SUBFAMILY CALLIPHORINAE 245 
black; hindmost preacrostichal and predorsocentral bristles 2.6 
and 1.2, respectively, before suture; postacrostichal bristles two. 
Legs usually black but sometimes brownish on femora and 
tibiae. 
Wing hyaline, faintly brownish anteriorly and toward base; 
basicosta dark brown to black; subcostal sclerite orange brown 
basally, darker brown apically, with fine decumbent brown pile; 
costal sections 2 to 6 in the proportion 73 :50 :90 :39 :9; second and 
third sections of fourth vein in proportion 74:67; third vein 
setulose nearly one-half the distance to the cross vein; squamal 
lobes white at base, the lower lobe brown apically. 
Abdomen colored like thorax, first segment dark purplish; 
second segment with only a suggestion of marginal row of 
bristles; third segment with marginal row of strong bristles; 
fourth segment with scattered erect bristles. 
Genital segments brown to black, slightly greenish dorsally, 
with scattered erect black hairs. Anatomical features (pl. 24, I) 
as illustrated. 
Female. Head width 15.5; height 12.0; eye height 8.6; length 
at antenna and at vibrissa 6.4; bucca 0.33 of eye height; frontale 
narrowed anteriorly, orange red to brown; frontal rows of 
bristles consisting of about seven each, the rows strongly diver- 
gent anteriorly; vertex black, slightly silvery; parafrontale at 
narrowest 0.29 of head width, only slightly wider at vertex and 
0.32 at lunule, silvery, with a row of minute setulae near eye 
which extend anteriorly to nearly opposite foremost frontal 
bristle; parafaciale opposite lunule 1.7 in width; vibrissae set 
3.0 apart; antenna with third segment 4.7 times as long as 
second; palpus 3.9 in length. Wing with costal sections 2 to 6 
in the proportion 81:57:112:45:11; both upper and lower 
squamal lobes white. Otherwise similar to male except for nor- 
mal sexual differences. 
Length. 6-9 mm. 
Distribution. Nearectic and Neotropical: As far south as 
Brazil and as far north as Arizona, New Mexico, and Texas. 
Biology, habits, and immature stages. Ineubation period: 
Melvin (1934) found that incubation of eggs of this species did 
not occur at temperatures below 75° F., and at this temperature 
14.03 hours were required for the eggs to hatch. No hatching 
occurred at temperatures higher than 99° F., and at this tem- 
perature 8.12 hours were necessary for complete incubation. 
The optimum temperature for the incubation appeared to be 
at about 94° F., at which temperature development y was com- 
pleted in 7.77 hous: 
