128 PROCEEDINGS OF THE NATIONAL MUSEUM, VoL. 62. 
to the genus Psilocephala. Owing to the poor condition of the types 
two of the species given below could not be assigned to the genus 
Thereva with certainty. 
THEREVA VARIA Walker. 
1848. Thereva varia WALKER, List Dipt. Brit. Mus., vol. 1, p. 221. 
The original description is as follows: 
Female.—Fusca, subtus cinerea abdomine fulvo facsiis canis, antennis canis apicis 
nigris, pedibus fulvis, femorum tibiarum tarsorumque apicibus nigris, alis subcinereis. 
Head black and clothed with black hairs, hoary with a tawny tinge in front, 
thickly clothed with white hairs beneath; feelers hoary with a very slight tawny 
tinge, black at the tips; mouth black, and clothed with black hairs; chest brown, 
with yellow hairs; breast gray, with hairs of the same color; abdomen very dark 
tawny, covered with a white bloom, and clothed with white hairs; fore borders of the 
segments hoary; underside gray, with a tawny spot on each side of every segment; 
legs tawny, clothed sparingly with black bristles; tips of the thighs, of the shanks, 
and of the joints of the feet black; wings slightly gray, darker and with a brownish 
tinge along the fore border; brands brown; veins piceous; cross veins bordered with 
brown; poisers tawny, with piceous knobs. Length of the body 3 lines, of the wings 
6 lines. 
a. Florida. Presented by E. Doubleday, Esq. 
Major Austin adds the following notes from the type in the British 
Museum: 
Antennae and one front leg missing, type otherwise in fairly good condition; sides 
of face hairy; fourth posterior cell widely open. Owing to the absence of the an- 
tennae, I am unable to say whether this species is a true Thereva in the present-day 
sense. 
THEREVA NERVOSA Walker. 
1848. Thereva nervosa WALKER, List Brit. Mus., vol. 1, p. 223. 
Walker’s original description is as follows: 
Male.—Niger, abdomine piceo basi subtus ferrugineo, antennis pedibusque fulvis, 
femoribus cinereis, alis subcinereis, venis fusco marginatis. 
Head and chest black; head clothed with black hairs above, and more thickly 
with white hairs beneath; feelers tawny; first joint very long and thick, and clothed 
with long black hairs; breast thinly clothed with long white hairs; abdomen piceous, 
ferruginous beneath toward the base; legs thinly clothed with black bristles and 
short black hairs; hips and thighs gray; shanks and feet tawny; tips of the feet joints 
piceous; wings slightly gray, especially at the tips and along the fore borders; brands 
and veins brown; cross veins bordered with the same color; poisers tawny, with 
brown knobs. Length of the body 4 lines, of the wings 8 lines. 
a. Georgia. From Mr. Abbot’s collection. 
Major Austin gives the following notes from the type in the British 
Museum: 
Type in very bad condition, greasy and entirely discolored; only three legs, al} 
without terminal joints of tarsi; eyes narrowly separated above. I am unable to say 
to what genus this species should be assigned. 
