SUBFAMILY ERIOSOMATINAE 363 
Pemphigus populi-caulis Fitch 
Poplar Leaf-petiole Gall Aphid 
Pemphigus populicaulis Fitch, 1859:845; Thomas, 1879:149; Jackson, 1908a:191; Dav- 
idson, 1915:420; Maxson ‘and Knowlton, 1929:254; Gillette and Palmer, 1934 :226. 
Fundatrix. Pale yellowish to creamy; pruinose; appendages slightly dusky. Body length 
2-2.9; hind tibia .35-.40; hind tarsal II .12; antenna .30-.36; rostrum attaining between Ist and 
2d coxae. Wax glands in 6 dorsal rows; none on head. 
Alate Vivipara. Blackish brown on head and thorax; abdomen yellowish olive-green; 
appendages dusky brown. Body length 1.7-2; across eyes .33-.38; fore wing 2.6-3; hamuli 2-3; 
hind tibia .50-.70; antenna .66-.76; rostrum attaining between Ist and 2d coxae. 
Gall. Yellowish green to creamy, formed of swollen base of leaf twisted with broadened 
petiole; exit a small round hole on underside between leaf and petiole. Size 10-13 mm in 
diameter. 
28 aie ear ore o 
} Dui Dea nudrieia's! 
Sa _ sant a a =15) ~ 
—_ 
“Cenita/ 
<a.p orifice 
(13-1 "n Ca. THe view) 
Fig. 436. Pemphigus populi-caulis 
Cellections. As winter host on Populus sargenti and rarely P. acuminata, in 
twisted petiole and leaf galls; alternate host unknown. 
Throughout Colorado and nothern Utah. Fundatrices June 12 to Aug. 29, alate 
fundatrigeniae June 20 to Aug. 29; common. 
Chief Distinguishing Characters. Character, of gall with round exit hole, 
length of antenna (III not longer than .12 in fundatrix, not exceeding .23 in 
alata), number of sensoria on antenna especially on VI (on latter less than 7). 
This species is very close to P. bursarius (Linnaeus) and distinguished most 
certainly by form of gall. However, a number of collections of specimens ap- 
parently inseparable from P. populicaulis have been taken in petiole galls re- 
sembling those of P. populi-transversus. Galls of P. bursarius according to Tull- 
gren (1909:114) and Theobald (1929:245) differ in more protruding lips. The 
question of the status of these forms requires further biological work. 
Pemphigus populi-globuli Fitch 
The Poplar Bullet Gall Aphid 
Pemphigus populi-globuli Fitch, 1859:850; Thomas, 1879:153; Jackson, 1908a:196; 
axson and Knowlton, 1929: 254 and 261; Gillette and Palmer, 1934 :226. 
Fupdatrix 
ge7 1) - «02 (_ 
cosepidh ee toe aig yeas 
Sa inininiipaliin Siti me= 
716-16 bens 10X08-IN.09-1 (13-15) + 03 
Fig. 437. Pemphigus populi-globuli 
Fundatrix. Wax glands present on entire body. Dark green; head, rostrum and append- 
ages dusky. Body length 1.7-2; hind tibia .38-.45; hind tarsal II .13-.14; antenna .33. 
Alate Vivipara. Head and thorax blackish; abdomen greenish to blackish; slightly floc- 
culent; rostrum, cauda, anal plate, genital plate and appendages blackish. Body length 1.5- 
1.6; hind tibia .55-.70; hind tarsal II .15-.17; antenna .50-.55; fore wing 2.5-3; hamuli 2-3 in 
number. Rostrum attaining 2d coxa. 
Gall. Pale yellow or red. Composed mostly of swollen leaf base and flat but broadened 
petiole; exit hole a slit on underside between leaf and petiole. 
Collections. As winter host in petiole and leaf gall on Populus angustifolia 
and P. “balsamifera (?)” (probably P. candicans or deltoides since the loculities 
recorded are out of the habitat range of P. tacamahaca). Utah: Throughout 
