204 
IOWA ACADEMY OF SCIENCES. 
Color: Soiled white to light fuscous above; tip of vertex ivory white; 
triangle with a black margin, line near the margin before the ocelli; rec- 
tangular spot on disk, an oblique spot at base of vertex, as in D. indatus 
well marked, brown. Pronotum soiled white with faint indications of 
stripes; elytra sub hyaline, soiled yellowish-white, oblique band reduced to 
two spots, one on the clavus near the pronotum, the other between the first 
and second sectors unequally divided by the white cross nervure; apical 
and reflexed veinlets broadly white, darkly lined before as is also the outer 
apical margin; tergum broadly black at base, lined near tip; outer pair of 
lines approximate behind. Below upper half of face sharply black, light 
arcs more or less distinct; lower half sharply white; venter fuscous. 
Genitalia: Ultimate ventral segment of female about half as long as 
broad, margin roundingly produced in the center, notched. Disk light, 
produced part black, pygofers broad, short, brown, maculate with white. 
Male valve broad, obtusely pointed; plates broad at base, concavely, attenu- 
ately pointed, three times the length of the valve, equaling pygofers. 
Described from numerous specimens. 
Larvae resembling those of albidus in form and sayi in color, but with 
more definite stripes. Upper half of the face black. 
Vertex: Sides acutely angled, point obtusely rounded; body slender, 
tapering, last abdominal segment, long, narrow. Color above, striped with 
olive and white, a narrow median white line from tip of vertex to the tip of 
abdomen slightly expanded on the last segment, a slightly wider light line 
margining the vertex next the eye on either side and running to the pos- 
terior margin of the penultimate segment of the abdomen; a narrow white 
margin on either side from behind the eyes to the last abdominal segment 
The pupae have a small round spot in the outer light line near the anter- 
ior margin of the thorax and a larger oblique mark near the posterior 
margin of the wing-pads; base of both rows of hairs on the abdomen 
with small round white spots. Below: Face, upper half black, lower half 
sharply white, as in adult, the dark line continuing along the fermora and 
connecting with them as in abidus larvae. 
This species and the three following strongly resemble each 
other. They are most accurately separated by the struct are 
of the genitalia, which have proved to be very constant in the 
hundreds of specimens studied, as in fact they have for the 
whole genus, though tested by the study of nearly 5,000 speci- 
mens. It has been c elected in abundance at Ames this season, 
and one Colorado example received from Professor Gillette. 
It was taken for the first lime, June 3rd, when it occurred as 
full-grown larvse and adult males. By the middle of June the 
larvae had disappeared and the adults were numerous, continu- 
ing so well into July. Small larvae were found the third week 
in July, and from then on they were numerous until the second 
week in August, when they had become full grown and begun 
to disappear. The adults appeared by the end of the first week 
in August, becomiog abundant by the middle and continuing to 
