176 APHIDS OF THE ROCKY MOUNTAIN REGION 
abdomen and a large blotch on abdominal IV, V and VI or more; appendages, cornicle and 
cauda black. Body length 2-2.25; hind tibia .80; antenna 1-1.1; rostrum hairy, attaining or 
surpassing 3d coxa. Hind tibia somewhat swollen on proximal half which portion bears 6-20 
sensoria; otherwise as in alate vivipara. 
Alate Vivipara. Black throughout, dorsal patch evident even in cleared specimen. An- 
tenna, cornicle, cauda, and tibiae, except proximal portion, black. Body length 2; hind tibia 
-9-1; hind tarsal II .12; antenna 1.2, base of VI abruptly constricting to unguis, secondary 
sensoria oval, somewhat tuberculate; rostrum attaining between 2d and 3d coxae. Hairs 
pointed, rather numerous, drooping to semierect; .02-.03 long on antenna and hind tibia. 
Cornicle tapering, with flange, and with denticulate imbrications. Cauda short, hardly evident, 
much broader than long, rounded, with about 3 hairs on each side. Both alate and apterous 
viviparae, even as early as 2d instar, with hind tibia swollen on proximal half and bearing 
large circular sensoria on this portion. Fall alate vivipara may show little swelling and no 
more than 5 sensoria while spring and summer alatae may have as many as 18 sensoria on 
swollen portion. 
Ovipara. Apterous. (In alcohol), pale yellow. Body length 1.25; antenna .58-.66; hind 
tibia .52-.60, swollen along entire length and covered with sensoria. 
Male. Alate. Body length 1.40; antenna 1.40; hind tibia .70, not swollen and without 
sensoria. 
ie 
Fe ae RISD 
19-23 Sen. 
Fig. 201. Aphis sensoriata 
Collections. On leaves and twigs of Amelanchier sp. Colorado: Log Cabin 
(west of Livermore), Laramie-Poudre Tunnel, Cameron Pass and Hesperus 
(all above altitude of 8000 ft.). Fundatrices May 26, apterous viviparae July 12 
to Aug. 25, alate viviparae July 27 to Oct. 1, sexuales Oct. 1; rather rare. 
Type. U.S.N.M., No. 41927. Paratypes, Colo. Agr. Exp. Sta. Collection. 
Chief Distinguishing Characters. Sensoria present on proximal somewhat 
swollen part of hind tibia of alate and apterous viviparae even in nymph, short 
broad cauda, long rostral IV-+-V (.14-.17), denticulate imbrications on cornicle, 
numerous sensoria on antenna of alate vivipara and their occasional presence 
in aptera and considerably swollen hind tibia of ovipara rather thickly covered 
with sensoria, short cornicle (.12-.14, hardly longer than hind tarsal II) and 
short unguis (hardly longer than two-thirds of III). 
Aphis setariae (Thomas) 
The Rusty Plum Aphid 
Siphonophora setariae Thomas, 1877:5 
Aphis setariae, Oestlund, 1887:67; Gillette and Taylor, 1908a:41; Williams, 1910:57; 
Gillette and Palmer, 1932b: 444. 
Hysteroneura setariae, Cutright, 1925:197, 
Fundatrix. Color and measurements same as summer aptera except sometimes III and IV 
coalesced. 
Apterous Summer Vivipara. Dark chocolate-brown; shining; cauda, antennal III and IV, 
and tibiae except tips white; cornicle black; rostrum and anal and genital plates dark. Body 
length 1.4-2.3; hind tibia .80-1.1; hind tarsal II .11-.13; antenna 1.4-1.8, III and IV often 
coalesced in fall aptera, possible sexupara; rostral IV-+V broad, attaining or surpassing 2d 
coxa. 
