Diptera 
293 
11. Cell R 2 nearly or quite as long as its petiole, or 
otherwise distinct. 
m. Femora with erect outstanding scales; occiput 
broad and exposed. Large species. P. ciliata. 
P. howardi.Psorophora R. D. 
mm. Femora without erect scales. 
n. Clypeus bearing several scales or hairs, scutel- 
lum with broad scales only; back of head 
with broad scales; scales along the sides of the 
mesonotum narrow; some or the claws 
toothed; thorax marked with a pair of 
silvery scaled curved stripes; legs black 
with white bands at the bases of some of the 
segments (fig. 134). Yellow Fever mosquito 
.Aedes ( = Stegomyia) calopus. 
nn. With another combination of characters. 
Numerous species of mosquitoes belonging 
to several closely related genera, widely 
distributed over the country'. ( Culex , Aedes, 
Ochlerotatus, etc.). Culex in the wide sense, 
ii. Metanotum with setae. Wyeomyia (found in the United 
States); and related tropic genera. 
bb. Antennae composed of three segments with a differentiated style or bristle; 
third segment sometimes complex or annulate, in which case the empo- 
dium is usually developed like the pulvilli, i.e., pad-like (fig. 161 g). 
c. Empodium developed pad-like (pulvilliform) i.e., three nearly equal 
membranous appendages on the underside of the claws (fig. i6ig). 
d. Squamae, head, and eyes large; occiput flattened or concave; third 
segment of the antennae with four to eight annuli or segments, 
proboscis adapted for piercing; body with fine hairs, never with 
bristles; middle tibia with two spurs; wing venation as figured 
(fig. i63f); marginal vein encompasses the entire wing. Horse 
flies, greenheads, deer flies, gad flies. Tabanid.®* 
e. Hind tibia with spurs at tip; ocelli usually present (PANGONIN.*) 
f. Third joint of the antennae with seven or eight segments; probo- 
cis usually prolonged. 
g. Each section the the third antennal segment branched. Central 
American species, P. festce . Pityocera G. T. 
gg. Sections of the third antennal segment not branched. 
h. Upper corner of the eyes in the female terminating in an acute 
angle; wings of both sexes dark anteriorly. G. chrysocoma, 
a species from the eastern states . Goniops Aid. 
hh. Upper comer of the eye in the female not so terminating; 
wings nearly uniform in color, or hyaline, 
i. Proboscis scarcely extending beyond the palpi; front of the 
female wide; much wider below than above. S. W. 
States . Apatolestes Will. 
*This table to the North American genera of the Tabanidffi is adapted from one given by 
M iss Ricardo. 
