SUBFAMILY APHINAE 103 
However, the range of variation grades very close and indeed intergrading 
individuals occur in the Colorado collection so it is impossible to draw a sepa- 
rating line between the three so-called species. 
It appears likely that these three forms are only variations of P. macro- 
stachyae but biological investigaticns should be conducted to settle the matter. 
Genus Sipha Passerini 
Passerini, 1860:29; Baker, 1920a:35. ” 
Characters. Body flat and elongate, covered with long, stout spines. 
Frontal tubercles lacking. Antenna shorter than body; five-segmented, bearing 
hairs not longer than diameter of segments bearing them; secondary sensoria 
circular, large; unguis longer than half base of VI. Cornicle truncate, short, 
not longer than broad. Cauda knobbed; anal plate rounded, often hidden by 
terminal segment of abdomen. Living on leaves of grasses in wet places. 
Genotype (fixed by Passerini, 1860), Aphis glyceriae Kaltenbach. 
Key to Species of Sipha 
1. Body surface denticulate; unguis not shorter than base (p. 103) -........2...:.::ccceeeeeeeeeee- glyceriae 
PED OC YES IET a CORSITIOOCINW eee me et scat ey ee eee, ein ee EAST ee Sean ot te eee ee ee 2 
PUN UISEShOrcerst any DAS 6a. pie LO 3) mecke sence te fu ooa le ee swansea eee nega agropyronensis 
Wnsursmlonvgersthany bases (notatakenyin)t eet On))ss sere ecco create en eee eee tlava 
Sipha agropyronensis (Gillette) 
Chaitophorus agropyronensis Gillette, 1911a:442. 
Sipha agropyronensis, Gillette and Palmer, 1931:915. 
Alate Vivipara. Head and thorax brown to black; abdomen pale green with faint dusky 
dashes. Body length 1.6-1.9; hind tibia .6; hind tarsal II .20; antenna .65. Rostral IV+V 
broad in lateral aspects, slender obtuse in ventral aspect, .11 long, not attaining 3d coxa. Anal 
plate slightly emarginate. Body surface smooth. Hairs simple; on body rather heavy spine- 
like, numerous, .02-.05 long; on vertex, slightly heavier; on hind tibia rather fine, semierect 
.03-.05. Fore wing with media either once- or twice-branched. Other characters as described 
for genus. 
TSS ; 
Fig. 111. Sipha agropyronensis 
Apterous Summer Vivipara. Body 1.8 by .7; hind tibia .5; hind tarsal II .15; antenna 
.43-.49. Otherwise as in alate vivipara except that hairs are slightly heavier and longer. 
Ovipara. Apterous. Same as apterous vivipara except hind tibia proximal half to two- 
thirds of which is slightly swollen and bearing 10-12 large, often paired or double, sensoria. 
Collections. On upper surface of leaves of Agropyron sp. Colorado: Fort 
Collins, Boulder, and Denver. Apterous summer viviparae May 26 to Sept. 18, 
alate viviparae May 31 and July 23, oviparae Oct. 13; fairly common. 
Type. U.S.N.M. Paratypes, Colo. Agr. Exp. Sta. Collection. 
[Genotype Sipha glyceriae (Kaltenbach) ] 
Aphis glyceriae Kaltenbach, 1843:113. 
Sipha glyceriae, Hille Ris Lambers, 1934:32. . 
Apterous Summer Vivipara. Body elongate, egg-shaped flattened. Green with pale 
dorsal stripes and covered with short, stiff bristles and smoky denticles. (Cleared and mount- 
ed), body immaculate; appendages, cauda and tip of rostrum dusky; cornicle black. Body 
length 1.70; antenna five-segmented, .55 long; hind tibia .45-.50; hind tarsal II .13; rostrum 
hardly attaining 2d coxa. Hairs on body numerous. heavy, spinelike and .07-.11 long; on hind 
tibia fine, .06 long, rather numerous. 
Alate Vivipara. Head and thorax black; abdomen green, dorsum strewn with many 
