326 JOURNAL OF ECONOMIC ENTOMOLOGY (Vol. 4 



Antenna dusky to blackish, the two basal segments also dusky, l)Ut paler than the 

 others; VI filament longest, it being about twice the length of the next longest seg- 

 ment (segment III), IV fully a third shorter than III, IV and V subequal, VI base 

 about 2-5 the length of V or 1-8 the length of VI filament, total lengths about 1 1-2 

 times that of the body; III with 23-33 (usually 27 or 28) small but conspicuous, 

 circular, irregularly placed sensoria, IV with 13-18, V with 1-4, usually in a row 

 and the usual larger one at distal end, VI base with a large one surrounded by a 

 number of minute ones at distal end. (PI. 10, fig. 2.) Eyes red. Beak not reaching 

 to coxse of the second pair of legs. Wings with veins dark brown and distinct, third 

 discoidal branching slightly nearer to the apex than to where the second branches. 

 (PI. 10, fig. 1.) Legs pale yellowish, excepting the joints, which are browm.sh, and 

 the tarsi, which are black. Cornicles reaching beyond tip of abdomen, very slender, 

 the basal two-thirds swollen, the distal third pale yellowish to greenish yellow 

 and dusky at tips. (PI. 10, fig. 4.) Style moderately long and slender, about a 

 third the length of cornicles. (PI. 10, fig. 5.) 



Measurements. — Length of body, 1.8 mm.; width, 0.72 mm.; length of forewing, 

 3.0 mm.; width 1.25 mm.; antenna, I, 0.10; II, 0.065; III, 0.38-0.44, avg. 0.42; IV, 

 0.27-0.36, avg. 0.33; V, 0.245-0.31, avg. 0.28; VI, base, 0.09; VI, filament, 0.82-0.93, 

 avg. 0.86; avg. total, 2.145 mm.; cornicles, avg. 0.42 mm.; style, avg. 0.145 mm.; 

 hind tarsus, avg. 0.11 mm. 



Wingless viviparous female. — Entire body pale yellow. Head and first antennal 

 segment bearing several whitish capitate hairs. Antennae whitish, about as long 

 as body, relative lengths of segments as in winged viviparous female. Eyes dark 

 red. Beak not reaching beyond coxse of second pair of legs. Legs whitish. Corni- 

 cles and style whitish, otherwise as in winged. 



Measurements: — Average, in mm. Length of body, 2.3; width, 1.07; antenna, 

 I, 0.095; II, 0.06; III, 0.45; IV, 0.35; V, 0.29; VI, base, 0.085; VI, filament, 0.85; 

 cornicles, 0.67; style, 0.19. 



Winged male. — In relative measurements similar to the winged viviparous, diflfer- 

 ing from it as follows: head and thorax blackish, abdomen pale yellowish, with a 

 slight faint orange tint, the longitudinal median dorsal red line which is so conspic- 

 uous in the pupal stage is faintly visible, and on each side of the median, extending 

 longitudinally, are short dusky transverse markings, one or two of which are some- 

 times connected at the median line, thus forming single transverse bars on the respect- 

 ive abdominal segments. Entire body covered with a fine pulverulence. Antennae 

 black, and with circular sensoria irregularly placed as follows: III, 33-39; IV, 

 20-31 ; V, 8-13. Femur dusky to blackish, being paler at the base, tibia pale except- 

 ing black distal end, and tarsus black. Cornicles and style dusky and a black spot 

 at the base of each cornicle. 



The conspicuously marked immature male is at once distinguished 

 from the pale yellowish young of the viviparous generations. It is 

 characterized by a bright reddish longitudinal median dorsal line 

 on a pale yellowish background, and extends the entire leng^th of the 

 body. In the adult pupa the line is not such a bright red, and the 

 abdomen is more of a pale orange color. 



*Macrosiphum, asclepiadis Cowen: Bull. Col. Agr. Expt. Station 

 No. 31, Tech. Ser. No. 1, (1895), p. 123. A rather common species 

 in Illinois, on Asdepias sp. This may have been one of the species 



