362 APHIDS OF THE ROCKY MOUNTAIN REGION 
Male. Apterous. Body length .78; antenna four-segmented, .11, I .026, II .021, III+IV 
+V (coalesced) .017 with permanent sensorium near distal end, VI .052 with permanent sen- 
sorium at base of unguis. Legs somewhat rudimentary; tarsi shorter than the diameter of 
tibia, cone-shaped. Rostrum lacking. 
Description of sexuales taken from original description by Maxson (op. cit.). 
Gall. Pale greenish yellow. Composed mostly of swelling on upperside of leaf base 
with petiole broadened and somewhat twisted; orifice consisting of a slit on underside be- 
tween petiole and leaf. Gall may be either globular or with more or less transverse indenta- 
tion as shown in figure. 
Collections. In twisted petiole and leaf galls on Populus angustifolia and P. 
tacamahaca (There appears to be no alternate host since the alate viviparae 
leaving the gall as soon as it opens are already sexuparae and must deposit the 
sexuales on the winter host.) Colorado: Buckhorn Creek (near Masonville), at 
Redfeather, Horseshoe Park (in Rocky Mountain National Park), Colorado 
Springs and Walden. Fundatrices July 4 to Sept. 23, apterous summer viviparae 
July 12 to Sept. 23, alate viviparae (sexuparae) Aug. 18 to Sept. 23, sexuales 
Aug. 10 (born from alatae which were imprisoned); rather rare. The fundatrix 
and apterous viviparae (very few) are found in the galls with alate sexuparae. 
Type. U.S.N.M., No. 50065. Paratypes, Maxson Collection. 
This species is peculiar in the presence of a few apterous fundatrigeniae in 
the gall before the appearance of alatae and in the small size of both fundatrix 
and apterous fundatrigeniae. Whether the alatae are produced by the fundatrix 
or by the apterous fundatrigeniae or by both is not known. It is peculiar also 
in the development of sexuparae, apparently the only alate generation, in the 
same gall with the fundatrix, which situation indicates the lack of an alternate 
host. 
Pemphigus nortonii Maxson 
-Pemphigus nortoni Maxson, 1934:36; Gillette and Paimer, 1934:225. 
Fundatrix. (Mounted in balsam), pale with appendages pale brown. Body length 2.5- 
2.6; across eyes .45; hind tibia .47-.50; hind tarsal II .14; antenna .35-.40; rostral IV+V .10, 
attaining 2d coxa. Wax glands well developed, present on thorax and abdomen, each sur- 
rounded by a distinct chitinous ring. 
Furidgtrix 
4-16) ~~ (13-.14) 
Alate ee (sen. 3-6) Gadd 3-8) (sen. ?-//) 
oe See con FICO IAN CIRIBY (17d 025 
Fig. 435. Pemphigus nortonii 
Alate Vivipara. Fundatrigenia. Head and thorax blackish; abdomen yellow-green to 
bluish; powdery; appendages dusky. Body length 1.53-1.84; fore wing 2.3; hamuli 2 in num- 
ber; hind tibia .60-.73; hind tarsal II .16-.17; antenna .80-.83; rostral IV+V .09, attaining 1st 
and 2d coxae. 
Gall. Pale yellowish green. In swollen leaf base twisted on flattened and broadened 
petiole base; exit hole small, round orifice on underside between leaf and petiole. Size 20 
mm in diameter. 
Collections. On Populus sargenti in twisted petiole and leaf galls, indistin- 
guishable from galls of P. populi-caulis. Colorado: Longmont, Dent and Fort 
Collins. Wyoming: Wheatland. Fundatrices and alate viviparae (fundatrigen- 
iae) July 2 to Sept. 21; not very common. 
Type. U.S.N.M., No. 50064. Paratypes, Maxson Collection. 
Chief Distinguishing Characters. Character of gall (compased largely of 
enlarged leaf and with exit hole, a small round opening on underside between 
leaf and petiole), length of antenna (about half body length in alate vivipara 
and slightly exceeding twice distance across eyes and III not shorter than .23, 
in fundatrix III not shorter than .14) and number of secondary sensoria on VI 
(at least 7). 
