SUBFAMILY ERIOSOMATINAE 359 
Key to Species of Pemphigus 
(Based on alatae from galls unless otherwise stated.) 
1. Secondary sensoria usually absent or but 1 on V and VI eachoece.......-...--ccee-ceeeeceonseceececeeceescees 2 
. Secondary sensoria usually present (2 or more) on V and WJoo..u.0......0.--0eccceceeeeceeceereseoreceeceeees 4 
2. Permanent sensorium on VI unusually large and containing 
EA EAUMCNEU EERE OUUCLS 700), 5SO4 ) fs eo ecee epee enrccn ramet yhcte gods Mecomech nadasyeceee populi-transversus 
.-- Permanent sensorium at base of VI not unusually large....................::csccsscceeceeeceeecececesecneceesee 3 
SL Tee t= LOPLON SSC TMS OL) foie etree csterccsies cep ocntssccrtancesias souct aces stot bate cs cece Toe abner bat tucdetea stamens monophagus 
AM Pere CECAN IT CONE SSO Ye cre cence cn cy ates towers ances en nos waar ovnarnioy cnet ov eas eaeasak peceneipucrasiosobopecos balsamiferae 
4. Secondary sensoria 7 or more on VI (p. 362) ..........-- i 53 Sit Dalat Ve alone ober Ait al nortonii 
PRPPTIMEEICL OLY SENGUPTA TOWEL CHAN 7 ORV Lcccecccstcs tes ccuccee ceca steset ce cee evap saeacceceap vcs stcscades cavenr fasecasncbaneceosss 5 
5. III longer than IV+V, secondary sensoria more or less 
CE Eas Fa GSB LoS Mes Se a Sg re a cp ee a junctisensoriatus 
... III not longer than IV-+V, sensoria not coalesced.........:c..c:-csssecsscssccsessecsssseeessesesesesenesacenencssees 6 
6. Alata not smaller than 2, fundatrix not smaller than 3 (p. 364)................ populi-ramulorum 
.- Alata usually smaller than 2, fundatrix smaller than 3....2...2.........c.:cscceccescescsssecscesenceeceecsosensees 7 
7, EAT distinctly longer than hind tarsal TV;.22c.-o2c...-.cccccec.cccnccececapeesceepes are A Oe ASEM beth AT He 8 
fo orn) mot noticeably longerthan hind tarsal Uo foo 2052 scsstenscleseosecysoceoncssttopin-ccctecaysoenparasesnan 9 
8. In petiole galls on Populus (European specics) (p. 360) ..............::.::ccscscceesceeesceeeeees bursarius 
In petiole and leaf galls on Populus sargenti (American species) 
CBE IS cos che Mla WR Pele aban nembeie tame ck ee ike sd Sa NEE RES J populi-caulis 
9. In gall on upperside of leaf of Populus angustifolia; hind tarsus in 
PRMM METIS NOS TON eer them LLL (P.0 SGS ) es ssss ones csngent yes ces tgrs care sersavseenpncncdctneowonsorneesunaeeeseny, populi-venae 
In petiole and leaf gall on Populus angustifolia; hind tarsus in 
CGS ROL Eg ge ETS GO LY OTe cop ce in ee sa We SE ee a a populi-globuli 
Pemphigus balsamiferae Williams 
The Poplar Sugar-Beet Root Aphid (Plate VIII) 
Pemphigus balsamiferae Williams, 1910:8; Davis, 1911b:4; Maxson, 1917: Mar. 17, 
in Ror aeeercencs with Gillette; Gillette and Palmer, 1934: 222; Maxson, 1948:106 
an 1 
Pemphigus betae Doane (questionable identification), Gillette and Bragg, 1915a:97; 
Maxson and Knowlton, 1929:267; Maxson, 1916:500. 
Wax Gland 
<i cakes dat i= : 
\ J 13) €07-" sate Se ase ae Devt 
Alate Fundatrigenia eek: ea = 
Se ese eB ne 
-./ 03 
IPRS 234) 
G 
§ 523) (sen-7- ~11) (08--/2) (= 15) 
On Beet 
fos 
Apt: visoges 
aa 9 eases ha 
(09-12) 605-07(.10-.13 ++ +03) 
Mong arb OTA) ss 
3 f EE — _ 
Side TI) ono Populus 
of leaf e 
Gall x % 
Fig. 431. Pemphigus balsamiferae 
Fundatrix. Newly Hatched. Light chrome-yellow to dusky greenish, with dark greenish 
blotch posteriorly and abdomen with 6 longitudinal rows of dusky spots; appendages blackish. 
Body length .54. Adult. Pale greenish yellow; appendages dark. Body length 2.3-2.5; hind 
tibia .35-.48; hind tarsal II .10-.12; antenna .26-.34; rostrum nearly attaining 2d coxa. Wax 
glands not evident on head, present on body. 
Alate Vivipara. Fundatrigenia (Leaving Populus), Head and thorax black; abdomen 
dull green to yellow; powdery; appendages dusky. Body length 1.5; hind tibia .55-.77; an- 
tenna .60-.84, fore wing 2.42; hamuli 2-3 in number; rostrum hardly attaining 2d coxa. Sexu- 
para (on beet roots, returning to Populus). Same as fundatrigenia or darker, even blue-black, 
and with tuft of cotton on metathorax, abdominal I and tip of abdomen and antenna usually 
shorter and sensoria fewer as shown in figure. 
Apterous Vivipara. Summer Form (On beet roots). Sordid white to yellow-green; with 
dusky patch on head; appendages dusky. Body length 1.5-2.5; hind tibia .35-.48; hind tarsal 
II .10-.12; antenna .37-.46; rostrum as in fundatrix. Hibernating Vivipara (In soil). Body 
length 2; hind tibia .35-.50; hind tarsal II .11-.15; antenna .36-.50; rostral IV+V .10 attaining 
2d coxa. Cornicle a mere ring. 
