C_HOSTS_Seq_Sop – Blackman & Eastop's Aphids on the World's Plants

–	ANT PT/BASE less than 0.5. SIPH as large dark hairy cones	…..Cinara cupressi
–	ANT PT/BASE 3.7-4.4. SIPH tubular and swollen on distal half	…..Illinoia morrisoni

*Sequoiadendron*	Taxodiaceae
*Sequoiadendron giganteum*	Illinoia morrisoni

*Serapias*	Orchidaceae
*Serapias vomeracea*	Aphis fabae

*Seriphidium*	Asteraceae
Seriphidium amoenum	Macrosiphoniella seriphidii
S. aucheri	Coloradoa heinzei; Macrosiphoniella vallesiacae
S. balchanorum = Artemisia balchanorum
S. baldshuanicum = Artemisia baldshuanica
S. brevifolium	Coloradoa submissa
S. canum = Artemisia cana
S. cinum	Cryptosiphum astrachanicae;
	Macrosiphoniella atra, kirgisica, seriphidii, terraealbae;
	Protrama flavescens; Rectinasus buxtoni;
	Xerobion alakuli, cinae
S. ferganense =Artemisia ferganensis
S. glanduligerum = Artemisia glanduligera
S. gurganicum	Macrosiphoniella kirgisica, seriphidii; Xerobion cinae
S. halophilum = Artemisia halophila
S. heptapotamicum	Coloradoa heinzei, mesasiatica;
	Macrosiphoniella kirgisica, seriphidii;
	Obtusicauda moldavica; Xerobion cinae
S. herba-album = Artemisia herba-alba
S. junceum	Coloradoa heinzei; Macrosiphoniella kirgisica, seriphidii; Protaphis miranda; Xerobion alakuli
S. karatavicum	Macrosiphoniella kirgisica, seriphidii; Protaphis miranda;
	Xerobion cinae
S. kaschgaricum	Macrosiphoniella seriphidii
S. lerheanum *(lercheanum?)*	Coloradoa heinzei; Cryptosiphum astrachanicae;
	Macrosiphoniella kirgisica, pulvera, seriphidii;
	Protaphis miranda; Xerobion cinae
S. maritimum	[Aphis commoda Walker – nomen dubium];
	Brachycaudus helichrysi; Coloradoa heinzei, submissa;
	Cryptosiphum artemisiae, caspicae;
	[Diuraphis frequens]; [Geoica utricularia];
	Macrosiphoniella abrotani, absinthii, atra ssp, latysiphon,
	austriacae, procerae, pulvera;
	Pleotrichophorus glandulosus; Protaphis miranda;
	Xerobion cinae
S. nitrosum = Artemisia nitrosa
S. nutans = Artemisia nutans
S. pauciflorum = Artemisia pauciflora
S. porrectum = Artemisia porrecta
*S. rhodanthum* = Artemisia rhodantha
S. rigidum = Artemisia rigida
S. santolinum	Coloradoa heinzei, [Coloradoa sp. (Kadyrbekov 2002d)];
	Macrosiphoniella kirgisica, seriphidii, szalaymarszoi,
	terraealbae;
	Xerobion alakuli, cinae
S. santonicum = Artemisia santonica
S. schrenkianum	Coloradoa heinzei; Cryptosiphum astrachanicae;
	Macrosiphoniella kirgisica, pulvera, seriphidii,
	szalaymarzsoi, terraealbae;
	Obtusicauda moldavica;
	Protaphis elatior, elongata, miranda; Xerobion cinae
S. scopiforme	Xerobion cinae
S. sieberi	[Hyperomyzus lactucae];
	Macrosiphoniella kermanensis, seriphidii, vallesiacae;
	Obtusicauda iranica; [Protaphis iliensis]
S. sublessingianum	[Brachunguis sp. (Juchnevitch 1968)];
	Coloradoa heinzei, mesasiatica;
	Cryptosiphum astrachanicae;
	Macrosiphoniella kirgisica, pulvera, seriphidii,
	sieversianae, szalaymarzsoi, terraealbae;
	Obtusicauda moldavica;
	Protaphis elatior, miranda; Xerobion alakuli, cinae
S. tauricum = Artemisia taurica
S. tenuisectum = Artemisia tenuisecta
S. terrae-albae = Artemisia terrae-albae
S. tianschanicum	Xerobion cinae
S. tridentatum = Artemisia tridentata
S. turanicum = Artemisia turanica
S. validum = Artemisia valida
S. vallesiacum = Artemisia vallesiaca
See Artemisia for a combined key to apterae on Artemisia and Seriphidium.

*Serissa*	Rubiaceae
*Serissa japonica*	Aphis gossypii, serissae; Neomyzus circumflexus;
	Pseudomegoura magnoliae

Key to apterae on Serissa:-

–	ANT 5-segmented. SIPH a lttle shorter than cauda	…..Aphis serissae*
–	Without that combination of characters	…..go to key to polyphagous aphids

*Serjania*	Sapindaceae
*Serjania diversifolia*	Aphis spiraecola
S. polyphylla	Aphis spiraecola
S. subdentata	Aphis craccivora, gossypii
S. triquetra	Aphis spiraecola

Use key to polyphagous aphids.

*Serratula*	Asteraceae
*Serratula arvensis* see Cirsium arvense
S. cardunculus	Aphis fabae; Uroleuconminor
*S. centauroides*	Uroleucon mongolicum
S. coronata	Aphis fabae, serratularadicis;
	Uroleucon giganteum, jaceae, minor
S. gmelinii	Uroleucon minor
S. kirghisorum	Aphis craccivora
S. nudicaulis	Brachycaudus cardui
S. quinquefolia	Brachycaudus helichrysi; Uroleucon capsicum
S. radiata	Uroleucon minor
*S. tinctoria* (incl. ssp. monticola)	Aulacorthum solani; Brachycaudus helichrysi;
	Uroleucon minor
*S. wolffii* = S. coronata
Serratula sp.	[Uroleucon sonchi]

Key to apterae on Serratula:-

1	ANT 5-segmented. Prothorax and ABD TERG 2-4 as well as 1 and 7 all with well-developed hemispherical marginal tubercles. R IV+V 1.5-1.7 × HT II and bearing 2-4 accessory hairs. SIPH 0.9-1.1 × cauda, both shorter than R IV+V. Cauda triangular with 6-8 hairs	…..Aphis serratularadicis*
–	ANT usually 6-segmented. MTu either absent or only consistently present on prothorax and ABD TERG 1 and 7, and other characters not in the above combination	…..2
2	SIPH dark with a distal zone of polygonal reticulation	…..3
–	SIPH pale or dark, but if dark then without polygonal reticulation	…..go to key to polyphagous aphids

3	Cauda as dark as, or almost as dark as, SIPH	…..4
–	Cauda much paler than SIPH	…..6
4	Cauda with c.40-60 hairs. R IV+V 1.4-1.7 × HT II. ANT III with 22-66 rhinaria	…..Uroleucon giganteum

–	Cauda with 13-28 hairs. R IV+V 1.1-1.4 × HT II. ANT III with 15-54 rhinaria	…..5
5	Cauda with 13-24 hairs. ANT III with 15-21 rhinaria	…..Uroleucon minor
–	Cauda with 22-28 hairs. ANT III with 16-54 rhinaria	…..Uroleucon jaceae
6	Cauda with 7-11 hairs. First tarsal segments with 3 hairs. Hind tibia without a row of peg-like hairs	…..Uroleucon mongolicum
–	Cauda with 24-41 hairs. First tarsal segments with 5 hairs. Hind tibia with a row of peg-like hairs	…..Uroleucon caspicum

*Sesamum*	Pedaliaceae
*Sesamum indicum*	Aphis craccivora, gossypii, nasturtii;
	Macrosiphum euphorbiae; Myzus ornatus, persicae
S. orientale = S. indicum
S. radiatum	Aphis gossypii

Use key to polyphagous aphids.

*Sesbania* (including Daubetonia)	Fabaceae
*S. aculeata* = S. bispinosa
S. aegyptiaca = S. sesban
S. bispinosa	Aphis craccivora
S. coerulescens	Aphis craccivora
*S. grandiflora*	Acyrthosiphon gossypii, pisum; Aphis gossypii
S. macrantha	Sitobion sp. (Millar 1994)
*S. punicea*	Aphis craccivora; Myzus persicae
S. sesban	Aphis craccivora; Macrosiphum euphorbiae;
	Myzus persicae
S. tripetii = S. punicea

Key to apterae on Sesbania:-

1	ANT tubercles very well developed, with smooth divergent inner faces. SIPH pale and attenuated distally, thinner than hind tibiae at their respective midpoints	…..2
–	ANT tubercles variably developed. SIPH pale or dark, and thicker than hind tibiae at their respective midpoints	…..3
2	SIPH 0.42-0.50 × BL and 2.5-3.5 × cauda	…..Acyrthosiphon gossypii
–	SIPH 0.22-0.37 × BL and 1.2-1.9 × cauda	…..Acyrthosiphon pisum
3	SIPH with distal band of polygonal reticulation and hairs on ANT III less than 0.5 × BD III	…..Sitobion sp. (Millar 1994)
–	SIPH either without a distal band of polygonal reticulation or hairs on ANT III more than 0.5 × BD III	…..go to key to polyphagous aphids

*Seseli*	Apiaceae
*Seseli annuum*	Anuraphis pyrilaseri;
	Aphis fabae, seselii, umbelliferarum;
	Semiaphis dauci ssp. seselii
*S. austriacum* = S. elatum ssp. austriacum
S. buchtormense = Libanotis buchtormensis
S. campestre	Defractosiphon brevisiphon
S. condensatum = Libanotis condensata
S. coronatum	Dysaphis foeniculus
S. devenyense	Semiaphis dauci ssp. seselii
*S. dichotomum*	Dysaphis seselii
S. elatum	Acyrthosiphon nigripes ssp. blattnyi; Aphis fabae;
	Defractosiphon brevisiphon; Macrosiphum gei;
	Semiaphis dauci ssp. seselii
S. elatum ssp. austriacum	Acyrthosiphon nigripes ssp. blattnyi;
	Aphis fabae, franzi, solanella, [spiraephaga];
	Cavariella aegopodii; Defractosiphon franzi;
	Semiaphis dauci ssp. seselii
S. elatum ssp. osseum	Acyrthosiphon nigripes ssp. blattnyi; Aphis schilderi;
	Defractosiphon brevisiphon;
	Semiaphis dauci, dauci ssp. seselii
*S. glabratum*	Aphis franzi; Cavariella aegopodii; Semiaphis dauci
S. hippomarathrum	Acyrthosiphon nigripes; Semiaphis dauci ssp. seselii
*S. incanum* =	Libanotis incana
S. ledebourii	Aphis brohmeri, franzi, grosmannae; Cavariella aegopodii;
	Hyadaphis coriandri; Semiaphis dauci
S. ledebouriana (?)	Cavariella aegopodii
S. leucospermum	Acyrthosiphon nigripes ssp. blattnyi
*S. libanotis*	Aphis fabae, franzi, podagrariae, seselii;
	Cavariella aegopodii;
	Dysaphis [crataegi], foeniculus, libanotidis;
	Semiaphis dauci ssp. seselii
S. montanum	Aphis fabae
S. nanum	Aphis fabae
S. osseum = S. elatum ssp. osseum
*S. pallasii* = S. varium
S. schrenkianum = Libanotis schrenkiana
S. seseloides = Libanotis seseloides
S. sessiliflorum	Cavariella aegopodii; Dysaphis foeniculus;
	Hyadaphis coriandri; Semiaphis dauci, [sphondylii]
S. sibiricum	[Semiaphis sphondylii]
S. stricta	Aphis franzi
S. tortuosum	Aphis schilderi, seselii; Semiaphis dauci ssp. seselii
S. transcaucasicum	Aphis fabae, umbelliferarum
S. unicaule	Dysaphis unicauli
S. varium	Hyadaphis foeniculi; Semiaphis dauci ssp. seselii
Seseli spp.	[Aphis seselii Lichtenstein (nomen nudum)];
	Dysaphis viennoti; Semiaphis anthrisci

Key to apterae on Seseli (and Libanotis):-

1	ANT tubercles well developed, with inner faces smooth and divergent	…..2
–	ANT tubercles undeveloped or weakly developed, not projecting beyond middle part of head in dorsal view	…..3
2	Head, ANT and legs almost entirely black. SIPH long, thin and black, without subapical reticulation. ANT III with 9-26 rhinaria	…..Acyrthosiphon nigripes ssp. blattnyi
–	Head pale; ANT, legs and SIPH only partly dark. SIPH with subapical poygonal reticulation. ANT III with 1-10 rhinaria	…..Macrosiphum gei
3	ABD TERG 8 with a posteriorly projecting process above cauda. SIPH clavate, 0.17-0.23 × BL and 1.8-2.5 × cauda. ANT PT/BASE 0.64-1.25	…..Cavariella aegopodii
–	No supracaudal process. SIPH cylindrical or tapering, or if clavate then shorter and/or ANT PT longer	…..4
4	Cauda helmet-shaped or triangular, less than 1.1 × its basal width in dorsal view	…..5
–	Cauda elongate triangular or tongue-shaped, nore than 1.2 × its basal width	…..13
5	SIPH longer than cauda, which is helmet-shaped (pentagonal). ANT III-IV without rhinaria	…..6

–	SIPH 0.3-0.6 × cauda, which is triangular. Rhinaria present on ANT III, and sometimes on IV	…..12
6	Head densely spiculose. SIPH shorter than R IV+V, with close-set annular rows of blunt spinules. Cauda with 10-12 hairs. Spinal tubercles (STu) present on ABD TERG 1-5	…..Anuraphis pyrilaseri
–	Head not spiculose. SIPH longer than R IV+V, normally imbricated. Cauda with 5-8 hairs. STu absent from ABD TERG 1-5; present on head and ABD TERG 8, or absent	…..7
7	STu present on head, and often also on ABD TERG 8, or 7 and 8	…..8
–	STu absent	…..11
8	Longest hairs on ANT III (0.8-)1.0-3.3 × BD III	…..9
–	Longest hairs on ANT III 0.4-0.8 × BD III	…..10
9	Longest hairs on ANT III (0.8-)1.0-1.6 × BD III. SIPH 0.10-0.15 mm	….. Dysaphis foeniculus
–	Longest hairs on ANT III 2.0-3.3 × BD III. SIPH 0.14-0.21 mm	….. Dysaphis mordvilkoi*
10	Marginal tubercles (MTu) present on ABD TERG 7 (as well as 1-5). SIPH up to 0.14 × BL	…..Dysaphis libanotidis*
–	MTu only present on ABD 7 in a minority (12.7%) of specimens. SIPH c. 0.11 × BL	…..Dysaphis seselii*

11	ANT 0.33-0.5 × BL. SIPH 0.07-0.08 × BL	…..Dysaphis unicauli*
–	ANT 0.69-0.85 × BL. SIPH 0.09-0.11 × BL	…..Dysaphis viennoti
12	Flat or hemispherical marginal tubercles (MTu) consistently present on ABD TERG 1-5 and 7	…..Aphis umbelliferarum
–	MTu absent or inconspicuous, or not consistently present on any of ABD TERG 1-7	…..Aphis seselii*

13	MTu present on prothorax and (at least) ABD TERG 1 and 7	…..14
–	MTu present or absent, but not on ABD TERG 1 and 7	…..19
14	MTu consistently present on ABD TERG 2-4 (-5) as well as 1 and 7	…..15
–	MTu consistently on ABD TERG 1 and 7, but only irregularly on 2-5	…..17
15	SIPH 0.6-0.8 × cauda, which bears 6-9 hairs. ANT PT/BASE 1.6-2.0. R IV+V 0.8-0.95 × HT II	…..Aphis franzi
–	SIPH 1.0-1.6 × cauda, which bears 12-31 hairs. ANT PT/BASE 2.3-3.3. R IV+V 1.0-1.3 × HT II	…..16
16	Longest hairs on ANT III 1.7-2.8 × BD III. Cauda with 20-31 hairs	…..Aphis brohmeri
–	Longest hairs on ANT III 0.4-0.6 × BD III. Cauda with 11-19 hairs	…..Aphis grosmannae
17	Cauda with 4-8 hairs. Longest hairs on ANT III 0.25-0.5 × BD III	…..Aphis schilderi
–	Cauda with 8-24 hairs. Longest hairs on ANT III 0.8-3.6 × BD III	…..18
18	Longest hairs on ANT III 2.0-3.6 × ANT III	…..Aphis podagrariae
–	Longest hairs on ANT III 0.6-2.2 × ANT III	…..Aphis fabae (or solanella)
19	SIPH 0.6-1.4 × cauda, swollen for part of length, with a large terminal aperture and a well-developed flange	…..20
–	SIPH 0.12-0.9 × cauda, tapering or cylindrical, flangeless, with a small aperture	…..21
20	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, 0.6-0.8 × cauda and 0.9-1.3 × HT II	…..Hyadaphis coriandri
21	SIPH 0.75-0.9 × cauda, tapering, with a narrow rounded apex and small subterminal aperture. ANT III with 0-6 rhinaria on distal part, and IV with 1-7 (1-11 on III + IV if fused)	…..Defractosiphon franzi

–	SIPH 0.12-0.6 × cauda, either very short and conical, or cylindrical with a terminal aperture. ANT III-IV with or without rhinaria	…..22
22	SIPH very short, 0.12-0.2 × cauda, mammariform or conical, shorter than basal width, with a small subapical aperture	…..Defractosiphon brevisiphon
–	SIPH 0.4-0.6 × cauda, longer than their basal widths, with terminal aperture	…..23
23	Posterior hair on hind trochanter less than 0.5 × diameter of trochantro-femoral suture	…..Semiaphis dauci (incl. ssp. seselii)
–	Posterior hair on hind trochanter more than 0.6 × diameter of trochantro-femoral suture	…..24

24	SIPH cylindrical or slightly swollen, more than 1.5 × their basal width. ABD TERG 2-4 often with small hemispherical MTu	…..Semiaphis anthrisci
–	SIPH tapering, less than 1.5 × their basal width. MTu absent or rare	…..Semiaphis heraclei

*Sesleria*	Poaceae
*Sesleria albicans*	Sitobion avenae
*S. coerulea*	Anoecia corni; Paracletus cimiciformis; Tetraneura ulmi
S. varia = S. coerulea

Use key to apterae on grasses under Digitaria.

*Setaria* (including Chaetochloa)	Poaceae
Setaria aurea = S. sphacelata
S. barbata	Geoica lucifuga; Tetraneura fusiformis
S. chevalieri = S. megaphylla	Aphis (Toxoptera) aurantii
S. chondrachne	Colopha setaricola
S. faberi	Rhopalosiphum maidis
S. geniculata = S. parviflora
S. glauca = Pennisetum glaucum
*S. imberbis* = S. parviflora
S. incrassata	Rhopalosiphum maidis
S. intermedia	Tetraneura fusiformis
S. italica	Anoecia corni; Melanaphis sacchari;
	Paracletus cimiciformis;
	Rhopalosiphum maidis, padi, rufiabdominale;
	Schizaphis graminum; Sipha elegans, flava;
	Sitobion avenae, miscanthi;
	Tetraneura caerulescens, fusiformis, javensis,
	nigriabdominalis, yezoensis
*S. lutescens* = S. pumila
*S. macrostachya*	Pseudoregma panicola
S. megaphylla	Aphis (Toxoptera) aurantii; Geoica lucifuga;
	[Sitobion sp. (Millar 1994)]; Tetraneura fusiformis
S. pallide-fusca = S. pumila
S. palmifolia	Ceratovacuna panici; Geoica lucifuga;
	Hysteroneura setariae; Sitobion miscanthi;
	Smynthurodes betae
*S. paniculifera* = S. palmifolia
S. parviflora	Aphis fabae; Carolinaia howardii, setariae;
	Hysteroneura setariae; Rhopalosiphum maidis;
	Sipha flava; Sitobion avenae, miscanthi, pauliani;
	Tetraneura fusiformis
*S. phleoides* = S. incrassata
*S. plicata*	Hysteroneura setariae; Rhopalosiphum maidis;
	Sitobion lambersi
S. poiretiana	Sitobion africanum
S. pumila	Anoecia corni, fulviabdominalis, haupti, vagans;
	Aphis gossypii; [Dysaphis microsiphon];
	Geoica lucifuga, setulosa, utricularia; Myzus ornatus;
	Rhopalosiphum maidis, padi, rufiabdominale;
	Schizaphis graminum; Sipha elegans, flava, maydis;
	Sitobion akebiae, avenae, miscanthi;
	Tetraneura basui, caerulescens, fusiformis, radicicola,
	ulmi
S. sphacelata (incl. vars aurea, splendida)	Hysteroneura setariae; Rhopalosiphum maidis;
	Sipha flava;
	Sitobion africanum, graminis, pauliani,
	[Sitobion sp. (Millar 1994)];
	Tetraneura fusiformis
S. tenuifolia (?)	Sitobion africanum
S. trinervia = S. sphacelata
S. verticillata	Anoecia corni, vagans; Aphis gossypii;
	Geoica utricularia; Hysteroneura setariae;
	Rhopalosiphum maidis; Sipha elegans, flava, maydis;
	Sitobion africanum, avenae;
	Tetraneura caerulescens, fusiformis, [longisetosa],
	nigriabdominalis, ulmi
S. viridis	Anoecia corni, cornicola, fulviabdominalis, vagans;
	Aphis gossypii; Diuraphis noxia; Forda marginata;
	Geoica utricularia; Hyalopterus pruni;
	Hysteroneura setariae; [Kaltenbachiella nirecola];
	Myzus persicae; Paracletus bykovi, cimiciformis;
	Protaphis middletonii;
	Rhopalosiphum maidis, padi, rufiabdominale;
	Schizaphis graminum; Sipha elegans, flava, maydis;
	Sitobion akebiae, avenae;
	Tetraneura fusiformis, ulmi, yezoensis;
	[Toxoptera setariae Rusanova 1942 (nomen nudum)]
Setaria spp.	Anoecia setariae; Aploneura lentisci;
	Ceratovacuna perglandulosa; Laingia psammae;
	[Myzus maculocorpus]; Pseudaphis sijui;
	[Pyrolachnus imbricatus]; Sitobion bamendae, fragariae
Use key to apterae of grass-feeding aphids under Digitaria.

Setoreasea see Tradescantia

Commelinaceae

*Severinia* see Atalantia	Rutaceae
*Severinia buxifolia* = Atalantia buxifolia

*Shepherdia* (including Lepargyrea)	Elaeagnaceae
Shepherdia argentea	Capitophorus elaeagni, hippophaes, shepherdiae, similis
Sh. canadensis	Capitophorus elaeagni, hudsonicus
Shepherdia sp.	[Capitophorus essigi]

Key to apterae in spring populations on Shepherdia:-

[Note: All five species have thick hairs with expanded apices, arising from tuberculate bases. The key is not applicable to fundatrices. In western North America a sixth species (C. essigi) probably also has Shepherdia as primary host (A. Jensen, pers.comm. and see aphidtrek.org), but its spring generations have not been recorded.]

1	SIPH distinctly swollen subapically on inner side, to more than 1.2 × minimum width basad	…..2
–	SIPH cylindrical or tapering, or only very slightly swollen subapically, to less than 1.1 × minimum width basad	…..4
2	Cauda not longer than R IV+V, and bearing 5 hairs. Dorsal cuticle variolate. ANT PT/BASE 2.0-2.8	…..Capitophorus shepherdiae
–	Cauda much longer than R IV+V, and bearing 6-9 hairs. Dorsal cuticle almost smooth between hair-bases. ANT PT/BASE 2.4-8.9	…..3
3	ANT PT/BASE 5.5-8.9	…..Capitophorus hippophaes
–	ANT PT/BASE 2.4-2.7	…..Capitophorus hudsonicus
4	ABD TERG 1-4 each with 6-8 hairs (usually 1 pair each of spinal, pleural and marginal hairs per tergite). R IV+V 1.4-1.5 × HT II and shorter than cauda which bears 7-11 hairs	…..Capitophorus elaeagni
–	ABD TERG 1-4 each with 2 pairs of spinal and pleural hairs, and usually with 3 marginal hairs on each side. R IV+V 1.9-2.3 × HT II and longer than cauda, which bears 5-6 hairs	…..Capitophorus similis

*Sherardia*	Rubiaceae
*Sherardia arvensis*	Aphis fabae, gossypii; Brachycaudus helichrysi;
	Myzus ascalonicus, cerasi (as veronicae), persicae

Key to apterae on Sherardia:-

–	Dorsal abdomen with an extensive black sclerotic shield. SIPH black, coarsely imbricated, 2.3-2.8 × cauda and 1.3-1.8 × ANT III	…..Myzus cerasi
–	Without that combination of characters	…..go to key to polyphagous aphids

*Sherwoodia*	Diapensiaceae
*Sherwoodia galacifolia*	Amphorophora laingi (? – Leonard 1968)

*Shibataea*	Poaceae
*Shibataea chinensis*	Glyphinaphis bambusae; Pseudoregma alexanderi
*Sh.kumasaca*	Glyphinaphis bambusae; Melanaphis bambusae

(use key to aphids on Bambusa)

Shiiasee Castanopsis

Fagaceae

*Shorea*	Dipterocarpaceae
*Shorea robusta*	Aphis gossypii, nasturtii
*Sh. talura*	Aphis gossypii

Use key to polyphagous aphids.

Shortia see Sherwoodia

Diapensiaceae

*Sibbaldia*	Rosaceae
*Sibbaldia tridentata*	Aphis gossypii

*Sibbaldianthe*	Rosaceae
*Sibbaldianthe bifurca*	Aphis comari, fabae, tianschanica;
(incl. ssp. orientalis)	Macropodaphis rechingeri

(use key to apterae on Potentilla)

*Sibiraea*	Rosaceae
*Sibiraea altaiensis* = S. laevigata
S. laevigata	Acyrthosiphon ignotum; Aphis pomi; Aulacorthum solani

Use key to apterae on Spiraea.

*Sicyos*	Cucurbitaceae
*Sicyos angulata*	Macrosiphum euphorbiae
S. edulis see Sechium edule

*Sida*	Malvaceae
*Sida abutilifolia*	Aphis gossypii
*S. acuminata* = Sidastrum multiflorum
*S. acuta*	Aphis aurantii, gossypii, spiraecola; Myzus persicae
*S. alba* = Sida spinosa
*S. carpinifolia* = Sida acuta
*S. cordifolia*	Aphis fabae, gossypii
S. cunninghamii (?)	Aphis gossypii
S. garckeana = Sida acuta
S. glomerata	Aphis gossypii
*S. palmata*	Aphis gossypii
S. procumbens = Sida abutilifolia
S. pyramidata = Allosidastrum pyramidatum
S. rhombifolia	Aphis gossypii, spiraecola
S. schimperiana	Myzus ornatus, persicae
S. spinosa	Aphis gossypii; Myzus persicae
S. urens	Aphis gossypii
Sida spp.	Aphis citricidus, coreopsidis, nasturtii;
	Aulacorthum solani; [Macrosiphum salviae];
	[Sumatraphis celti]

Key to apterae on Sida:-

–	SIPH 0.24-0.40 × BL, about twice as long as the much paler cauda. Head, ANT I, II and basal part of III very pale, contrasting with dark rest of ANT	..….Aphis coreopsidis
–	Without that combination of characters	…..go to key to polyphagous aphids

*Sidalcea*	Malvaceae
Sidalcea sp.	[Acyrthosiphon pisum]; Uroleucon eoessigi

*Sidastrum*	Malvaceae
*Sidastrum multiflorum*	Aphis gossypii

*Sideritis*	Lamiaceae
Sideritis romana	Aphis origani

*Sideroxylon* (including Mastichodendron, Dipholis)	Sapotaceae
*Sideroxylon foetidissimum*	Aphis (Toxoptera) aurantii
*S. salicifolium*	Aphis (Toxoptera) aurantii

*Sieversia* see Geum	Rosaceae
Sieversia ciliata = Geum triflorum var. ciliatum

*Sigesbeckia*	Asteraceae
*Sigesbeckia glabrescens*	Aulacorthum solani;
	Myzus [siegesbeckiae], siegesbeckicola
*S. jorullensis*	Brachycaudus helichrysi
*S. orientalis* (incl. ssp. pubescens)	Aphis gossypii; Coloradoa rufomaculata;
	Myzus siegesbeckicola; Rhopalosiphoninus tiliae
*Sigesbeckia* sp.	Aphis odinae

Key to apterae on Sigesbeckia:-

1	SIPH black, markedly swollen into a spindle shape on distal two-thirds. Cauda triangular	…..Rhopalosiphoninus tiliae
–	SIPH pale or dark, not markedly swollen. Cauda tongue-, helmet or finger-shaped	…..2
2	Head with well-developed, steep-sided, scabrous ANT tubercles. SIPH pale, tapering from broad base, with very coarse imbrication, 3.5-4.0 × cauda. Subgenital plate strongly produced posteriorly, broadly conical	…..Myzus siegesbeckicola
–	Without that combination of characters	…..3
3	Triommatidium merged with compound eye, so that there is no distinct ocular tubercle. Dorsal hairs fan-shaped. ANT PT/BASE 1.4-2.0. SIPH cylindrical for most of length, slightly swollen subapically. R IV+V with slightly concave sides	…..Coloradoa rufomaculata
–	Triommatidum forming a distinct ocular tubercle at posterior margin of eye, dorsal hairs with blunt or pointed apices, and other characters not in above combination	…..go to key to polyphagous aphids

*Sieglingia* see Danthonia	Poaceae
*Sieglingia decumbens* = Danthonia decumbens

*Silaum* (including Silaus)	Apiaceae
*Silaum alpestre*	Aphis fabae, [franzi]
S. besseri	Aphis silaumi; Cavariella archangelicae
S. pratense = S. silaus
S. silaus	Aphis fabae; Aulacorthum solani; Cavariella aegopodii;
	Myzus ascalonicus

Key to apterae on Silaum:-

1	ABD TERG 8 with a backwardly directed process above the cauda, bearing 2 hairs. SIPH clavate	…..2
–	No supracaudal process	…..3
2	ANT PT/BASE 0.6-1.3. R IV+V 0.7-0.9 × HT II, without any accessory hairs	…..Cavariella aegopodii
–	ANT PT/BASE 1.5-2.0. R IV+V 1.0-1.1 × HT II, with 2 accessory hairs	…..Cavariella archangelicae
3	ABD TERG 1 and 7 with marginal tubercles (MTu). Cauda and SIPH both dark	…..4
–	ABD TERG 1 and 7 without MTu. Cauda and SIPH pale	…..go to key to polyphagous aphids, starting at couplet 5

4	R IV+V 0.9-1.1 × HT II. ANT 6-segmented	……Aphis fabae
–	R IV+V c.1.4-1.5. ANT often seeming 5-segmented due to fusion of III and IV	…..Aphis silaumi*

*Silene* (including Oberna, Otites)	Caryophyllaceae
*Silene acaulis*	Aulacorthum solani; Myzus icelandicus
*S. alba* = S. latifolia ssp. alba
*S. alpina*	Volutaphis alpinae
*S. angustifolia*	Aphis sambuci
S. atropurpurea	Volutaphis centaureae
S. baccifera	Aphis fabae; Brachycaudus lychnicola, lychnidis;
	Macrosiphum euphorbiae; [Nasonovia ribisnigri]
S. behen	Brachycaudus lychnidis, populi; Brachycolus cucubali
S. bellidifolia	Brachycaudus klugkisti, lychnidis
S. borysthenica	Aphidura pannonica, pujoli; Brachycaudus lychnidis
S. brahuica	Aphidura massagetica
*S. bupleuroides*	Aphis fabae, sambuci
*S. chalcedonica*	Myzus persicae
S. chlorantha	Brachycolus cucubali
*S. coeli-rosea*	[Macrosiphum centranthi]; Myzus persicae
S. colorata	Myzus persicae
S. commutata = S. vulgaris ssp. commutata
*S. compacta*	[Brachycaudus sp. (Switzerland: Lampel 1976)]
S. conica	Aphis craccivora; Brachycaudus helichrysi;
	Macrosiphum stellariae
*S. conoidea*	Aphidura picta; Aphis craccivora;
	Myzus certus, persicae; [Rhopalosiphum maidis];
	Sitobion sp. (Dutta & Gautam 1993)
*S. coronaria*	Aphis sambuci; Brachycaudus lychnidis
S. crassipes	Myzus persicae
S. csereii	Bracycaudus populi
S. cucubalus = S.vulgaris
S. dichotoma	Brachycaudus lychnidis
S. dioica	Aphis fabae, sambuci; Aulacorthum solani;
	Brachycaudus klugkisti, lychnicola, lychnidis;
	Myzus ascalonicus, cymablariae, ornatus, persicae;
	[aphid gall: Wahlgren 1956]
*S. dioica* ssp. lapponica = Melandrium lapponicum
*S. dubia* = S. nutans ssp. dubia
S. firma	Aphis silenicola
S. flos-cuculi	Aphis sambuci;
	Brachycaudus klugkisti, lychnicola, lychnidis;
	Myzus ascalonicus;
	Volutaphis centaureae,
	[Volutaphis sp. (Börner 1952: 116)]
S. fruticosa	Aphidura picta
*S. fruticulosa*	Aphidura nomadica
S. gallica	Aphidura gallica; Aulacorthum solani;
	Brachycaudus helichrysi, lychnidis; Myzus persicae
S. glauca = S. secundiflora
S. glaucifolia	[Myzus sp. (Spain: Mier Durante & Nieto Nafría 1978)]
S. inaperta	Aphidura ornata
S. inflata = S.vulgaris
S. italica	Aphidura delmasi, ornata, picta; Aulacorthum solani;
	Brachycaudus lychnidis; Myzus ascalonicus
S. italica ssp. nemoralis	Brachycaudus klugkisti
S. jeniseensis	Aphis silenicola
S. kuschakewiczii	Aphidura ornatella
S. latifolia (= Melandrium album)	Aphidura melandrii;
(incl. ssp. alba)	Aphis austriaca, craccivora, fabae, nasturtii, sambuci;
	Aulacorthum solani;
	Brachycaudus divaricatae, klugkisti, lychnidis, populi;
	Macrosiphum stellariae;
	Myzus ascalonicus, certus, persicae; Volutaphis schusteri
S. latifolia × dioica	Brachycaudus klugkisti; Myzus persicae
S. lithophila	Aphidura massagetica, ornatella; Aphis craccivora
S. littoralis	Brachycaudus populi
S. longiflora = S. bupleuroides
S. macrostyla	Aphis silenicola
S. maritima = S. uniflora
S. media	Aphidura pannonica; Aphis silenicola
S. moldavica	Aphidura pannonica
S. multifida	Aphis gossypii; Brachycaudus divaricatae, lychnidis
S. multiflora	Brachycaudus lychnidis; Volutaphis schusteri
S. nemoralis = S. italica ssp. nemoralis
S. noctiflora	Aphis craccivora, sambuci;
	Brachycaudus klugkisti, lychnidis;
	Macrosiphum euphorbiae; Myzus certus;
	[Uroleucon rudbeckiae]
*S. nutans*	Aphidura delmasi, ornata; Aphis austriaca, sambuci;
	Brachycaudus lychnidis, pallidus, populi;
	Brachycolus cucubali; Myzus certus;
	Volutaphis centaureae
S. nutans ssp. dubia	Brachycaudus lychnidis
*S. otites*	Aphidura ornata, pannonica, picta; Aphis austriaca;
	Volutaphis centaureae
S. paradoxa	Aphidura gallica, picta
S. parviflora = S. borystenica
S. pendula	Volutaphis centaureae
S. repens	Aphis silenephaga, silenicola; Brachycaudus lychnidis;
	Volutaphis centaureae
S. rosea see S. uniflora
S. rubra (?)	Brachycaudus klugkisti
S. salzmannii = S. tyrrhenia
*S. saxifraga*	Aphis ornata; Aphis sambuci
S. scabrifolia (?)	[Uroleucon sileneobium]
S. schafta	Brachycaudus populi
S. secundiflora	Aphidura picta
*S. sendtneri*	Brachycaudus lychnidis
*S. suffrutescens* = S. fruticulosa
*S. swertiaefolia* (?)	Aphidura ornata
*S. thymifolia*	Aphidura picta (as mingens)
*S. tyrrhenia*	Brachycaudus lychnidis
*S. uniflora* (incl. maritima, rosea)	Acyrthosiphon auctum;
	Brachycaudus klugkisti, lychnidis, populi;
	Macrosiphum euphorbiae, penfroense, stellariae;
	Myzus icelandicus, ornatus, persicae
S. viridiflora	Myzus certus, persicae
S. viscaria	Aphis fabae, sambuci; Brachycaudus lychnidis;
	Volutaphis centaureae
S. viscosa	Aphidura delmasi; Aphis austriaca, fabae, sambuci;
	Brachycaudus klugkisti, lychnidis; Myzus certus;
	Volutaphis centaureae
*S. vulgaris* (incl. cucubalis, inflata, wallichiana)	Aphidura ornata, ornatella;
	Aphis austriaca, craccivora, fabae, sambuci;
	Aulacorthum solani;
	Brachycaudus lychnidis, populi;
	Brachycolus cucubali;
	Macrosiphum euphorbiae, hartigi, stellariae;
	Myzus ascalonicus, certus, persicae; [Pemphigus inflatae]
*S. vulgaris* ssp. commutata	Aphidura ornatella; Brachycaudus lychnidis, populi
*S. wallichiana* = S. vulgaris
S. wolgensis	Aphidura ornata, ornatella, pannonica ssp. cretacea
Silene spp.	Aphidura amphorosiphon; [Roepkea marchali];
	Volutaphis karatavica

Key to apterae on Silene (including Melandrium, Oberna):-

1	Cauda semicircular or helmet-shaped, shorter than its width at base in dorsal view. Marginal tubercles (MTu) small or absent, and never on ABD TERG 7. Spiracular apertures large and rounded. Dorsum usually with an extensive dark sclerotic shield	…..2
–	Cauda tongue-shaped, finger-shaped, or if short and rounded then there are large MTu on ABD TERG 7. Spiracular apertures reniform. Dorsum with or without an extensive dark sclerotic shield	…..7
2	R IV+V 0.8-1.0 (-1.09) × HT II	…..Brachycaudus populi
–	R IV+V (1.0-) 1.1-1.6 × HT II	…..3
3	ANT III with 7-15 hairs, the longest 17-29 μm long, 0.5-1.3 × BD III, and 0.29-0.56 × the longest spinal hair on ABD TERG 3-4. Cauda with 6-12 hairs	…..Brachycaudus klugkisti
–	ANT III with 13-24 hairs, the longest 24-69 μm long, 0.9-2.8 × BD III, and 0.63-1.4 × the longest spinal hair on ABD TERG 3-4. Cauda with 11-18 hairs	…..4
4	R IV+V 2.95-8.3 × longest spinal hair on ABD TERG 3-4, which is 17-57 μm long	…..5
–	R IV+V 1.80-2.85 × longest spinal hair on ABD TERG 3-4, which is 54-85 μm long	…..6
5	R IV+V 0.163-0.177 mm long, with 5-10 accessory hairs. ANT III 2.72-3.13 × SIPH	…..Brachycaudus pallidus
–	R IV+V 0.183-0.218 mm long, with 8-14 accessory hairs. ANT III 2.05-2.42 × SIPH	…..Brachycaudus lychnidis

6	Hairs on ANT III with blunt or acute apices, the longest 1.0-1.8 × BD III. R IV+V 1.0-1.42 × HT II	…..Brachycaudus divaricatae
–	Hairs on ANT III with very finely pointed apices, the longest (1.8-) 2.0-3.0 × BD III. R IV+V 1.28-1.74 × HT II	…..Brachycaudus lychnicola
7	Marginal tubercles (MTu) always present on prothorax and ABD TERG 1 and 7, and sometimes on other segments	…..8
–	MTu absent or of irregular occurrence, sometimes present on prothorax and some of ABD TERG 1-5 (-6), but never on ABD TERG 7	…..14
8	ABD TERG 2-4 (-6) as well as 1 and 7 with well-developed MTu	…..9
–	ABD TERG 2-4 only irregularly with small MTu	…..11
9	SIPH 0.55-0.95 × cauda, which is finger-like. MTu placed on dark marginal sclerites. R IV+V 0.95-1.15 × HT II	…..Aphis silenicola
–	SIPH 1.7-3.5 × cauda, which is short and rounded. MTu not placed on dark marginal sclerites. R IV+V 1.1-1.7 × HT II	…..10
10	Cauda with 7-12 hairs. (Al. with sec. rhin. III 17-20, IV c.4, V 0)	…..Aphis austriaca
–	Cauda with 10-20 hairs. (Al. with sec. rhin. III 12-44, IV 10-27, V 3-15	…..Aphis sambuci
11	SIPH 0.4-0.5 × cauda. R IV+V c.0.7 × HT II	…..Aphis silenephaga*
–	SIPH 0.7-2.2 × cauda. R IV+V 0.9-1.2 × HT II	…..12
12	Tergum with an almost solid black shield, occasionally fragmented	…..Aphis craccivora
–	Tergum without extensive dark sclerotisation anterior to SIPH	…..13
13	SIPH pale with dark apices. Longest hairs on ANT III 0.4-0.7 × BD III. Dorsal abdomen without any dark markings	…..Aphis nasturtii
–	SIPH black. Longest hairs on ANT III 0.8-3.4 × BD III. Dorsal abdomen with dark cross-bands on ABD TERG 7-8, and usually some small dark markings anterior to SIPH	……Aphis fabae

14	SIPH very short, barrel-shaped, 0.39-0.53 × cauda	…..Brachycolus cucubali
–	SIPH at least 0.8 × cauda	…..15
15	Head densely spiculose both dorsally and ventrally, with well-developed, steep-sided ANT tubercles	…..16
–	Head smooth, or with a few spicules ventrally. ANT tubercles weakly developed or if well developed then with smooth, divergent inner faces	…..20
16	SIPH slightly to moderately clavate	…..17
–	SIPH tapering/cylindrical	…..19
17	SIPH 0.54-0.81 × ANT III, almost smooth surfaced, with a narrow stem similar in thickness to middle part of hind tibia	…..Myzus ascalonicus
–	SIPH 0.82-1.34 × ANT III, normally imbricated, with narrowest part of stem distinctly thicker than middle part of hind tibia	…..18
18	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)	…..Myzus certus
19	BL 1-2 mm. ANT PT/BASE 1.7-2.8. ANT III without rhinaria. SIPH coarsely imbricated, with a slight “S”-curve. Dorsum with a pattern of intersegmental dark spots	…..Myzus ornatus
–	BL 1.8-3 mm. ANT PT.BASE 4.0-5.5. ANT III with (0-)1-2(-4) rhinaria near base. SIPH normally imbricated, rather straight. Dorsum without dark intersegmental markings	…..Aulacorthum solani

20	SIPH with a subapical zone of polygonal reticulation	…..21
–	SIPH without polygonal reticulation	…..25
21	ANT III with 10-33 rhinaria extending over most of length. R IV+V 0.60-0.84	…..22
–	ANT III with 1-12 rhinaria concentrated near base or on basal half. R IV+V 0.83-1.02	…..23
22	SIPH 1.55-1.94 × cauda. (Al. with 36-43 secondary rhinaria on ANT III)	…..Macrosiphum eastopi
–	SIPH 1.22-1.58 × cauda. (Al. with 18-35 secondary rhinaria on ANT III)	…..Macrosiphum hartigi
23	ANT PT/BASE 3.1-4.8. SIPH 1.4-1.8 × cauda which bears 12-22 hairs	…..Macrosiphum penfroense

–	ANT PT/BASE 4.2-6.4. SIPH 1.7-2.3 × cauda which bears 8-16 hairs	…..24
24	Femora usually with a dark spot or patch near apices. 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

25	SIPH 0.85-1.4 × cauda	…..26
–	SIPH 1.5-2.8 × cauda	…..29
26	SIPH tapering/cylindrical. ANT III with 0-3 rhinaria near base	…..Acyrthosiphon auctum
–	SIPH swollen on apical c.0.7. ANT III with or without rhinaria, if with rhinaria then these are on distal half	……27
27	ANT IV with 7-11 secondary rhinaria	…..Volutaphis karatavica
–	ANT IV without rhinaria	……28
28	ANT PT/BASE 2.5-3.0. SIPH 1.2-1.4 × cauda. R IV+V longer than HT II. First tarsal segments with 3 hairs	…..Volutaphis centaureae
–	ANT PT/BASE 1.8-2.2. SIPH 0.95-1.1 × cauda. R IV+V shorter than HT II. First tarsal segments with 4 hairs	…..Volutaphis alpinae
29	ANT III with 6-26 rhinaria (all or most being on distal half), and IV with 0-9. ANT PT/BASE 4.7-7.4. Mesosternum without mammariform processes. Tergum without dark sclerotisation	…..Volutaphis schusteri
–	ANT III-IV without rhinaria. ANT PT/BASE 2.4-4.5. Anterior part of mesosternum with a pair of mammariform processes. Tergum often with dark sclerotisation	…..30
30	SIPH distinctly swollen on distal half (maximum width of swollen part at least 1.2 × minimum width basad)	…..31
–	SIPH cylindrical, subcylindrical, tapering from base to apex (sometimes outwardly curved), or slightly swollen (maximum width at most 1.2 times minimum width basad)	…..34
31	Tergum with an extensive almost solid black shield extending over metanotum and ABD TERG 1-6, usually incorporating marginal sclerites	…..32
–	Tergum pale or with variable sclerotisation, sometimes extensive but with large windows spinally and marginally, not forming a solid black shield	…..33
32	Hairs on median frontal tubercle 25-32 µm long, 1.1-1.5 × ANT BD III. Mesosternal processes well-developed, steep-sided, almost as high as their basal widths	….. Aphidura ornatella
–	Hairs on median frontal tubercle 40-44 µm long, 1.8-2.0 × ANT BD III. Mesosternal processes low with gently sloping sides, much lower than their basal widths	….. Aphidura melandrii*

33	ANT PT/BASE 2.5-3.1. RIV+V 1.2-1.5 × HT II. Cauda 1.1-1.5 times its basal width, with 6-7 hairs. Abdomen variable sclerotised and pigmented	….. Aphidura amphorosiphon
–	ANT PT/BASE 3.2-4.5. RIV+V 1-1.2 × HT II. Cauda 1.1-1.2 times its basal width, with 7-11 hairs. ABD TERG 1–6 with a dark central patch and marginal sclerites	….. Aphiduranomadica*

34	SIPH pale or dusky, slightly clavate, 1.5-1.8 × cauda, which is short and triangular. Tergum without sclerotisation, completely pale	….. Aphidura pujoli
–	SIPH brown to black at least in part, sometimes slightly clavate, 1.9-2.8 × cauda. Tergum with variable sclerotisation and pigmentation, rarely complete pale	…..35
35	ABD TERG 2-3 with longest hairs 35-55 μm long, 1.5-2.0 × ANT BD III. ANT I long, 1.3-1.5 × its maximal width. Dorsal abdomen with a large central oval sclerite extending over ABD TERG (1-)2-5	…..Aphidura delmasi
–	ABD TERG 2-3 with longest hairs 4-25 μm long, 0.2-1.1 × ANT BD III. ANT I short, at most 1.1 × its maximal width. Dorsal abdomen with variable sclerotisation and pigmentation, but rarely with a central oval sclerite on ABD TERG 2-5	…..36
36	Tergum with an extensive almost solid black shield extending over metanotum and ABD TERG 1-6, usually incorporating marginal sclerites. Cauda dark, c.2 × its basal width and with 10-16 hairs	…..Aphidura ornata
–	Tergum pale or with variable sclerotisation, sometimes extensive but with large windows spinally and marginally, not forming a solid black shield. Cauda variable in shape, proportions and colour	…..37
37	Cauda tongue- or finger-shaped, 1.4-1.8 × its basal width	…..38
–	Cauda triangular, although sometimes with a slight constriction, 1.05-1.4 × its basal width	…..39

38	ANT PT/BASE 4.0–5.7. Hairs on ANT III and ABD TERG 2–3 minute, maximally 4–7 μm long, 0.15–0.3 × BD III. SIPH 2.2–2.8 × cauda	….. Aphidura pannonica
–	ANT PT/BASE 2.5–4.0. Hairs on ANT III and ABD TERG 2–3 maximally 8–22μm, 0.4–1.0 × BD III. SIPH 1.9–2.5 × cauda	….. Aphidura picta
39	RIV+V 0.9-1.0 × HT II, with 8-10 accessory hairs. Hairs on ABD TERG 2-3 are 8-11 μm long, 0.3-0.5 × BD III	….. Aphidura massagetica*
–	RIV+V 1.05-1.45 × HT II, with 10-16 accessory hairs. Hairs on ABD TERG 2-3 are 13-23 μm long, 0.6-1.0 × BD III	…..Aphidura gallica

*Silphium*	Asteraceae
*Silphium compositum*	Uroleucon ambrosiae
*S. integrifolium*	Macrosiphum pallens; Uroleucon rudbeckiae
S. laciniatum	Iowana frisoni
S. perfoliatum	Uroleucon rudbeckiae
S. terebinthinaceum	Iowana frisoni

Key to apterae on Silphium:-

1	ANT tubercles undeveloped, front of head broad and flat in dorsal view. ANT 5-segmented, with 0-21 rhinaria on distal half of ANT III. Large marginal tubercles (MTu) present on prothorax and ABD TERG 1-5 and 7. SIPH short, tapering, flangeless, without distal reticulation. Cauda broadly rounded, shorter than its basal width	…..Iowana frisoni*
–	ANT tubercles well developed, ANT 6-segmented. MTu absent or only ever on ABD TERG 2-4. SIPH with a distal zone of polygonal reticulation, and cauda finger-shaped	…..2
2	SIPH long, thin, pale, with a few rows of large polygonal cells on less than distal 0.2 of length. ANT III with longest hairs less than 0.5 × BD III, and with 2-4 rhinaria	…..Macrosiphum pallens

–	SIPH thick, mainly or entirely dark, with numerous rows of small polygonal cells on distal 0.25-0.4 of length. ANT III with longest hairs as long as or longer than BD III, and with 8-31 rhinaria	…..3
3	Femora pale/dusky, sometimes with darker patch on anterior side at apices. SIPH becoming gradually darker distally, paler at base than at apex. Postsiphuncular sclerites and scleroites at bases of dorsal hairs pale and inconspicuous	…..Uroleucon rudbeckiae
–	Femora dark distally. SIPH entirely dark. Postsiphuncular sclerites and at least some of scleroites at base of dorsal hairs pigmented	…..Uroleucon ambrosiae

*Silybum*	Asteraceae
*Silybum marianum*	Aphis fabae, solanella, spiraecola;
	Aulacorthum solani; Brachycaudus cardui, helichrysi;
	Capitophorus elaeagni, horni;
	Dysaphis lappae ssp. cynarae; Macrosiphum euphorbiae;
	Protaphis terricola; Protrama radicis;
	[Rectinasus buxtoni]; Trama troglodytes;
	Uroleucon aeneum

Use key to apterae on Cynara.

*Simmondsia*	Simmondsiaceae
*Simmondsia chinensis*	Aphis craccivora, fabae; Macrosiphum euphorbiae;
	Myzus persicae

Use key to polyphagous aphids.

*Simsia*	Asteraceae
Simsia amplexicaulis	Hyperomyzus pullatus; Uroleucon ambrosiae

Couplet for separating these two species:-

–	SIPH tapering/cylindrical, black, with distal zone of polygonal reticulation	…..Uroleucon ambrosiae
–	SIPH swollen in middle, pale to dusky, without polygonal reticulation	…..Hyperomyzus pullatus

*Sinapidendron*	Brassicaceae
*Sinapidendron rupestre*	Brevicoryne brassicae

*Sinapis*	Brassicaceae
*Sinapis alba*	Aphis craccivora, gossypii; Aulacorthum solani;
	Brevicoryne brassicae;
	Lipaphis erysimi, pseudobrassicae;
	Macrosiphum euphorbiae; Myzus persicae;
	Neomyzus circumflexus; Smynthurodes betae
*S. arvensis*	Acyrthosiphon gossypii; Aphis nasturtii, triglochinis;
	Brachunguis harmalae; Brevicoryne brassicae;
	Lipaphis erysimi, pseudobrassicae;
	Macrosiphum euphorbiae; Myzus [cerasi], persicae;
	Nasonovia ribisnigri; Smynthurodes betae
S. flexuosa	Brevicoryne brassicae; Lipaphis erysimi;
	Smynthurodes betae

See key to apterae on Brassica and Sinapis under Brassica

*Sinarundinaria*	Poaceae
Sinarundinaria niitakayamensis = Yushania niitakayamensis
S. reticulata = Phyllostachys bambusoides

*Sindora*	Fabaceae
*Sindora* sp.	Anomalosiphum murphyi

*Sinningia* (including Corytholoma, Rechsteineria)	Gesneriaceae
*S. eumorpha × leucotrichia*	Aulacorthum solani
S. ×hybrida	Myzus ornatus
S. speciosa	Aulacorthum solani; Myzus persicae;
	Neomyzus circumflexus
*S. verticillata*	Aulacorthum solani
Sinningia × Gloxinia	Aulacorthum solani (Leonard 1972a)

Use key to polyphagous aphids.

*Sinojackia*	Styracaceae
*Sinojackia xylocarpa*	Aleurodaphis sinojackiae

*Siphocampylus*	Campanulaceae
*Siphocampylus cernuus*	Aphis spiraecola

*Sison*	Apiaceae
*Sison amomum*	Aphis fabae

*Sisymbrium*	Brassicaceae
*Sisymbrium alliaria* = Alliaria petiolata
S. altissimum	Brevicoryne brassicae; Lipaphis erysimi, pseudobrassicae;
	Myzus persicae; [Protaphis middletonii]
S. arnottianum = Polypsecadium arnottianum
S. aromaticum (?)	Lipaphis erysimi
S. austriacum	Brevicoryne brassicae; Myzus persicae
S. bermudiana (?)	[Dysaphis foeniculus]
S. canescens = Descurainia pinnata
S. capense	Myzus persicae
S. incisum = Descurainia incisa
S. irio	Aphis gossypii; Brevicoryne brassicae;
	Lipaphis erysimi, fritzmuelleri;
	Macrosiphum euphorbiae; Myzus persicae;
	[Sitobion rosaeiformis]
S. loeselii	Brevicoryne brassicae;
	Lipaphis erysimi, fritzmuelleri, sisymbrii;
	Myzus persicae; Neosappaphis paradoxa;
	Smynthurodes betae
S. officinale	Aphis craccivora, fabae, nasturtii; Aulacorthum solani;
	Brevicoryne brassicae; [Cavariella aegopodii];
	Lipaphis erysimi, lepidii; Macrosiphum euphorbiae;
	Myzus ascalonicus, persicae; Nasonovia ribisnigri;
	[Sitobion fragariae]; [Uroleucon cichorii]
*S. orientale*	Brevicoryne brassicae; Lipaphis erysimi; Myzus persicae
S. polymorphum	Brevicoryne brassicae; Lipaphis erysimi, sisymbrii;
	Neosappaphis paradoxa; Smynthurodes betae
S. sofia = Descurainia sophia
*S. strictissimum*	Myzus persicae
*S. thellungii* = Erucastrum austroafricanum
Sisymbrium spp.	Acyrthosiphon malvae

Key to apterae on Sisymbrium:-

1	ANT 4-segmented (in al. as well as apt.). ANT III with c.7-9 contiguous sec. rhinaria on distal 0.7. Rather large, flat marginal tubercles (MTu) present on ABD TERG 1-7. SIPH cylindrical, flangeless, pale with dark tips, c.3.5 × cauda which is helmet-shaped and bears c.20 hairs	…..Neosappaphis paradoxa*
–	ANT 5- or 6-segmented, and other characters not as above	…..2
2	SIPH slightly swollen on distal half, with a constriction just proximal to the flange. ANT tubercles absent, or if developed then not projecting forward beyond middle part of head, so that front of head is convex, straight or sinuate in dorsal view. ABD TERG 1 and 7 without marginal tubercles (MTu)	…..3
–	Without this combination of characters; i.e. if SIPH are present then they are tapering, cylindrical or clavate (with narrow section on basal half), and either ANT tubercles are very well-developed or ABD TERG 1 and 7 have MTu	..…8
3	SIPH 0.8-1.05 × cauda, and more-or-less barrel-shaped	…..4
–	SIPH 1.1-c.1.7 × cauda	…..5
4	Cauda broad-based, triangular, about as long as basal width, with 7-8 hairs. Dorsal abdomen usually with paired dark markings on most tergites	…..Brevicoryne brassicae
–	Cauda tongue-shaped, longer than its basal width, with 4 hairs. Dorsal abdomen without dark markings anterior to SIPH	…..Lipaphis fritzmuelleri
5	ANT tubercles undeveloped, front of head convex in dorsal view. ANT less than 0.5 × BL. ABD TERG 8 with a rugose medial swelling (Fig.37b)	.….Lipaphis lepidii
–	ANT tubercles developed, projecting about as far as median tubercle, so that front of head is sinuate in outline in dorsal view. ANT more than 0.5 × BL. ABD TERG 8 without a rugose swelling	.….6
6	SIPH c.1.7 × cauda, which is c. 2.5 × R IV+V	…..Lipaphis sisymbrii*
–	SIPH 1.1-1.6 × cauda, which is 1.2-2.0 × R IV+V	…..7
7	ANT III + PT together 1.95-2.5 × SIPH (90% of specimens less than 2.4 ×)	…..Lipaphis erysimi
–	ANT III + PT together 2.1-3.2 × SIPH (90% of specimens more than 2.4 ×)	…..Lipaphis pseudobrassicae

8	Thoracic spiracles enlarged, much larger than abdominal spiracles. ANT PT/BASE 7.0-11.4, usually more than 8.0. Hairs on ANT III 0.7-1.1 × BD III. Dorsum usually with paired dark intersegmental markings	…..Nasonovia ribisnigri
–	Without that combination of characters	..…go to key to polyphagous aphids

*Sisyrinchium*	Iridaceae
*Sisyrinchium graminifolium*	Metopolophium dirhodum; Rhopalosiphum padi;
	Schizaphis graminum
*S. idahoense*	Macrosiphum euphorbiae
Sisyrinchium sp.	Dysaphis tulipae; Sitobion avenae

Use key to apterae on Iris.

*Sitanion*	Poaceae
*Sitanion hystrix*	Sitobion fragariae

(or use key to apterae of grass-feeding aphids under Digitaria)

*Sium*	Apiaceae
Sium cicutifolium = S. suave
S. latifolium	Aphis fabae; Cavariella aegopodii, angelicae, cicutae,
	konoi, salicicola;
	Dysaphis foeniculus; Macrosiphum euphorbiae;
	Pemphigus protospirae
S. medium	Dysaphis foeniculus
S. nipponicum = S. suave
S. reflexum (?)	Aphis asclepiadis, fabae; Cavariella aegopodii, salicicola;
	Hyadaphis foeniculi; Paramyzus sii
S. sisaroideum = S. sisarum
S. sisarum	Aphis fabae, solanella; Cavariella cicutae
S. suave (incl. nipponicum)	Aphis gossypii, nasturtii, [sedi]; Aulacorthum solani;
	Cavariella angelicae, [hendersoni], konoi, salicicola;
	Paramyzus sii
*S. tenue*	Cavariella salicicola
Sium sp.	Cavariella salicis

Key to apterae on Sium:-

1	ANT PT/BASE less than 0.5. SIPH absent	.….Pemphigus protospirae
–	ANT PT/BASE more than 0.6. SIPH present	…..2
2	ABD TERG 8 with a posteriorly projecting process above cauda, bearing 2 apical hairs. Tergum variolate	…..3
–	No supracaudal process. Tergum smooth or wrinkled	…..7
3	SIPH tapering/cylindrical, without any swelling. ANT 5-segmented	…..Cavariella angelicae

–	SIPH clavate; swollen on distal half to at least 1.2 × narrowest part of basal half	…..4
4	Supracaudal process conical or finger-like, not projecting to tip of cauda	…..5
–	Supracaudal process large, conical, extending beyond and usually covering cauda	…..6
5	ANT PT/BASE 0.6-1.3. R IV+V 0.7-0.95 × HT II, and without accessory hairs	.….Cavariella aegopodii
–	ANT PT/BASE 1.35-2.0. R IV+V 1.0-1.2 × HT II, with 2 accessory hairs	…..Cavariella konoi
6	R IV+V 1.05-1.2 × HT II. SIPH short and stout, narrowing only at base	…..Cavariella salicicola
–	R IV+V 0.85-1.04 × HT II. SIPH with narrower basal stem extending over about 0.3 of length	…..Cavariella salicis
7	SIPH pale, coarsely imbricated, markedly clavate, with maximum width of swollen part 1.7-2.2 × more than minimum width of stem, with constricted subapical region and very well-developed (swollen) flange. Head densely nodulose and spiculose, with ANT tubercles well developed, the inner faces slightly convergent. ANT III with 1-3 rhinaria in a row near base	…..Paramyzus sii

–	Without that combination of characters	…..8
8	Cauda helmet-shaped, not longer than its basal width. ABD TERG 6-8 all with dark cross-bands. Head and ABD TERG 8 often with spinal tubercles (STu)	……Dysaphis foeniculus
–	Cauda tongue- or finger-like, longer than its basal width, and other characters not as above	…..9

9	SIPH clavate and 0.9-1.4 × cauda	……Hyadaphis foeniculi
–	SIPH tapering or cylindrical (or if clavate then more than 1.5 × cauda)	…..go to key to polyphagous aphids

*Skimmia*	Rutaceae
*Skimmia* sp.	Macrosiphum euphorbiae

*Sloanea*	Elaeocarpaceae
*Sloanea dasycarpa*	Greenidea sp.

Smilacina see Maianthemum

Asparagaceae

*Smilax*	Smilacaceae
Smilax aspera	Aphis gossypii
S. australis	[Sitobion sp. (Australia; Hales et al. 2010)]
S. bracteata	Sitobion smilacicola
S. campestris	Myzus persicae
S. china	Aleurosiphon smilacifoliae; Aphis gossypii, smilacisina;
	Impatientinum impatiens; Macrosiphum euphorbiae;
	[Rhopalomyzus smilacis];
	Sitobion dismilaceti, smilacicola, smilacifoliae
S. domingensis	Aphis (Toxoptera) aurantii
S. elegans	Impatientinum asiaticum ssp. dalhousiensis;
	Sitobion miscanthi
S. excelsa	Aphis fabae
*S. ferox*	Sitobion sikkimense, smilacifoliae
S. glabra	Sitobion smilacifoliae
S. glauca	[Neoprociphilus aceris]
S. glycophylla	[Sitobion sp. (Australia; Hales et al. 2010)]
*S. herbacea*	Neoprociphilus aceris
S. hispida = S. tamnoides
*S. lasioneura*	Neoprociphilus aceris
S. macrophylla Roxb. = S. ovalifolia
S. nipponica	Aulacorthum smilacis
S. oldhami = S. sieboldii
S. ovalifolia	Impatientinum smilaceti
S. parvifolia = S. elegans
S. riparia	Impatientinum impatiens
S. rotundifolia	Neoprociphilus aceris
S. sieboldii	Aulacorthum smilacis; Sitobion smilacifoliae
S. stellata = Maianthemum stellatum
S. stenopetala = S. bracteata
S. tamnoides	Neoprociphilus aceris
Smilax spp.	Aphis spiraecola; [Myzus cerasi], ornatus;
	Neomyzus circumflexus; Pseudomegoura magnoliae;
	[Rhopalosiphoninus smilacifoliae];
	Sinomegoura citricola, [rhododendri]

Key to apterae on Smilax:-

1	ANT PT/BASE less than 0.2. Eyes 3-faceted (triommatidia). Large dorsal wax gland plates present on thorax and abdomen. SIPH as slightly raised pores. Cauda very broadly rounded	…..Neoprociphilus aceris
–	ANT PT/BASE more than 1.5. Eyes multifaceted. No discrete wax gland plates. SIPH tubular. Cauda tongue- or finger-like	…..2
2	ANT tubercles weakly developed. ABD TERG 1 and 7 always with marginal tubercles (MTu). SIPH without a subapical zone of polygonal reticulation	…..3
–	ANT tubercles well developed, so that there is a frontal sinus. ABD TERG 1 rarely and ABD TERG 7 never with MTu. SIPH with or without subapical polygonal reticulation	…..8
3	ANT PT/BASE 3.8-5.0. Stridulatory apparatus present	….. Aphis (Toxoptera) aurantii
–	ANT PT/BASE 1.9-3.5. No stridulatory apparatus	…..4
4	R IV+V with 4-9 accessory hairs. ANT III with long fine hairs, 2-3 × longer than BD III. ABD TERG 1-6 each with a pair of (long, fine) pleural hairs in addition to the spinal and marginal pairs	…..Aleurosiphon smilacifoliae
–	R IV+V with 2 accessory hairs. ANT III with longest hairs 0.4-2.2 × BD III. ABD TERG 1-6 without pleural hairs	…..5
5	Cauda pale, dusky or dark, and bearing 4-8 hairs. Longest hair on hind femur 12-35μm	…..6

–	Cauda black and bearing 7-24 hairs. Longest hair on hind femur 24-90 μm	…..7
6	Cauda 0.9-1.2 × SIPH, with 6-8 hairs	…..Aphis smilacisina
–	Cauda 1.3-2.5 × SIPH, with 4-8 hairs	…..Aphis gossypii
7	Dorsal abdomen with dark cross-bands on ABD TERG 7 and 8, and usually with some small dark sclerites anterior to SIPH. Cauda without a constriction, and bearing 11-24 hairs	…..Aphis fabae

–	Dorsal abdomen without dark dorsal markings, except rarely a narrow cross-band on ABD TERG 8. Cauda usually with a constriction, and bearing 7-15 hairs	…..Aphis spiraecola
8	Head spiculose, at least on ventral side	…..9
–	Head not spiculose	…..13
9	Dorsal abdomen without any dark markings. SIPH slightly clavate	…..10
–	Dorsal abdomen with often extensive dusky or dark sclerotic markings. SIPH tapering/ cylindrical	…..11
10	ANT III without rhinaria. Femora pale. Head pale and densely spiculose dorsally as well as ventrally, with apically convergent scabrous ANT tubercles	…..Myzus persicae
–	ANT III with a small rhinarium near base. Femora dark distally. Head dark and spiculose only on ventral side, with inner faces of ANT tubercles almost parallel	…..Pseudomegoura magnoliae

11	Dorsal abdomen with sclerotisation confined to a pattern of dark intersegmental flecks. ANT PT/BASE 1.7-2.8	…..Myzus ornatus
–	Dorsal abdomen with more extensive sclerotisation. ANT PT/BASE more than 3	…..12
12	Dorsal abdomen with a U-shaped black sclerite centred on ABD TERG 2-4, not extending to marginal areas. Femora pale distally	…..Neomyzus circumflexus
–	Dorsal abdomen with variably-developed dusky or dark sclerotisation, extending into marginal areas when well developed. Femora dark distally	…..Aulacorthum smilacis
13	SIPH pale on about basal 0.3, and 0.8-1.1 × cauda, which is black	…..Sinomegoura citricola

–	SIPH wholly dark, at least 1.2 × cauda, which is pale	…..14
14	SIPH 0.15-0.19 × BL, calf-shaped, usually somewhat constricted at base, without subapical reticulation or with a few rows of strongly transverse cells on distal 0.15 or less	…..15
–	SIPH 0.20-0.40 × BL, tapering from a broad base, with reticulation on distal 0.2-0.3 of its length	…..17
15	Dorsal abdomen with marginal areas of ABD TERG 1-6 dark, but with a pale central area. First tarsal segments with 4 hairs	…..Impatientinum smilaceti*
–	Dorsal abdomen with a solid black sclerotic shield covering ABD TERG 1-6. First tarsal segments with 3 hairs	…..16
16	Basal part of SIPH and ABD TERG 6 quite smooth. Spiracular sclerites on ABD TERG 1 and 2 small and distinctly separated	…..Impatientinum impatiens
–	Basal part of SIPH and ABD TERG 6 spiculose. Spiracular sclerites on ABD TERG 1 and 2 very close, almost contiguous	…..Impatientinum asiaticum ssp. dalhousiensis
17	SIPH 0.20-0.28 × BL	…..Sitobion sikkimense* (or dismilaceti*?)
–	SIPH 0.3-0.4 × BL	…..18
18	Dorsal abdomen with dusky or dark sclerotisation, varying from dusky fragmented sclerites to a complete dorsal shield. SIPH 1.4-1.9 × cauda, which is distally thin and tapering, nearly 3 × longer than its basal width, and bears 6-8 hairs. Femora and tibiae without glandular pores	…..Sitobion smilacifoliae
–	Dorsal abdomen without dusky/dark markings. SIPH c.2.7 × cauda, which is stout, about 2 × its basal width and bears c.16 hairs. Femora and tibiae with numerous small glandular(?) pores	…..Sitobion smilacicola*

*Smithia*	Fabaceae
*Smithia sensitiva*	Aphis craccivora

*Smodingium*	Anacardiaceae
*Smodingium argutum*	Aphis odinae

*Smyrnium*	Apiaceae
*Smyrnium olusatrum*	Aphis fabae; Aulacorthum solani; Cavariella aegopodii;
	Dysaphis apiifolia, crataegi, lauberti;
	Hyadaphis foeniculi; Myzus ornatus, persicae;
	Semiaphis dauci
S. orphanidis	Dysaphis apiifolia
S. perfoliatum	Aphis fabae
S. rotundifolium	[Brachycaudus helichrysi]; Dysaphis crataegi

Use key to apterae on Conium.

*Sobralia*	Orchidaceae
*Sobralia leucoxantha*	Aphis (Toxoptera) aurantii
Sobralia sp.	Cerataphis orchidearum

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

*Solandra*	Solanaceae
*Solandra grandiflora*	Myzus persicae

*Solanecio*	Asteraceae
*Solanecio biafrae*	Aphis gossypii
*S. mannii*	Aphis fabae, gossypii, spiraecola;
	Brachycaudus helichrysi; Macrosiphum euphorbiae;
	Myzus ornatus; Uroleucon compositae

Use key to polyphagous aphids (or try key to apterae on Senecio).

*Solanum*	Solanaceae
*Solanum acanthoideum*	Aphis gossypii
S. aculeatissimum = S. capsicoides
S. aethiopicum	Aphis gossypii; Myzus persicae
S. americanum	Aphis fabae, solanella; Macrosiphum euphorbiae;
	Myzus persicae; Neomyzus circumflexus
S. anguivi	Aphis gossypii
S. antillarum = S. aphyodendron
*S. aphyodendron*	Aphis aurantii, gossypii, spiraecola
S. aurantiacum	Myzus ornatus
S. auriculatum = S. mauritianum
S. aviculare	Myzus persicae
S. bahamense	Aphis gossypii
S. berthaultii	Macrosiphum euphorbiae
S. betaceum	Aphis fabae, nerii
S. brachyantherum	Brachycaudus helichrysi
S. campechiense	Macrosiphum euphorbiae; Myzus persicae
S. capsicastrum = S. pseudocapsicum
S. capsicoides	Aphis gossypii; Neomyzus circumflexus;
	Rhopalosiphum rufiabdominale
S. caribaeum = S. americanum
S. carolinense	Macrosiphum euphorbiae; Myzus persicae
S. catombelense	Myzus persicae
S. chacoense	Aphis gossypii
S. chenopodioides	Aphis fabae; Myzus persicae
S. ciliatum = S. capsicoides
S. clavatum = Cyphomandra clavata
S. depilatum = S. americanum
S. dilleni	Aphis fabae
S. donianum	Aphis gossypii; Aulacorthum solani;
	Brachycaudus helichrysi; Myzus persicae
S. douglasii = S. nigrescens
S. dulcamara	[Acyrthosiphon pisum];
	Aphis craccivora, fabae, gossypii, solanella,
	[solani Kittel (invalid name)];
	Aulacorthum solani; Macrosiphum euphorbiae;
	Myzus persicae
S. eardleyae (?)	Aphis gossypii
S. elaeagnifolium	Aphis gossypii; Myzus persicae
S. eremophilum (?)	Macrosiphum euphorbiae; Myzus persicae
S. esculentum = S. melongena
S. flagellare	Macrosiphum euphorbiae; Myzus persicae
S. giganteum	Aphis fabae, [scabiosae of Theobald (1927) and Wilson (1918)];
	Aulacorthum solani; Myzus persicae
S. gilo = S. aethiopicum
*S. guanicense* = S. campechiense
S. guianense = Lycianthes pauciflora
*S. hendersonii*	Macrosiphum euphorbiae
*S. hirsutum*	Aphis gossypii
S. incanum	Macrosiphum euphorbiae
S. indicum	Aphis gossypii; Myzus persicae
S. integrifolium = S. aethiopicum
S. intrusum	Aphis solanella
S. jasminoides = S. laxum
S. khasianum = S. capsicoides
S. laciniatum	Aphis gossypii; Myzus persicae; Smynthurodes betae
S. laxum	Aphis fabae, gossypii; Aulacorthum solani;
	Macrosiphum euphorbiae; Myzus persicae;
	Neomyzus circumflexus
S. luteum	Aphis fabae, frangulae, gossypii, solanella;
	Aulacorthum solani; Myzus persicae
S. lycopersicon = Lycopersicon esculentum
S. lyratum	Neomyzus circumflexus
S. macranthum	Aphis gossypii
S. marginatum	Aphis fabae (?solanella); Macrosiphum euphorbiae;
	Myzus persicae
S. mauritianum	Aphis gossypii, spiraecola
S. melongena	Aphis citricidus, craccivora, fabae, gossypii, nasturtii,
	nerii, spiraecola;
	Aulacorthum solani; Brachycaudus helichrysi;
	Macrosiphum euphorbiae;
	Myzus antirrhinii, ornatus, persicae;
	Neomyzus circumflexus; [Pentalonia nigronervosa];
	Pseudomegoura magnoliae;
	Rhopalosiphoninus latysiphon;
	Rhopalosiphum padi, rufiabdominale;
	Smynthurodes betae
S. montanum	Aphis gossypii; Macrosiphum euphorbiae;
	Myzus persicae
S. muricatum	Macrosiphum euphorbiae; Myzus persicae
S. nigrescens	Smynthurodes betae
S. nigrum (incl. schultesii)	Aphis craccivora, [euonymi], fabae, gossypii, nasturtii,
	[neoreticulata of Ossiannilsson1964a (fabae group)],
	nerii, [rumicis], solanella, [solani Kittel (invalid name)],
	spiraecola, [umbrella];
	Aulacorthum solani; Macrosiphum euphorbiae;
	Myzus ornatus, persicae; Neomyzus circumflexus;
	Protaphis middletonii; Rhopalosiphoninus latysiphon;
	Smynthurodes betae
S. nodiflorum = S. americanum
S. panduriforme	Aphis gossypii; Macrosiphum euphorbiae;
	Myzus persicae
S. persicum	Aphis fabae; Myzus persicae
S. pinnatifidum (?)	Brachycaudus helichrysi
S. pseudocapsicum	Aulacorthum solani; Macrosiphum euphorbiae;
	[Metopolophium dirhodum]; Myzus persicae;
	Neomyzus circumflexus
S. quineense	Aphis fabae, solanella
S. quitoense	Aphis gossypii
S. racemiflorum	Aphis gossypii
S. rantonnetii = Lycianthes rantonnei
S. rostratum	Aphis spiraecola; [Rhopalosiphum maidis]
*S. rudepannum* see S. torvum
*S. sarrachoides*	[Brevicoryne brassicae]
*S. saeforthianum*	Aphis fabae, gossypii;
	Myzus persicae, [Myzus sp. (imm.)]
*S. sepicula*	Aphis gossypii
S. sisymbriifolium	Aphis gossypii, solanella, spiraecola; Myzus persicae
S. sodomeum = S. anguivi
S. stramoniifolium	Aphis gossypii
S. sublobatum = S. chenopodioides
S. texanum	Aphis gossypii, solanella
S. torvum (= S. rudepannum)	Aphis aurantii, fabae, gossypii, solanella, spiraecola;
	Aulacorthum [dasi], solani; Brachycaudus helichrysi;
	[Dysaphis emicis]; Myzus persicae;
	[Uroleucon reynoldense]
S. tuberosum	Acyrthosiphon malvae;
	Aphis craccivora, fabae, frangulae, frangulae ssp.
	beccabungae, gossypii, nasturtii, solanella, spiraecola;
	Aulacorthum solani; Brachycaudus helichrysi;
	[Jacksonia papillata]; Macrosiphum euphorbiae;
	Myzus antirrhinii, ascalonicus, ornatus, persicae;
	Neomyzus circumflexus; Pemphigus sp.;
	Pseudomegoura magnoliae;
	Rhopalosiphoninus latysiphon;
	Rhopalosiphum rufiabdominale; Smynthurodes betae;
	[Tuberocephalus misakurae]; Uroleucon compositae
S. variabile	Macrosiphum euphorbiae; Myzus persicae
S. verbascifolium = S. donianum
S. villosum	Aphis solanella, [solani Kittel (invalid name)]
*S. wendlandii*	Aphis fabae, frangulae, gossypii; Myzus persicae
S. xanthocarpum	Aphis gossypii; Myzus persicae
Solanum spp.	[Hyperomyzus lactucae]; Myzus cymbalariae

Use key to polyphagous aphids.

*Solena*	Cucurbitaceae
*Solena amplexicaulis*	Aphis gossypii

*Solenanthus*	Boraginaceae
*Solenanthus biebersteinii*	Brachycaudus mordvilkoi
S. hirsutus	Brachycaudus bicolor

Use key to apterae on Echium.

*Solenostemon* see Plectranthus	Lamiaceae
*Solenostemon monostachyus* = Plectranthus monostachyus
*S. scutellarioides* = Plectranthus scutellarioides

*Solidago*	Asteraceae
*Solidago altissima*	[Aphis gibbosa Rafinesque (invalid name)];
	Macrosiphum euphorbiae;
	Uroleucon [ambrosiae], caligatum, luteolum,
	nigrotuberculatum, pieloui
*S. arguta* (incl. var. bootii)	Uroleucon gravicorne, nigrotuberculatum
*S. aspera* = S. rugosa ssp. aspera
*S. bicolor*	Cachryphora serotinae; Uroleucon nigrotuberculatum
S. bonariensis	Illinoia goldamaryae
S. boottii = S. arguta var. bootii
S. caesia	Aphis coreopsidis, fabae; Pemphigus bursarius;
	Uroleucon caligatum, luteolum
S. canadensis	Acuticauda solidaginifoliae; Aphis solanella, spiraecola;
	Brachycaudus helichrysi; Cachryphora canadensis;
	Illinoia goldamaryae; Pemphigus bursarius;
	Prociphilus erigeronensis; Protaphis middletonii;
	Smynthurodes betae;
	Uroleucon caligatum, erigeronense, gravicorne,
	nigrotuberculatum, pieloui, solidaginis, vancouverense
*S. decurrens*	Aphis fabae, solidagophila;
	Uroleucon lactucicola, solidaginis
*S. elongata*	Uroleucon [ambrosiae], nigrotuberculatum
S. erecta	Pemphigus bursarius
S. fistulosa	Uroleucon sp. (as rudbeckiae)
*S. flexicaulis*	Uroleucon solirostratum
S. gigantea	Uroleucon caligatum, gigantiphagum, luteolum,
	nigrotuberculatum, pieloui, [rudbeckiae]
S. graminifolia = Euthamia graminifolia
S. hispida	Uroleucon gravicorne (? – as canadense)
S. juncea	Uroleucon caligatum, gigantiphagum, gravicorne,
	luteolum, nigrotuberculatum
S. kurilensis	Uroleucon lactucicola
S. lanceolata = Euthamia graminifolia
*S. macrophylla*	Uroleucon sijpkensi
S. microglossa	Uroleucon nigrotibium (? – Brazil)
S. missouriensis	Brachycaudus helichrysi; Myzus ascalonicus;
	Neomyzus circumflexus;
	Uroleucon atripes, luteolum, vancouverense
*S. nemoralis*	[Aphis jacobea-balsamita Rafinesque (invalid name)];
	Uroleucon cadens, gravicorne, luteolum, nigrotibium,
	nigrotuberculatum
S. occidentalis = Euthamia occidentalis
S. odora	[Aphis gibbosa Rafinesque (invalid name)];
	Cachryphora serotinae;
	Uroleucon caligatum, luteolum, nigrotibium,
	nigrotuberculatum
S. patula	Uroleucon pieloui
S. rigida	Brachycaudus helichrysi; Cachryphora serotinae;
	Illinoia goldamaryae; [Uroleucon sp. (as rudbeckiae)]
*S. rugosa*	Cachryphora serotinae; Macrosiphum euphorbiae;
	Uroleucon [ambrosiae], caligatum, lanceolatum, luteolum,
	pieloui, nigrotuberculatum
S. sempervirens	Aphis gossypii, spiraecola;
	Uroleucon [ambrosiae], erigeronense, luteolum,
	nigrotuberculatum, zayasi
S. serotina	Aphis fabae, middeltonii, tsujii;
	Cachryphora canadensis, serotinae;
	[Uroleucon sp. (as rudbeckiae)],
	[U. (Uromelan) sp. (as solidaginis)]
*S. speciosa*	Uroleucon [ambrosiae], gravicorne
*S. spiraeifolia*	Uroleucon lactucicola
S. uliginosa	[Uroleucon pseudambrosiae]
S. ulmifolia	Uroleucon luteolum, nigrotuberculatum
S. virgaurea	Aphis fabae, gossypii, solidaginis;
	Brachycaudus cardui, helichrysi;
	Macrosiphum euphorbiae; Myzus ascalonicus;
	[Nasonovia ribisnigri]; [Pemphigus trehernei];
	Uroleucon amamianum, [kashmiricum], lactucicola,
	[simile], solidaginis
S. virgaurea var. asiatica	Aphis tsujii; Uroleucon amamianum, lactucicola
S. virgaurea var. gigantea	Uroleucon amamianum, lactucicola
S. virgaurea var. lapponica	Uroleucon solidaginis
Solidago spp.	Acuticauda asterensis; Aphis craccivora;
	Aulacorthum solani; Cachryphora imbricaria;
	Hyperomyzus inflatus;
	Uroleucon arnesense, astronomus, bereticum, boreale,
	brevitarsus, [chrysopsidicola]

Key to apterae on Solidago:-

1	ANT PT/BASE less than 1. Eyes with 3 facets. SIPH absent. Dorsal wax glands present	…..2
–	ANT PT/BASE more than 1. Eyes multifaceted. SIPH present, tubular. No discrete wax glands	…..3
2	R IV+V shorter than last antennal segment (BASE + PT), and without any accessory hairs. Hairs at apices of tibiae and first tarsal segments short and thick. Abdomen without posterior projection	…..Pemphigus sp(p).
–	R IV+V longer than last antennal segment (BASE + PT), and bearing 4-8 accessory hairs. Hairs at apices of tibiae and first tarsal segments long and fine. Anus borne on posterior projection of the abdomen	….. Prociphilus erigeronensis
3	SIPH with distal reticulation (at least 2-3 rows of closed polygonal cells)	…..4
–	SIPH without polygonal reticulation (sometimes with subapical transverse striae)	…..29
4	SIPH pale or only dusky towards apices, with polygonal reticulation on subapical 0.04-0.2 of total length. ANT III with 1-10 rhinaria	…..5
–	SIPH dark at least on distal part (although overcleared specimens may be wholly pale), with polygonal reticulation on distal 0.2-0.5 of length. ANT III with 4-47 rhinaria	…..6
5	SIPH slightly swollen on distal half, with reticulated subapical zone only 0.04-0.08 of total length (Fig.49a). Hairs on ANT III and dorsal body less than 0.2-0.4 × BD III. Cauda with 7 hairs	…..Illinoia goldamaryae
–	SIPH cylindrical on distal half, with reticulated subapical zone 0.13-0.2 of total length. Hairs on ANT III and body 0.6-1.1 × BD III. Cauda with 8-12 hairs	…..Macrosiphum euphorbiae
6	SIPH with at least a pale section at base	…..7
–	SIPH entirely dark	…..14
7	SIPH 1.8-2.3 × cauda, which usually has 1-3 subapical hairs that are shorter than those more basad and have blunt or sharply curved apices	…..Uroleucon erigeronense
–	SIPH 1.1-1.7 × cauda, which has subapical hairs similar in length to those more basad, and usually with pointed apices	…..8
8	R IV+V 0.8-1.0 (-1.05) × HT II. SIPH with reticulation only on distal 0.2-0.25 of length	…..Uroleucon bereticum
–	R IV+V 1.1-1.5 × HT II. SIPH with reticulation on distal 0.25-0.5 of length	…..9
9	SIPH longer than ANT III, pale on basal 0.5 or more of length, and with reticulation on distal 0.25-0.33	…..Uroleucon zayasi
–	SIPH not longer than ANT III, and pale only on basal 0.3 or less, with reticulation extending over 0.33-0.5	…..10
10	Second tarsal segments usually without ventral hairs on proximal 0.6 (hair bases may be present, but hairs undeveloped). Cauda with 6-12 hairs	…..11
–	Second tarsal segments with ventral hairs on proximal 0.6. Cauda with 9-18 hairs	…..12
11	ANT III with strongly protruberant rhinaria maximally 16-20 μm in diameter, and almost rimless, so that edge of dome of rhinarium forms a smooth continuum with raised cuticle surrounding it (Fig. 49b)	…..Uroleucon gravicorne
–	ANT III with rhinaria maximally 8-15 μm in diameter, each surrounded by a shelf-like ridge, from which the dome of the rhinarium arises almost perpendicularly (the more normal condition of the genus; Fig. 49c)	…..Uroleucon cadens
12	HT II 0.09-0.105 mm, shorter than maximum width of hind femur. ABD TERG 8 with 5-9 hairs. SIPH 1.6-1.7 × cauda, which is not attenuated distally	…..Uroleucon brevitarsus
–	HT II 0.125-0.17 mm, longer than maximum width of hind femur. ABD TERG 8 with 4 hairs. SIPH 1.1-1.3 × cauda, which is attenuated distally	…..13
13	Paired spinal tubercles (STu) usually present on most or all of ABD TERG 2-7 (occasionally absent from some specimens)	…..Uroleucon caligatum
–	STu absent	…..Uroleucon luteolum
14	Cauda black like SIPH. Tibiae with pale section in middle	…..15
–	Cauda pale or dusky, distinctly paler than SIPH (or if rather dark then tibiae are entirely black)	…..17
15	SIPH less than 1.3 × cauda , with reticulation on distal 0.33-0.4 of length	…..Uroleucon amamianum
–	SIPH more than 1.3 × cauda, with reticulation on distal 0.2-0.33 of length	…..16
16	Primary rhinarium on ANT V 25-40 μm long (Fig.49d). ANT III either wholly dark, or infuscated in rhinariated section, which is swollen, usually to 1.25-1.6 × BD III	…..Uroleucon solidaginis

–	Primary rhinarium on ANT V 16-27 μm long. ANT III pale or dusky with rhinariated part only slightly swollen, to less than 1.25 × BD III	…..Uroleucon lactucicola
17	R IV+V more than 1.65 × HT II, with at least 17 accessory hairs	…..Uroleucon astronomus
–	R IV+V 0.86-1.55 × HT II	…..18
18	SIPH 0.82-1.11 × cauda. R IV+V 0.86-1.12 × HT II. Dorsal hairs all arise from conspicuous blackish scleroites	…..Uroleucon lanceolatum
–	SIPH 1.15-1.8 × cauda. R IV+V 0.95-1.55 × HT II. Scleroites at bases of dorsal hairs are pale, dusky or dark	…..19
19	Tibiae entirely dark	…..20
–	Tibiae pale, or with distinctly paler proximal section	…..23
20	Cauda with 13-20 hairs	…..21
–	Cauda with 22-32 hairs	…..22
21	ANT III with 13-47 rhinaria (rarely less than 20). ABD TERG 8 with (3-) 4 hairs. First tarsal segments with (4-) 5 hairs	…..Uroleucon atripes
–	ANT III with 7-16 rhinaria. ABD TERG 8 with 2 (-4) hairs. First tarsal segments with 3 (-4) hairs	…..Uroleucon nigrotibium
22	Coxae and cauda both dusky/dark compared with bases of femora. ANT III with 9-24 rhinaria, usually confined to basal 0.33-0.5	…..Uroleucon vancouverense
–	Coxae and cauda similar in pigmentation to bases of femora. ANT III with 15-38 rhinaria, usually extending onto distal half	…..Uroleucon nigrotuberculatum
23	R IV+V 1.30-1.55 × HT II. Cauda with 10-18 hairs	…..24
–	R IV+V 0.95-1.25 × HT II. Cauda with 10-42 hairs	…..26
24	ANT III with 5-9 rhinaria clustered on basal half. SIPH only a little longer than cauda, which bears 10-13 hairs. BL not more than 2 mm	…..Uroleucon solirostratum*
–	ANT III with 12-36 rhinaria usually extending onto distal half. SIPH at least 1.33 × cauda, which bears 12-18 hairs. BL at least 2 mm	…..25
25	ABD TERG 2-4 usually with small marginal tubercles (MTu). Hind femur with a rather abrupt transition from pale to black on distal 0.20-0.25 of length. BL 2.8-3.4 mm	…..Uroleucon sijpkensi

–	MTu absent. Hind femur shading gradually from pale to dusky brown at apex. BL 2.0-2.6 mm	…..Uroleucon arnesense
26	Cauda with 10-17 hairs	…..Uroleucon boreale
–	Cauda with (15-)20-42 hairs	…..27
27	ANT III with 7-17 rhinaria restricted to basal 0.4	…..Uroleucon olivei
–	ANT III usually with 20-46 rhinaria extending onto distal half (midsummer dwarf individuals may have fewer)	…..28
28	R IV+V 1.05-1.25 × HT II. Small marginal tubercles (MTu) sometimes present on some of ABD TERG 2-4	…..Uroleucon pieloui
–	R IV+V 0.95-1.10 × HT II. MTu absent	…..Uroleucon gigantiphagum
29	SIPH black and very markedly swollen, with maximum width of swollen part 2.2-3.2 × minimum width near base. ANT with numerous sec. rhinaria; III 37-40, IV 1-7, V 0-1	…..Hyperomyzus inflatus
–	SIPH pale or dark, tapering, cylindrical, or swollen to a lesser extent. ANT with sec. rhinaria III 0-12, IV 0-6, V 0-5	…..30
30	Head spiculose, with well-developed, steep-sided ANT tubercles	…..go to key to polyphagous aphids, starting at couplet 5
–	Head smooth with ANT tubercles undeveloped or weakly developed	…..31
31	Spiracular apertures rounded. ABD TERG 1 and 7 without marginal tubercles (MTu). Cauda short, helmet-shaped or triangular, less than 1.4 × its basal width in dorsal view, with 4-6(-8) hairs	…..32
–	Spiracular apertures small and reniform. ABD TERG 1 and 7 with MTu. Cauda tongue- or finger-like or, if less than 1.4 × its basal width then with more than 10 hairs	…..38
32	SIPH swollen or cylindrical, smooth and slightly constricted subapically, and with a smooth rounded swollen flange, giving it a knob-like apex. ANT III with 0-7 rhinaria, 0 on IV	…..33
–	SIPH conical or tapering with a sharply defined subapical annular incision, and flange not swollen. ANT III with or without rhinaria, but if with then there are also some on IV	…..35
33	Metanotum and ABD TERG 1-6 completely covered by a solid dark shield. SIPH dusky/dark, only slightly swollen, with maximal width of swelling on basal half (Fig.49f). ANT PT/BASE 3.4-5.2	…..Cachryphora canadensis
–	No solid dark dorsal shield. SIPH distinctly swollen, with maximal width of swelling at midlength or on distal half (e.g. Fig.49e). ANT PT/BASE 2.2-3.9	…..34
34	R IV+V 1.05-1.25 × HT II. ANT PT/BASE 2.2-3.2. Prosternum with spinulose imbrication	…..Cachryphora imbricaria
–	R IV+V 1.25-1.45 × HT II. ANT PT/BASE 2.9-3.9. Prosternum not spinulose	…..Cachryphora serotinae
35	ANT with 1-15 rhinaria on III and 4-11 on IV	…..36
–	ANT III and IV without rhinaria	…..37
36	Cauda shorter than its basal width. Longest hairs on ANT III 27-50 μm, c. 2 × BD III. Dorsum usually with a solid black shield	…..Acuticauda solidaginifoliae
–	Cauda longer than its basal width. Longest hairs on ANT III 8-16 μm, shorter than BD III. Dorsum without a solid black shield	…..Acuticauda asterensis
37	Dorsal abdomen with an extensive solid black shield. ANT III 0.31-0.47 mm, 2.4-3.4 × HT II. R IV+V 0.17-0.24 mm. SIPH dark, imbricated, 1.7-3.4 × cauda	……Brachycaudus cardui
–	Dorsal abdomen without a black shield. ANT III 0.07-0.25 mm, 0.9-2.2 × HT II. R IV+V 0.10-0.15 mm. SIPH pale, smooth, 0.8-2.0 × cauda	……Brachycaudus helichrysi
38	Dorsum with an extensive black sclerotic shield	…..39
–	Dorsum without an extensive black shield	…..40
39	ANT hairs very long and fine, those on III more than 2 × BD III. Cauda with c.15-17 hairs	…..Aphis tsujii
–	Longest hairs on ANT III 0.3-0.8 × BD III. Cauda with 4-9 hairs	…..Aphis craccivora
40	Well-developed MTu consistently present on ABD TERG 2-5 as well as 1 and 7	…..41
–	MTu only consistently present on ABD TERG 1 and 7	…..42
41	ANT 5-segmented. Dorsal abdomen without any dark markings. Longest hairs on ANT III 0.4-0.9 × BD III	…..Aphis solidagophila*
–	ANT 6-segmented. ABD TERG 7 and 8 (at least) with black cross-bands. Longest hairs on ANT III (presumably) more than 0.8 × BD III	…..Aphis solidaginis*
42	SIPH black, 0.24-0.40 × BL, c.2 × the much paler cauda. Head, ANT I, II and basal part of III very pale, contrasting with dark rest of ANT. Hairs on ANT III minute, the longest less than 0.4 × BD III	…..Aphis coreopsidis
–	Without that combination of characters	…..go to key to polyphagous aphids, starting at couplet 25

*Solidaster* (Solidago × Aster hybrid)	Asteraceae
	Uroleucon nigrotuberculatum

*Soliva*	Asteraceae
Soliva anthemifolia	Pemphigus sp. (as betae); Rhopalosiphum rufiabdominale

Use key to polyphagous aphids.

*Sollya* see Billardiera	Pittosporacaeae
*Sollya fusiformis* = Billardiera fusiformis

*Sonchus*	Asteraceae
Sonchus acaulis	Macrosiphum euphorbiae
S. arvensis (incl. ssp. uliginosus)	Acyrthosiphon [malvae], scariolae;
	Aphis craccivora, [elongata], fabae, gossypii, [jacobaeae],
	spiraecola;
	Brachycaudus cardui, helichrysi; [Capitophorus elaeagni];
	Dysaphis radicivorans;
	Hyperomyzus carduellinus, lactucae, pallidus;
	Macrosiphum euphorbiae; Myzus ornatus, persicae;
	Pemphigus [borealis], bursarius, [ fuscicornis],
	[matsumurai];
	Protaphis [anuraphoides], scorzonerae; Protrama radicis;
	Trama caudata, [mordvilkoi], [muchinae], [nigrarta],
	troglodytes;
	Uroleucon [aeneum], [carthami], cichorii, formosanum,
	[mulgedii], [murale], picridis, sonchi, Uroleucon
	(Uromelan) sp. (as solidaginis – perhaps compositae)
S. asper (incl. ssp. glaucescens)	[Acyrthosiphon gossypii, vasiljevi];
	Aphis craccivora, fabae, gossypii, [sonchi];
	Aulacorthum solani; Brachycaudus cardui;
	Hyperomyzus carduellinus, lactucae, pallidus;
	Macrosiphum euphorbiae; Myzus ornatus, persicae;
	Nasonovia ribisnigri; Neomyzus circumflexus;
	Pemphigus bursarius;
	[Protaphis sonchi], [Protaphis sp. (Bozhko 1976a, 80)];
	Protrama flavescens, [longitarsus ssp. sclerodensis],
	radicis;
	Trama caudata, maritima, [mordvilkoi], troglodytes;
	Uroleucon ambrosiae, [bicolor], cichorii, compositae,
	formosanum, [fotedari (Bhagat 1981b; nomen nudum)],
	sonchellum, sonchi, [tussilaginis]
S. brachyotus	Brachycaudus cardui;
	Hyperomyzus carduellinus, lactucae;
	Myzus ornatus; Uroleucon sonchi
S. caudatus (?)	Uroleucon sonchi
S. congestus	Hyperomyzus lactucae; Uroleucon sonchi
S. cornutus	Aphis gossypii; Protaphis kenanae
S. exauriculatus = S. cornutus
S. fruticosus	Aphis gossypii; Hyperomyzus lactucae;
	Macrosiphum euphorbiae; Myzus ornatus;
	Uroleucon picridis
S. glaucescens = S. asper ssp. glaucescens
S. hydrophilus	Hyperomyzus lactucae
S. lachnocephalus	Aphis gossypii; Macrosiphum euphorbiae
S. lactucoides	Uroleucon formosanum
S. leptocephalus	Aphis gossypii
S. luxurians	Aulacorthum solani; Hyperomyzus carduellinus;
	Macrosiphum euphorbiae;
	Uroleucon compositae, sonchi
S. macrophyllus see Lactuca macrophylla
S. maritimus	Aphis fabae; Hyperomyzus lactucae;
	Nasonovia ribisnigri; Protaphis terricola;
	Uroleucon sonchi
*S. megalocarpus*	Hyperomyzus carduellinus, lactucae
S. nanus = Launaea nana
*S. oleraceus*	Acyrthosiphon ghanii, [gossypii], ilka, lactucae, [pisum],
	rubi;
	Anaulacorthum zhangjiajiense;
	Aphis aurantii, coreopsidis, craccivora, fabae, gossypii,
	[molluginis], nerii, [sambuci], solanella,
	spiraecola, [Aphis sp. (Millar 1994)];
	Aulacorthum solani; Brachycaudus helichrysi;
	[Brevicoryne brassicae];
	Hyperomyzus carduellinus, lactucae, pallidus;
	Macrosiphum euphorbiae; Myzus ornatus, persicae;
	Nasonovia ribisnigri; Neomyzus circumflexus;
	Pemphigus bursarius;
	Protaphis kenanae, pseudocardui, [sonchi], terricola;
	Protrama flavescens;
	Trama caudata, maritima, [mordvilkoi], troglodytes;
	Uroleucon ambrosiae, [carthami], cichorii, compositae,
	formosanum, pseudambrosiae, sonchellum, sonchi
	[Utamphorophora commelinensis]
S. palmensis	Uroleucon sonchi
*S. palustris*	Aphis craccivora; Hyperomyzus lactucae, pallidus;
	Uroleucon sonchi
S. radicatus	Hyperomyzus lactucae; Uroleucon sonchi
S. squarrosus = S. fruticosus
S. tenerrimus	Aphis fabae; Hyperomyzus lactucae; Protaphis terricola;
	Uroleucon compositae, sonchi
S. tuberifer	Hyperomyzus lactucae; Uroleucon sonchi
S. uliginosus = S. arvensis ssp. uliginosus
*S. wilmsii*	Uroleucon sonchi
Sonchus spp.	Acyrthosiphon [pisum], rubi; [Aphis exsors];
	[Capitophorus carduinus]; [Chaitomyzus rhododendri];
	[Cryptosiphum artemisiae]; [Forda formicaria];
	[Hayhurstia atriplicis]; Myzus ascalonicus;
	[Nasonovia compositellae]; Pseudomegoura magnoliae;
	[Sitobion rosaeiformis]; Smynthurodes betae;
	Uroleucon aeneum, [eupatoricolens], gravicorne, [jaceae]

Key to apterae on Sonchus:-

1	Hind tarsus II elongate, more than 0.5 × hind tibia	…..2
–	Hind tarsus II of normal length, similar to fore and mid tarsi	…..6
2	SIPH completely absent. Eyes of 3 facets	…..Trama troglodytes
–	SIPH present as slightly raised pores. Eyes usually with more than 12 facets	…..3
3	ANT VI similar in length to ANT V or a little longer, with PT at least one third as long as BASE VI. Many apterae alatiform with dark tranverse bands on dorsal abdomen	…..4
–	ANT VI a little shorter than ANT V, with PT very short. No dorsal abdominal pigmentation	…..5
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 0.59-0.70 × length of hind tibia. Hind tibia 6.5-9.2 × ANT IV. R IV with 6-8 accessory (dorsal) hairs	…..Protrama flavescens
5	ANT III 2.3-2.9 × ANT IV. HT II 3.3-4.2 × ANT VI (incl. PT)	…..Trama maritima
–	ANT III 1.6-2.25 × ANT IV. HT II 2.6-3.5 × ANT VI incl. PT	…..Trama caudata
6	SIPH with a subapical zone of polygonal reticulation occupying 0.12-0.43 of total length	…..7
–	SIPH (if present) without any subapical polygonal reticulation, or with striae containing a few closed cells but occupying less than 0.1 of total length	…..17
7	SIPH pale, sometimes dusky towards apices, with reticulation of large polygonal cells on distal 0.12-0.20 of length	…..Macrosiphum euphorbiae
–	SIPH black, with reticulation of numerous rather small polygonal cells on distal 0.16-0.43 of length	…..8
8	SIPH pale on basal 0.2-0.3 of length. Second tarsal segments with proximal ventral hairs atrophied	…..Uroleucon gravicorne
–	SIPH entirely dark. Second tarsal segments with proximal ventral hairs normally developed	…..9

9	Cauda almost as dark as SIPH	…..10
–	Cauda much paler than SIPH	…..11
10	ANT III with 48-86 rhinaria extending over 0.85-0.92 of length of segment. ANT III 1.8-2.5 × ANT V. Cauda with 10-22 hairs. ABD TERG 2-4 without marginal tubercles (MTu)	…..Uroleucon compositae

–	ANT III with 20-45 rhinaria on basal 0.35-0.52 of length. ANT III 1.4-1.9 × ANT V. Cauda with 20-34 hairs. ABD TERG 2-4 regularly with MTu (90% with 5 or more), often larger than hair bases	…..Uroleucon aeneum
11	ANT III 1.5-2.0 × longer than ANT IV+V together	…..12
–	ANT III less than 1.2 × ANT IV+V together	…..13
12	ANT III with 96-135 strongly protruberant rhinaria. Cauda 1.3-1.9 × ANT V. ANT PT/BASE 4.8-6.3	…..Uroleucon formosanum
–	ANT III with 49-93 rhinaria, which do not protrude strongly. Cauda 0.85-1.3 × ANT V. ANT PT/BASE 6.0-8.4	…..Uroleucon sonchellum
13	R IV+V 0.73-0.88 × HT II. Dorsal hairs on ABD TERG 1-5 usually not on dark scleroites, or on very small scleroites. Coxae dark	…..Uroleucon sonchi
–	R IV+V 0.9-1.84 × HT II. Dorsal hairs on ABD TERG 1-5 all or mostly placed on dark scleroites. Coxae pale or dark	…..14
14	Crescent-shaped black antesiphuncular sclerites present. ANT III with 25-97 secondary rhinaria occupying at least 0.8 of segment	…..15
–	Antesiphuncular sclerites absent or indistinct. ANT III with 8-46 secondary rhinaria on basal 0.5-0.7 of segment	…..16
15	R IV+V 1.45-1.84 × HT II	…..Uroleucon picridis
–	R IV+V 1.17-1.33 × HT II	…..Uroleucon cichorii
16	HT II rather long and thin, about 6 × its maximum thickness, and 0.9-1.1 × R IV+V	…..Uroleucon pseudambrosiae
–	HT II shorter, less than 5 × its maximum thickness and 0.7-0.85 × R IV+V	…..Uroleucon ambrosiae
17	SIPH markedly clavate. ANT III with 4-40 rhinaria	…..18
–	SIPH (if present) cylindrical, tapering, or if clavate then ANT III with 0-3 (-9) rhinaria	…..20
18	Hairs on ABD TERG 8 are 8-19 μm long, and on ANT tubercles 6-11 μm. Secondary rhinaria distributed ANT III 11-29, IV (0)-1-16, V 0 (-9). ANT PT/BASE 4.3-5.6. ANT PT 1.6-2.3 × cauda	…..Hyperomyzus carduellinus
–	Hairs on ABD TERG 8 are 30-50 μm long, and on ANT tubercles 18-30 μm. Secondary rhinaria distributed III 4-40, IV 0-2, V 0. ANT PT/BASE 4.8-7.9. ANT PT 2.0-3.0 × cauda	…..19
19	SIPH 3-5 × longer than maximum width of swollen part, which is 1.6-2.4 × minimum width on basal part. R IV+V 0.9-1.12 × HT II (mostly 0.95-1.1 ×). (Al. with a compact black solid trapezoid dorsal abdominal patch, with hardly any perforations)	…..Hyperomyzus pallidus
–	SIPH 4-7 × longer than maximum width of swollen part, which is 1.3-2.0 × minimum width on basal part. R IV+V 0.8-1.07 × HT II (mostly 0.9-1.0 ×). (Al. with a very irregular and variably shaped dorsal abdominal patch, interrupted by extensive perforations)	…..Hyperomyzus lactucae
20	Head spiculose with well-developed ANT tubercles, with inner faces scabrous and parallel or apically convergent	…..21
–	Head without spicules, and ANT tubercles if well developed then with inner faces divergent	…..23
21	Abdomen with a dark dorsal abdominal patch. SIPH tapering/cylindrical	…..22
–	Without that combination of characters	…..go to key to polyphagous aphids, starting at couplet 5
22	ANT III with 6-9 rhinaria (al. with 22-23 on III and 7-9 on IV)	…..Anaulacorthum zhangjiajiense
–	ANT III with 0-3 rhinaria (al. with 14-28 on III and 2-8 on IV)	…..Neomyzus circumflexus
23	Head with well-developed ANT tubercles, their inner faces smooth and divergent. SIPH long, tubular and pale, or only dark towards apices	…..24
–	Head with ANT tubercles undeveloped or weakly developed. If long SIPH are present then they are entirely dark	…..28
24	Thoracic spiracles enlarged, much larger than abdominal spiracles. ANT PT/BASE 7.0-11.4, usually more than 8.0. Hairs on ANT III 0.7-1.1 × BD III. Dorsum usually with paired dark intersegmental markings	…..Nasonovia ribisnigri
–	Thoracic spiracles similar in size to abdominal ones. ANT PT/BASE less than 7.5. Hairs on ANT III less than 0.7 × BD III. Dorsum without any dark markings	…..25
25	R IV+V with 16-25 accessory hairs	…..Acyrthosiphon lactucae/scariolae group
–	R IV+V with 6-11 accessory hairs	…..26
26	ANT III with 4-11 rhinaria in a row extending over 0.33-0.9 of its length. ANT PT/BASE 2.5-3.5	…..Acyrthosiphon ghanii
–	ANT III with 1-5 rhinaria clustered near base. ANT PT/BASE 3.0-6.0	…..27
27	Dorsal cuticle papillated or wrinkled. Cauda dusky, with 7-10 hairs	…..Acyrthosiphon rubi

–	Dorsal cuticle smooth. Cauda pale, with 5-8 hairs	…..Acyrthosiphon ilka
28	ANT PT/BASE 0.7-1.4. R IV+V longer than the very short dark tubular SIPH	…..29
–	ANT PT/BASE either less than 0.5 or more than 1.5. R IV+V shorter than SIPH (or SIPH absent)	…..31
29	Cauda with 7-10 hairs	…..Protaphis scorzonerae
–	Cauda with 12-25 hairs	…..30
30	ANT PT 0.75-1.05 × SIPH. ANT PT/BASE 0.8-1.0	…..Protaphis terricola group (incl. kenanae)

	– ANT PT 1.06-1.4 × SIPH. ANT PT/BASE 1.0-1.4	…..Protaphis pseudocardui
31	Cauda helmet-shaped, about as long as its basal width, with 4-8 hairs	…..32
–	Cauda either not developed at all or much longer than its basal width, tongue- or finger-shaped, with 4-26 hairs	…..34
32	Head and ABD TERG 8 or 7-8 with spinal tubercles (STu), and large MTu also present on most segments. SIPH without a subapical annular incision. Spiracular apertures reniform	…..Dysaphis radicivorans*
–	STu absent, and MTu of only sporadic occurrence. SIPH with a subapical annular incision. Spiracular apertures large and rounded	…..33
33	Dorsal abdomen with an extensive solid black shield. ANT III 0.31-0.47 mm, 2.4-3.4 × HT II. R IV+V 0.17-0.24 mm. SIPH dark, imbricated, 1.7-3.4 × cauda	……Brachycaudus cardui
–	Dorsal abdomen without a black shield. ANT III 0.07-0.25 mm, 0.9-2.2 × HT II. R IV+V 0.10-0.15 mm. SIPH pale, smooth, 0.8-2.0 × cauda	……Brachycaudus helichrysi
34	ANT III-VI dark, contrasting with pale ANT I-II and head. SIPH long, thin and black, 0.24-0.4 × BL, contrasting with pale cauda	…..Aphis coreopsidis
–	Without that combination of characters	…..go to key to polyphagous aphids, starting at couplet 24

Sophia Adams nec L. see Descurainia

Brassicaceae

Sophia L. see Pachira

Malvaceae

*Sophora*	Fabaceae
Sophora *alopecuroides*	Acyrthosiphon gossypii, pisum, sophorae;
	Aphis craccivora, solanella
*S. japonica*	Pagoda Tree
	Acyrthosiphon gossypii, sophorae;
	Aphis craccivora, cytisorum, fabae, gossypii, odinae;
	Appendiseta robiniae; Tinocallis sophorae;
*S. mollis*	Acyrthosiphon sophorae
S. moorcroftiana	Aulacorthum solani; Macrosiphum euphorbiae;
	Myzus persicae
S. pachycarpa	Acyrthosiphon gossypii; Aphis craccivora
*S. secundiflora*	Aphis gossypii
*S. tomentosa*	Acyrthosiphon gossypii

Key to species on Sophora (tentative, as host-specific species have not been seen by authors):-

1	All viviparae alate. Cauda knobbed, anal plate bilobed. Secondary rhinaria on ANT III transversely elongate. ANT PT/BASE about 0.5. SIPH as short, truncated cones	…..2
–	Viviparae apterous or alate. Cauda tongue- or finger-shaped, anal plate entire. ANT PT/BASE more than 2. SIPH tubular	…..3
2	SIPH with a single hair appended at base. ABD TERG 1 and 2 without conical tubercles. Head and prothorax without a dark median longitudinal stripe	…..Appendiseta robiniae
–	SIPH without an appended hair. ABD TERG 1 and 2 with paired conical tubercles. Head and prothorax with a thin dark median longitudinal stripe	…..Tinocallis sophorae*
3	SIPH and cauda pale, antennal tubercles well developed, smooth and divergent. SIPH without subapical polygonal reticulation	…..4
–	If SIPH and cauda are both pale then either antennal tubercles are steep-sided or convergent and scabrous/spiculose, or SIPH have subapical polygonal reticulation	…..6
4	SIPH 0.4-0.5 × BL	…..Acyrthosiphon gossypii
–	SIPH 0.26-0.35 × BL	…..5
5	SIPH about 2.5 × longer than cauda. ANT PT about 5 × longer than R IV+V	…..Acyrthosiphon sophorae*
–	SIPH 1.2-1.7 × longer than cauda. ANT PT 7.5-10 × longer than R IV+V	…..Acyrthosiphon pisum
6	SIPH pale or dark, cauda pale or dusky. Dorsal abdomen without extensive black sclerotisation	…..go to key to polyphagous aphids
–	SIPH and cauda both black. Dorsal abdomen usually with extensive black, reticulate sclerotisation	…..7
7	BL divided by R IV+V less than 3.2 + (6 × BL)	…..Aphis cytisorum
–	BL divided by R IV+V more than 3.2 + (6 × BL)	…..Aphis craccivora