;
	Myzus ascalonicus, certus, cymbalariae, persicae, polaris
C. glomeratum	Abstrusomyzus phloxae; Aphis fabae; Aulacorthum solani;
	Brachycaudus helichrysi; Brachycolus cerastii;
	Macrosiphum euphorbiae; Myzus ascalonicus, persicae
C. holosteoides = C. fontanum ssp. vulgare
C. ligusticum	Myzus certus
C. macranthum	Myzus cymbalariae
C. nigrescens	Acyrthosiphon auctum
C. pumilum	Myzus ascalonicus, certus, persicae
C. semidecandrum	Aulacorthum solani; Myzus ascalonicus, certus, persicae
C. soleirolii	Aphidura corsicensis
C. sylvaticum	Aulacorthum solani
C. tetrandrum = C. diffusum
C. tianschanicum	Acyrthosiphon ilka; Aulacorthum solani;
	Brachycolus cerastii, cucubali
C. tomentosum	Aulacorthum solani; Brachycolus cerastii;
	Myzus ascalonicus, certus, cymbalariae
C. triviale = C. fontanum ssp. vulgare
C. uniflorum	Thecabius cerastii
C. vulgatum =C. glomeratum
Cerastium spp.	[Nasonovia brevipes]

Key to apterae on Cerastium:-

1	ANT PT/BASE less than 0.5. SIPH absent	…..2
–	ANT PT/BASE more than 1.5. SIPH present, tubular (sometimes small)	…..3
2	Primary rhinaria ringed with short hairs. Dorsal abdomen with wax pore plates	…..Thecabius cerastii
–	Primary rhinaria with sclerotic, hairless rims. Dorsal abdomen without wax pore plates	…..Smynthurodes betae
3	Head smooth or wrinkled, or with a few spicules on ventral side only	…..4
–	Head densely spiculose or nodulose	…..16
4	SIPH very small, less than 0.6 × cauda, conical or barrel-shaped, with flange reduced or absent	…..5
–	SIPH more than 0.7 × cauda	…..7
5	SIPH much longer than their basal width, elongate barrel-shaped, about 0.5 × cauda, with a small flange and normal-sized aperture	…..Brachycolus cucubali
–	SIPH shorter than or about as long as their basal width, less than 0.33 × cauda, flangeless and with a reduced aperture	…..6
6	ABD TERG 8 with a small rounded median process bearing two hairs. R IV+V at least 0.9 × HT II, and longer than ANT IV	…..Brachycolus cerastii
–	ABD TERG 8 without a median process. R IV+V 0.55-0.72 × HT II, shorter than ANT IV	…..Brachycolus stellariae
7	ABD TERG 1 and 7 (at least) with marginal tubercles (MTu)	…..8
–	ABD TERG 1 and 7 without MTu	…..10
8	MTU absent from ABD TERG 2-4, or only intermittently present and small on these segments	…..Aphis fabae
–	Large MTu present on ABD TERG 2-4 as well as 1 and 7	…..9
9	SIPH uniformly dark, 2.1-3.5 × cauda. ANT PT/BASE 2.1-2.9	…..Aphis sambuci
–	SIPH paler at bases, less than 2 × cauda (?). ANT PT/BASE 3.2-3.6	…..Aphis cerastii*
10	Cauda short, helmet-shaped, not longer than its basal width. SIPH with a subapical annular incision. Spiracular apertures large and rounded	…..Brachycaudus helichrysi
–	Cauda tongue-shaped, longer than its basal width. Spiracular apertures reniform	…..11
11	SIPH with polygonal reticulation on subapical 0.12-0.20 of length	…..12
–	SIPH without any distinct zone of polygonal reticulation	…..13
12	Femora usually with a dark spot or patch near apices (Fig.51a). ABD TERG 2-3 with longest hair 26-56 μm, usually as long as or longer than ANT BD III. Subgenital plate with 2-13 hairs in addition to those on posterior margin	…..Macrosiphum stellariae
–	Femora pale or only slightly dusky at apices. ABD TERG 2-3 with longest hair 21-37 μm, usually shorter than ANT BD III. Subgenital plate with 2(-4) hairs on anterior part	…..Macrosiphum euphorbiae

13	Dorsal abdomen with dark sclerotisation, either as separate sclerites at base of dorsal hairs or as more extensive bars or broken patches. ANT shorter than BL, and ANT III without rhinaria. SIPH dusky/dark, especially towards apices, and slightly or distinctly swollen on distal half	…..14
–	Dorsal abdomen without dark sclerotisation. ANT longer than BL. ANT III usually with 1-3 rhinaria near base. SIPH pale, tapering/cylindrical	…..15
14	SIPH with very slight distal swelling, and 1.8-2.0 × cauda. Dorsal abdomen with separate rounded dark sclerites at bases of dorsal hairs	…..Aphidura corsicensis
–	SIPH distinctly swollen on distal half, and 1.5-1.7 × cauda. Dorsal abdomen with variable but more extensive sclerotisation, consisting of a broken spino-pleural patch or cross-bands	…..Aphidura alatavica

15	SIPH 0.25-0.33 × BL, and 1.5-2.4 × cauda	…..Acyrthosiphon ilka
–	SIPH 0.11-0.17 × BL, and 0.85-1.33 × cauda	….. Acyrthosiphon auctum
16	SIPH tapering gradually from base to flange. ANT III usually with 1-2 small rhinaria near base	…..Aulacorthum solani
–	SIPH slightly to moderately swollen distally. ANT III without rhinaria	…..17
17	SIPH 0.54-0.81 × ANT III	…..18
–	SIPH 0.82-1.34 × ANT III	…..19
18	Inner faces of ANT tubercles approximately parallel in dorsal view. SIPH almost smooth or weakly imbricated, with narrowest part of basal “stem” not wider than hind tibia at midlength. Dorsal cuticle smooth or slightly wrinkled	…..Myzus ascalonicus
–	Inner faces of ANT tubercles with convergent apices. SIPH heavily imbricated or scabrous, with narrowest part of stem a little wider than hind tibia at midlength. Dorsal cuticle scaly	…..Myzus cymbalariae
19	ANT tubercles not apically convergent. SIPH rather short and thick, dark, with width of narrowest part of stem more than 0.13 of length. ANT 5- or 6-segmented, with ANT PT/BASE 1.1-2.8	…..Myzus polaris
–	ANT tubercles apically convergent, or with apically convergent processes. SIPH pale or dusky with narrowest part of stem less than 0.13 of length. ANT always 6-segmented, with ANT PT/BASE 2.6-5.1	…..20
20	ANT tubercles themselves rather low, but with scabrous processes extending forward from ANT bases. SIPH weakly swollen subapically (over about distal 0.25). Dorsum with an evident reticulate pattern	…..Abstrusomyzus phloxae
–	ANT tubercles broadly rounded, without forwardly-directed processes. SIPH slightly to moderately swollen over about distal 0.5. Dorsum without a reticulate pattern	…..21
21	R IV+V in most specimens with only one pair of lateral accessory hairs (plus 0-3 ventral accessory hairs). Value of function CAUDA/(ANT III × PT) in range 0.80-1.52, but rarely more than 1.25 except in small specimens (those with ANT III less than 0.32 mm)	…..Myzus persicae
–	R IV+V in most specimens with two pairs of lateral accessory hairs. Value of function CAUDA/(ANT III × PT) in range 1.2-2.7 (rarely less than 1.25)	…..22
22	R IV+V shorter than or about as long as (0.85-1.1 × ) ANT BASE VI	…..Myzus certus
–	R IV+V usually longer than (1.0-1.2 × ) ANT BASE VI	…..Myzus icelandicus

Cerasus see Prunus

Rosaceae

Ceratocarpus	Amaranthaceae
Ceratocarpus arenarius	Aphis craccivora

Ceratocephalus	Ranunculaceae
Ceratocephalus falcatus	Dysaphis pulverina

Ceratochloa see Bromus

Poaceae

Ceratoides	Amaranthaceae
Ceratoides ewersmanniana = Krascheninnikovia ewersmanniana
C. latens = Krascheninnikovia ceratoides
C. papposa = Krascheninnikovia ceratoides

Ceratonia	Fabaceae
Ceratonia. siliqua	Carob
	Aphis craccivora, gossypii
	Use key to polyphagous aphids.

Ceratophyllum	Ceratophyllaceae
Ceratophyllum submersus	Sipha glyceriae
Ceratophyllum sp.	Rhopalosiphum nymphaeae

Use key to apterae on Sagittaria.

Ceratostigma	Plumbaginaceae
Ceratostigma willmottianum	Myzus ornatus, persicae

Ceratotheca	Pedaliaceae
Ceratotheca sesamoides	Aphis gossypii

Cercidiphyllum	Cercidiphyllaceae
Cercidiphyllum japonicum	[Aphis sp. (Leonard 1972, 99)]
	Aulacorthum cercidiphylli; Myzus persicae
C. magnificum	Aulacorthum cercidiphylli

Key to aphids on Cercidiphyllum:-

–	Inner faces of antennal tubercles parallel or slightly divergent in dorsal view. ANT III of aptera usually with 1-3 small rhinaria near base. Femora usually dark apically. Alata without a black dorsal abdominal patch	…..Aulacorthum cercidiphylli
–	Inner faces of antennal tubercles convergent in dorsal view. ANT III of aptera never with rhinaria. Alata with a black dorsal abdominal patch	…..Myzus persicae

Cercis	Fabaceae
Cercis canadensis	Longistigma caryae; Aphis pawneepae
C. chilensis	Aulacorthum solani
C. siliquastrum	Judas Tree
	Aphis craccivora, fabae, spiraecola; Myzus persicae

Key to apterae on Cercis:-

1	BL more than 4 mm. ANT PT/BASE less than 1. Alata with pterostigma extending around tip of forewing	…..Longistigma caryae
–	BL less than 3 mm. ANT PT/BASE more than 1.5. Alata with pterostigma stopping short of forewing tip	…..2
2	SIPH short and dark, similar in length to the dark triangular cauda which bears c.20 hairs. ANT PT/BASE slightly less than 2. Prothorax with a pair of very large marginal tubercles. Alata with 2-5 (commonly only 2) secondary rhinaria on basal part of ANT III	…..Aphis pawneepae
–	Without that combination of characters	…..go to key to polyphagous aphids

Cercocarpus	Rosaceae
Cercocarpus montanus	[Acyrthosiphon sp. nr pseudodirhodum; Aphis cercocarpi;
	Illinoia gracilicornis]
C. parvifolius = C. montanus

Records of aphids collected/and or described from Cercocarpus in western USA are now thought to be based on a misidentification of another rosaceous shrub genus, Holodiscus (Jensen 2021).

Cereus	Cactaceae
Cereus nycticaulus = Selenicereus grandiflorus
C. triangularis	Aphis (Toxoptera) aurantii
Cereus sp.	Aphis gossypii

Use key to polyphagous aphids.

Cerinthe	Boraginaceae
Cerinthe glabra	Brachycaudus cerinthis; Macrosiphum cerinthiacum
C. major	Brachycaudus bicolor; Macrosiphum cerinthiacum
C. minor	Aphis fabae; Brachycaudus bicolor, cerinthis;
	Macrosiphum cerinthiacum, euphorbiae, [stellariae]

Key to apterae on Cerinthe:-

1	Cauda semi-circular or helmet-shaped, shorter than its basal width. Spiracular apertures large and rounded. Dorsum with broad dark transverse bands, separate or partially fused between tergites. ANT tubercles undeveloped. ANT III without rhinaria. SIPH dark, without polygonal reticulation	…..2
–	Without that combination of characters	…..3
2.	Large, flat marginal tubercles (MTu), usually larger than spiracles, present on all thoracic segments and ABD TERG 1-7. SIPH about 2 × cauda, with a large flange	…..Brachycaudus bicolor
–	MTu only irregularly present and always smaller than spiracles. SIPH very short, conical, similar in length to or shorter than cauda, with an undeveloped or small flange	…..Brachycaudus cerinthis
3	ANT tubercles well developed, smooth, with inner faces divergent. ANT III with 1-20 rhinaria. SIPH long, mostly pale, with a darker or duskier subapical zone of polygonal reticulation; about 2 × the long finger-like cauda	…..4
–	Without that combination of characters	…..go to key to polyphagous aphids
4	Legs with dark spots near femoral apices. ANT III with 8-20 rhinaria	…..Macrosiphum cerinthiacum
–	Femora pale or only slightly dusky at apices. ANT III with 1-10 rhinaria	…..Macrosiphum euphorbiae

Cerinthodes	Boraginaceae
Cerinthodes paniculatum see Mertensia paniculata

Ceropegia	Apocynaceae
Ceropegia linearis ssp. woodii = C. woodii
C. radicans	Aphis nerii
C. stapeliiformis	Aphis nerii
C. woodii	Neomyzus circumflexus

Use key to polyphagous aphids.

Ceropteris	Polypodiaceae
Ceropteris calomelanos	Idiopterus nephrelepidis

(or try key to fern-feeding aphids under Polypodium)

Cestrum	Solanaceae
Cestrum aurantiacum	Aphis fabae, spiraecola; Aulacorthum solani;
	Myzus persicae
C. diurnum	Aphis aurantii, fabae, gossypii, spiraecola;
	Aulacorthum solani; Myzus persicae
C. elegans	Aphis fabae, spiraecola; Myzus persicae
C. euanthes	Aphis solanella; Myzus persicae
C. fasciculatum	Aphis aurantii, fabae, gossypii, spiraecola;
	Aulacorthum solani; Brachycaudus helichrysi;
	[Greenideoida lutea]; Myzus ornatus, persicae;
	Neomyzus circumflexus
C. laevigatum	Aphis spiraecola
C. laurifolium	Aphis spiraecola
C. leucocarpum = C. nocturnum
C. newellii = C. fasciculatum
C. nocturnum	Aphis aurantii, craccivora, fabae, gossypii, solanella,
	spiraecola;
	Aulacorthum solani; [Eriosoma lanigerum];
	Myzus persicae
C. parqui	Aphis aurantii, fabae, solanella, spiraecola;
	Myzus persicae
C. pseudoquina = C. euanthes
C. purpureum = C. elegans
Cestrum spp.	Aphis nasturtii, Aphis sp.(India, BMNH collection);
	Pseudomegoura magnoliae; [Sitobion rosaeformis]

Key to apterae on Cestrum:-

–	SIPH and cauda both black, SIPH 0.8-0.9 × cauda which bears 6-8 hairs. ANT PT/BASE 1.6-1.95. R IV+V 1.1-1.3 × HT II	….. Aphis sp.(India, BMNH collection)
–	Without that combination of characters	…..go to key to polyphagous aphids

Ceterach see Asplenium	Aspleniaceae
Ceterach officinarum see Asplenium ceterach

Chaenactis	Asteraceae
Chaenactis douglasii	Uroleucon (Lambersius) sp. (western USA, BMNH
	collection)

Chaenomeles	Rosaceae
Chaenomeles japonica	Aphis craccivora, fabae, frangulae, gossypii, nerii, pomi,
(incl. maulei)	spiraecola, spiraephaga;
	Aulacorthum solani;
	Brachycaudus helichrysi, [persicae];
	Illinoia macgillivrayae; Macrosiphum euphorbiae;
	Myzus ornatus, persicae; Ovatus insitus, malisuctus;
	Rhopalosiphum oxyacanthae, [nymphaeae, padi]
Ch. lagenaria	Aphis gossypii, nerii, pomi, spiraecola;
	Brachycaudus helichrysi;
	Dysaphis sp. (Japan; Stroyan 1985 and BMNH collection);
	Macrosiphum euphorbiae; Myzus persicae;
	[Sitobion sp. (Millar 1994)]
Ch. maulei = Ch. japonica
Ch. sinensis	Aphis spiraecola; Myzus persicae;
	Ovatus insitus, Ovatus sp. near crataegarius (?malicolens;
	Korea, BMNH collection and Japan, Moritsu 1983);
	Prociphilus chaenomelis; Pseudomegoura magnoliae; [Sappaphis piri]
Ch. speciosa	Aphis citricidus, gossypii, pomi; Aulacorthum solani;
	Myzus ornatus, persicae; Ovatus malisuctus;
	Schizaphis chaenometicola; [Sitobion sp. (Millar 1994)]
Ch. trichogyna = Ch. japonica

Key to apterae on Chaenomeles (except first couplet, also applicable to alatae):-

1	ANT PT/BASE less than 0.3. SIPH absent or as very small pores. Wax gland plates on head, thorax and abdomen	…..Prociphilus chaenomelis
–	ANT PT/BASE more than 1.5. SIPH present, tubular. No wax gland plates	…..2
2	Head with well-developed ANT tubercles, their inner faces scabrous or at least somewhat spiculose, and steep-sided or apically convergent	…..3
–	Head with ANT tubercles either absent or weakly developed, or very well developed and smooth and divergent	…..8
3	Genital plate enlarged and produced posteriorly. SIPH dark, very coarsely imbricated	…..Ovatus malisuctus
–	Genital plate normal. SIPH pale, weakly to moderately imbricated	…..4
4	ANT III usually with 1-2 small rhinaria near base. Inner faces of antennal tubercles spiculose, approximately parallel	…..5
–	ANT III without rhinaria. Inner faces of ANT tubercles scabrous, convergent apically	…..6
5	Dorsal side of head almost devoid of spicules. SIPH slightly clavate. Femora dark except at bases	…..Pseudomegoura magnoliae
–	Head densely spiculose dorsally as well as ventrally. SIPH tapering/ cylindrical with no trace of swelling. Femora dark only at apices	…..Aulacorthum solani
6	SIPH slightly clavate. R IV+V 1.0-1.2 × HT II. ANT PT/BASE 3.1-4.6	…..Myzus persicae
–	SIPH gradually tapering. R IV+V 1.25-1.5 × HT II. ANT PT/BASE 4.2-6.1	…..7
7	ANT PT/BASE 4.9-6.1 (Al. emigrant with sec. rhin. distributed ANT III 60-83, IV 36-42, V 13-22)	…..Ovatus insitus
–	ANT PT/BASE 4.2-5.3. (Al. emigrant with sec. rhin. distributed ANT III 48-60, IV 26-38, V 10-15)	…..Ovatus sp. (?malicolens) Korea, BMNH collection)
8	SIPH with a subapical zone of polygonal reticulation. ANT tubercles very well developed. ANT III with 1-10 rhinaria. Body spindle-shaped	…..9
–	SIPH without polygonal reticulation. ANT tubercles weakly developed or absent. ANT III without rhinaria. Body ovate	…..10
9	SIPH swollen on distal half, proximal to reticulated part. Hairs on ANT III all less than 0.4 × BD III	…..Illinoia macgillivrayae
–	SIPH cylindrical on distal half (sometimes with some constriction of reticulated part). Hairs on ANT III 0.6-1.0 × BD III	…..Macrosiphum euphorbiae
10	Cauda tongue- or finger-shaped, clearly longer than its basal width. (Al. without a black dorsal abdominal patch)	.….11
–	Cauda short, helmet-shaped or triangular, not longer than its basal width in dorsal view. (Al. with an extensive black dorsal abdominal patch)	…..20
11	Abdomen without any marginal tubercles (MTu). SIPH thin and cylindrical with a small flange, 1.1-1.3 × the very thick cauda which bears 6-7 hairs	…..Schizaphis chaenometicola

–	Abdomen with MTu at least on ABD TERG 1 and 7. SIPH and cauda not as above	…..12
12	SIPH slightly swollen subapically and constricted before the well-developed flange. MTu on ABD TERG 7 placed posteriodorsally to spiracle, and no larger than spiracular aperture	…..Rhopalosiphum oxyacanthae
–	SIPH tapering from base to flange, which is only moderately developed. MTu on ABD TERG 7 placed posterioventrally to spiracle, and usually larger than the spiracular aperture	…..13
13	Stridulatory apparatus present. ANT PT/BASE 3.5-5.0	…..14
–	No stridulatory apparatus. ANT PT/BASE less than 3.5	…..15
14	Longest hairs on ANT III 12-27 μm long, 0.5-1.0 × BD III. Longest hairs on hind tibia up to 60 μm long, less than 0.6 × HT II. Cauda with 10-26 hairs (rarely more than 20). BL often less than 2 mm	…..Aphis (Toxoptera) aurantii
–	Longest hairs on ANT III 29-64 μm long, 1.5-2.0 × BD III. Longest hairs on hind tibia up to 80-110 μm long, 0.7-1.0 × HT II. Cauda with 19-54 hairs (rarely less than 25). BL usually more than 2 mm	….. Aphis (Toxoptera) citricidus
15	Dorsal abdomen almost wholly covered by an extensive solid black sclerite. Cauda black and usually bearing 4-7 hairs	…..Aphis craccivora
–	Dorsal abdomen without an extensive solid black sclerite. Cauda if black then usually with more hairs	…..16
16	Femoral hairs mostly much shorter than trochantro-femoral suture	…..17
–	Femoral hairs long and fine, many exceeding length of trochantro-femoral suture	…..18
17	SIPH 1.3-2.5 × the pale or dusky cauda, which bears 4-8 hairs. R IV+V 1.1-1.4 × HT II. Dorsal abdomen without dark markings	…..Aphis gossypii
–	SIPH and cauda both similarly dark, SIPH being 0.7-1.1 × cauda, which bears 7-17 hairs. R IV+V 0.7-0.9 × HT II. Dorsal abdomen usually with dark markings	…..Aphis spiraephaga
18	ABD TERG 7 and 8 with dark transverse bands, and at least some dark spinopleural markings on abdomen anterior to SIPH	…..Aphis fabae
–	No dark dorsal abdominal markings	…..19
19	MTu usually present on ABD TERG 2-4. Cauda with 10-19 hairs. R IV+V more than 120 mm	…..Aphis pomi
–	MTu usually absent from ABD TERG 2-4. Cauda with 7-15 hairs (rarely more than 12). R IV+V less than 120 mm	…..Aphis spiraecola
20	Spiracles large and rounded. Abdomen with MTu irregularly present, always smaller than spiracular apertures. (Al.with 13-46 rhinaria on ANT III and 0-15 on IV)	…..Brachycaudus helichrysi
–	Spiracles reniform, not large. Abdomen with MTu on most segments, larger than spiracular apertures. (Al. with ANT III and basal part of IV swollen with numerous large rhinaria; 40-60 on III and 18-30 on IV)	…..Dysaphis sp. (Japan; Stroyan, 1985 and BMNH collection)

Chaerophyllum	Apiaceae
Chaerophyllum aromaticum	Aphis fabae; Cavariella aegopodii; Dysaphis chaerophylli;
	Hyadaphis foeniculi; Macrosiphum gei; Myzus persicae
Ch. aureum	Aphis fabae; Aulacorthum solani;
	Cavariella aegopodii, theobaldi;
	Dysaphis caucasica, chaerophyllina; Hyadaphis foeniculi;
	Macrosiphum gei
Ch. bulbosum (incl. ssp. prescotti)	Aphis brohmeri, fabae;
	Cavariella aegopodii, archangelicae, pastinacae;
	Dysaphis brachycyclica, chaerophylli, chaerophyllina, flava;
	Hyadaphis coriandri, foenicuili, galaganiae;
	Macrosiphum gei
Ch. hirsutum	Aphis fabae, gossypii, solanella; Aulacorthum solani;
	Cavariella aegopodii, pastinacae, theobaldi;
	Dysaphis brachycyclica, chaerophylli; Hyadaphis foeniculi;
	Macrosiphum gei; Myzus ornatus, persicae;
	[Semiaphis dauci]
Ch. maculatum	Dysaphis chaerophyllina
Ch. prescotti see bulbosum
Ch. roseum	Myzus persicae
Ch. sylvestre	Cavariella aegopodii; Macrosiphum euphorbiae, gei
Ch. temulentum = Ch. temulum
Ch. temulum	Aphis fabae; Cavariella aegopodii, pastinacae;
	Dysaphis [apiifolia], brachycyclica, chaerophylli, [crataegi];
	Macrosiphum gei; Semiaphis anthrisci
Ch. villarsii	Macrosiphum gei

Key to apterae on Chaerophyllum:-

1	ABD TERG 8 with a backwardly directed process above cauda	…..Cavariella spp. (use couplets 2-14 of key to apterae on Angelica)
–	No supracaudal process	…..2
2	ANT tubercles low or absent	…..3
–	ANT tubercles well developed, greatly exceeding height of middle of front of head in dorsal view	…..12
3	SIPH very short, only 0.4-0.6 × cauda, and flangeless	…..Semiaphis anthrisci
–	SIPH more than 0.8 × cauda, with a distinct flange	…..4
4	Cauda helmet-shaped, not longer than its basal width in dorsal view	…..5
–	Cauda tongue-shaped, much longer than its basal width	…..8
5	ANT III with short blunt hairs maximally 12-13 mm long, 0.6-0.7 × BD III. R IV+V 1.5-1.6 × HT II	…..Dysaphis caucasica*
–	ANT III with pointed hairs maximally 22-74 mm long, 1.1-3.1 × BD III. R IV+V 1.1-1.35 × HT II	…..6
6	ABD TERG 8 with 4-6 hairs (very rarely 7), and cauda with 4-5 hairs (rarely 6). Marginal tubercles (MTu) usually absent from ABD TERG 6	…..Dysaphis chaerophyllina*
–	ABD TERG 8 with 5-16 hairs; if less than 8 then MTu are usually present on ABD TERG 6. Cauda with 4-13 hairs	…..7
7	Hairs on ANT III are maximally 47-67 mm long, 2.1-3.1 × BD III	…..Dysaphis chaerophylli
–	Hairs on ANT III are maximally 22-42 mm long, 1.1-1.9 × BD III	…..Dysaphis flava or brachycyclica
8	SIPH gradually tapering, 0.8-2.1 × cauda, which bears 4-31 hairs	…..9
–	SIPH swollen, 0.6-1.3 × cauda, which bears 5-7 hairs	…..11
9	Cauda distinctly paler than SIPH, and bearing 4-8 hairs	…..Aphis gossypii
–	Cauda as dark as SIPH, and bearing 11-31 hairs	…..10
10	Cauda with 11-24 hairs. ABD TERG 8 with 2-5(-7) hairs. ABD TERG 2-6 bearing a total of 0-3 small MTu	…..Aphis fabae
–	Cauda with 20-31 hairs. ABD TERG 8 with 5-12 hairs. ABD TERG 2-6 bearing a total of 5-9 often rather large MTu	…..Aphis brohmeri
11	SIPH clavate, 1.7-3.2 × R IV+V, 1.6-2.8 × HT II and 0.9-1.3 × cauda	…..Hyadaphis foeniculi
–	SIPH swollen basally, 0.95-1.7 × R IV+V, 0.9-1.35 × HT II and 0.6-0.8 × cauda	…..Hyadaphis galaganiae (or coriandri)

12	SIPH with a subapical zone of polygonal reticulation. ANT tubercles smooth, divergent, bearing pointed hairs	…..13
–	SIPH without polygonal reticulation. ANT tubercles spiculose or scabrous, steep-sided or apically convergent, bearing blunt hairs	…..14
13	Longest hair on ABD TERG 8 is 38-63 µm, 0.6-1.4 × ANT BD III. Anterior half of subgenital plate usually (77%) with only 2 hairs (18% with 3, 5% with 4-6 hairs)	…..Macrosiphum euphorbiae
–	Longest hair on ABD TERG 8 is 66-106 µm, 1.4-2.0 × ANT BD III. Anterior half of subgenital plate with 2-11 hairs, usually (77%) with 4-8 hairs	…..Macrosiphum gei
14	ANT III usually with 1-2 rhinaria. Inner faces of ANT tubercles spiculose, approximately parallel	…..Aulacorthum solani
–	ANT III without rhinaria. Inner faces of ANT tubercles scabrous, convergent apically	…..15
15	Dorsum with a pattern of dark intersegmental ornamentation. ANT PT/BASE 1.7-2.8. SIPH tapering, with a slight “S”-curve	…..Myzus ornatus
–	Dorsum without dark intersegmental ornamentation. ANT PT/BASE 2.8-4.7. SIPH slightly clavate	…..Myzus persicae

Chaetochloa see Setaria

Poaceae

Chaetotropis see Polypogon

Poaceae

Chalcas see Murraya	Rutaceae

Chamaebatia	Rosaceae
Chamaebatia foliolosa	Ericaphis voegtlini; Macrosiphum euphorbiae

Couplet for separating apterae of these two species:-

(Both species have smooth head and SIPH with subapical polygonal reticulation.)

–	R IV+V 1.5-1.8 × HT II. Median frontal tubercle developed similarly to ANT tubercles so that front of head is W-shaped in dorsal view. SIPH slightly swollen, pale basally and dark distally. Cauda with 4-6 hairs	…..Ericaphis voegtlini
–	R IV+V 0.8-1.2 × HT II. Median frontal tubercle undeveloped, ANT tubercles well developed, with divergent inner faces. SIPH tapering/cylindrical, pale or only dusky towards apices. Cauda with 8-12 hairs	…..Macrosiphum euphorbiae

Chamaebatiaria	Rosaceae
Chamaebatiaria millefolium	Acyrthosiphon sp. near pseudodirhodum (BMNH collection),
	Illinoia sp. (BMNH collection)

(Both the species in the BMNH collection are from USA, California, White Mts., Cotton Wood Basin, 9, 600 ft, leg. P Rude)

Couplet for separating apterae of the two species from Chamaebatiaria in the BMNH collection:-

(Both have smooth head with divergent ANT tubercles, and mainly pale SIPH and cauda.)

–	SIPH c.1.1 × cauda which bears c.14 hairs. ANT PT/BASE c.6, PT 2.8-3.0 × SIPH. R IV+V 0.9-1.0 × HT II	….. Acyrthosiphon sp. near pseudodirhodum
–	SIPH 2.3-2.8 × cauda which bears 8-10 hairs. ANT PT/BASE 3.3-3.9, PT 0.45-0.6 × SIPH. R IV+V 1.6-2.0 × HT II	…..Illinoia sp. (BMNH collection)

Chamaecrista	Fabaceae
Chamaecrista absus	Aphis (Toxoptera) citricidus
Ch. mimosoides	Aphis craccivora, gossypii
Ch. nomane	Aphis craccivora

Use key to polyphagous aphids.

Chamaecyparis	Cupressaceae
Chamaecyparis lawsoniana	Cinara (Cedrobium) laportei;
	Cinara (Cupressobium) cupressi, louisianensis, tujafilina;
	Illinoia morrisoni
Ch. obtusa	[Cinara ozawai]; Stomaphis hirukawai
Ch. thyroides	[Cinara sp. (Leonard, 1968: 269, 340)]

Key to aphids on Chamaecyparis:-

1	ANT PT/BASE more than 1. SIPH long and tubular, swollen distally …..Illinoia morrisoni
–	ANT PT/BASE less than 1. SIPH are broad, hairy cones	…..2
2	Rostrum about 1.7 × BL	…..Stomaphis hirukawai
–	Rostrum shorter than BL	…..3
3	Antenna 5-segmented. Dorsal hairs of aptera club-shaped, ornamented with numerous barbules	…..Cinara (Cedrobium) laportei
–	Antenna 6-segmented. Dorsal hairs normal, pointed	….. Cinara (Cupressobium) spp.
	(use couplets 5-7 of key under Cupressus)

(N.B. Other aphids whose more normal hosts are Cedrus, Cupressus ot Tsuga may occasionally colonise Chamaecyparis, so it may be advisable to look also at the keys to aphids on those plants.)

Chamaecytisus	Fabaceae
Chamaecytisus albus = Cytisus albus
Ch. austriacus = Cytisus austriacus
Ch. candicans = Genista monspessulana
Ch. heuffelii = Cytisus austriacus ssp. heuffelii
Ch. palmensis = Cytisus proliferus
Ch. proliferus = Cytisus proliferus
Ch. ratisbonensis = Cytisus ratisbonensis
Ch. ruthenicus = Cytisus ruthenicus
Ch. scrobiszewskii = Cytisus graniticus
Ch. spinosus = Cytisus spinosus
Ch. supinus = Cytisus hirsutus
Ch. zingeri = Cytisus ruthenicus var. zingeri

Use key to apterae on Cytisus.

Chamaedaphne	Ericaceae
Chamaedaphne calyculata	Macrosiphum nasonovi

Chamaedorea	Arecaceae
Chamaedorea costaricana	Cerataphis brasiliensis
Ch. elegans	Rhopalosiphum padi

Use key to apterae on palms under Calamus.

Chamaegeron	Asteraceae
Chamaegeron oligocephalus	Uroleucon tschuensis

Chamaemelum	Asteraceae
Chamaemelum fuscatum	Brachycaudus helichrysi; Macrosiphum euphorbiae;
	Myzus persicae
Ch. mixtum = Cladanthus mixtus
Ch. nobile	Aphis craccivora, fabae; Brachycaudus cardui, helichrysi;
	Macrosiphoniella sanborni, tanacetaria; Myzus persicae

Use key to apterae on Anthemis.

Chamaenerion see Epilobium

Onagraceae

Chamaerhodos	Rosaceae
Chamaerhodos erecta	Szelegiewicziella chamaerhodi

Chamaerops	Arecaceae
Chamaerops humilis	Cerataphis brasiliensis

Use key to apterae on palms under Calamus.

Chamaespartium	Fabaceae
Chamaespartium sagittale = Genista sagittalis
Ch. tridentatum	Aphis craccivora

Chamaesyce	Euphorbiaceae
Chamaesyce maculata = Euphorbia maculata

Chamelaucium	Myrtaceae
Chamelaucium uncinatum	Aphis gossypii, spiraecola; Myzus persicae

Use key to polyphagous aphids.

Chamissoa	Amaranthaceae
Chamissoa altissima	Aphis craccivora, gossypii; Macrosiphum euphorbiae

Use key to polyphagous aphids.

Chamomilla	Asteraceae
Chamomilla recutita = Matricaria chamomilla
Ch. suaveolens = Matricaria matricarioides
Ch. tenuifolia = Tripleurospermum tenuifolium

Changium	Apiaceae
Changium smyrnoides	Semiaphis heraclei

Chaptalia	Asteraceae
Ch. comptonioides	Aphis aurantii, gossypii, spiraecola
Ch. montana	Aphis aurantii, gossypii; Uroleucon ambrosiae
Ch. nutans	Aphis [coreopsidis], gossypii
Chaptalia sp.	Brachycaudus helichrysi

Use key to polyphagous aphids.

Chardinia	Asteraceae
Ch. orientalis	Aphis craccivora