364 APHIDS OF THE ROCKY MOUNTAIN REGION 
northern part of state. Colorado: Buckhorn Creek near Masonville), Longmont 
and Monte Vista. Fundatrices June 24 to July 4, alate fundatrigeniae July 4 and 
(dead specimens in gall) Aug. 18; rare. 
This species is very close to P. populi-caulis and only doubtfully separated 
by host, shape of gall which is without definite round exit hole and length of 
III in fundatrigenia (not distinctly longer than hind tarsal I, longer than hind 
tarsal II in P. populi-caulis). 
Pemphigus populi-ramulorum Riley 
The Poplar Twig-gall Aphid 
Pemphigus populi-ramulorum Riley, 1879:16; Thomas, 1879:209; tackwer 1908a:208; 
Gillette and Palmer, 1934:227. 
Fundatrix. Pale creamy yellow; appendages dusky. Body length 2.5-3; hind tibia .40- 
.50; hind tarsal II .13; antenna .32-.37; rostrum rarely attaining 2d coxa. Gland plates on 
dorsum in 6 longitudinal rows. . 
Alate Vivipara. Fundatrigenia. Head and thorax black; abdomen dark olive; append- 
ages dusky. Body length 2.25; fore wing 3-3.5, hamuli 2 in number; hind tibia .60-.70; hind 
tarsal II .15; antenna .61-.68. Cornicle plainly evident. Rostrum attaining between Ist and 
2d coxae. 
Fundatrix : 
i a emenag amr Pe Say 
06 613-15} (.07-.09) +02 --.09--! 
Fundatrgenia Hd. Ta. 
Cross vein 
arise to Sther or 
| ER: 
G22= 95) ace Gog -.12) ( +.03 
: 7) apart both wittgs- 
I \y 
Gen.o-5 (een. 29" (Sen.o-4)" *7 
Fig. 438. Pemphigus populi-ramulorum 
Gall. Green. Normally globular with transverse mouth, about 25 mm in diameter. In cases 
of heavy infestation some galls are elongated and some occur on petioles where they differ 
from galls of P. populi-transversus by protruding upper lip. Normally located on stem of twig 
at base of petiole. 
Collections. As winter host on Populus sargenti and P. “balsamifera” (prob- 
ably P. candicans or deltoides), in twig and sometimes petiole galls; summer 
host unknown. Throughout region. Fundatrices June 8 to July 22, alate funda- 
trigeniae June 8 to Aug. 14; rather common. 
Chief Distinguishing Characters. Character of gall, presence of secondary 
sensoria on all antennal segments, but fewer than 7 on IV, length of ITI (.22-.25 
in fundatrigenia, about .14 in fundatrix). 
Pemphigus populi-transversus Riley 
The Poplar Leaf-stem Gall Aphid 
Pemphigus populi-transversus Riley, 1879:15; Thomas, 1879:208; Oestlund, 1887:21; 
Jackson, 1908a:206; Jones and Gillette, 1918: 577 (life history) ; Gillette and 
Palmer, 1934:228. 
Fundatrix. Whitish to pale sordid greenish yellow; powdery; black on head, rostrum 
and appendages. Body aean 2.6-3; hind tibia .45-.55; hind tarsal II .13-.15; antenna 36. 
eee 
MN) 14-16) F G03-+.04) 
4 ‘® wn A) iy) 
G17-.20KSen.5-1) (.09-10)08 --o§ (12.— 13) 
13) ¢ ale 
7 8 on) +.02 
4-02~.03), 08s 
Fig. 439. Pemphigus populi-transversus 
Alate Vivipara. Fundatrigenia. Head and thorax black; abdomen sordid pale greenish 
yellow; rostrum and appendages blackish. Body length 1.7-2; wing 2.9-3; hamuli 2-3 in num- 
ber; hind tibia .50-.65; hind tarsal II .15-.17; antenna .53-.63. Sexupara. Same as funda- 
trigenia excepting antenna which is slightly longer. 
