226 
The Ohio Naturalist 
[Vol. V, No. 2, 
Chrysops surdus Osten Sacken. Somewhat like proclivis but 
smaller. The facial callosities are black on both sides of the 
suture leaving a narrow yellow stripe on the middle of the face. 
The male is darker than the female and much like the male of 
proclivis in general appearance. However, the same characters 
which separate the females may be used in regard to the males. 
Chrysops virgulatus Bellardi. Although this species has not 
been taken in the United States so far as I know, it seems best to 
include it in treating our species with the first antennal segment 
enlarged. Female 6 to 9 millimeters. First two antennal seg- 
ments decidedly swollen, .shining brownish, darkest above; third 
segment with basal annulus decidedly yellow, remainder black, 
slightly longer than the second, but not so long as the third. 
Ocellar area black, widely separated from the eye on either side ; 
legs yellow with the exception of the knees, apical part of front 
tibiae and their tarsi and distal parts of other tarsi black or 
brown. Wings with costal margin and cross-bands black, apical 
spot rather wide, entirely filling out the marginal cell, the apex 
of first submarginal and extending into the second submarginal. 
The cross-band includes more than half of the first submarginal 
cell and about half of the first posterior, not quite half of the 
second posterior, and more than half of the third posterior, all of 
the fourth posterior and discal, basal half or more of fifth posterior 
and apexes of anal and first and second basal cells; basal two- 
thirds of first basal and one-third of second basal also black; a 
whitish area invades the hyaline areas on the outer and inner 
margins of the cross-band. Abdomen black and yellow, black as 
follows: An oblong patch beneath the scutellum, two or four 
usually connected spots on anterior part of second segment, and 
four oblong spots on each of the remaining segments separated 
longitudinally by yellow. The black on all the segments may be 
connected anteriorlv and the last two segments may be alto- 
gether black. Venter yellow with a wide median black stripe 
and a narrower one on each side. 
The male is decidedlv darker than the female, the hyaline 
triangle of the wings is the same in both sexes, but the hyaline 
in the basal and anal cells consists of a spot in each, and taken 
together form a crescent, the spot in the anal cell being located 
nearer the wing base; the whole axillary cell is smoky. 
Distinguished from related species by the short third antennal 
segment and the bright yellow basal annulus of the same. Sev- 
eral males and females taken at Guadalajara, Mexico, by Jesse 
McClendon in June and July, 1903. The synonomy is by Wil- 
liston and I believe it should be adopted. 
