566 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 118 
Except for the structure of the male hind leg and terminalia, all 
species of Acantholeria appear to be very similar to one another. 
Slight differences in coloration may occur among the species, but 
apparently not enough to be a sound basis fora key. At present, I am 
able to distinguish with certainty only male specimens. A general 
description of the flies of this genus follows. 
MALE AND FEMALE.—Lower back of head yellow, blending into the 
grayish vertex, ocellar triangle, and frontal plates; antennae yellowish 
orange to brownish, aristae dark brown, minutely pubescent ; remainder 
of head yellow; anterior fronto-orbital bristle usually less than one-half 
the height of the posterior fronto-orbital bristle; oral vibrissae strong, 
a single row of buccal setae. 
Thorax grayish yellow to grayish brown, often becoming quite 
yellowed at edges of sclerites and on the scutellum; dorsocentrals 
1+ 3; prescutellar bristles present (but weak); humeral bristle present; 
2 notopleural, 3 supra-alar, and 2 pairs of lateral scutellar bristles; 
3 rows (often irregular) of setae between the dorsocentral bristles; 
propleural bristle strong, mesopleura bare except for several small 
setae near the propleural; no prosternal bristles; 1 strong sternopleural 
with several small setae anterior to it and longer hairs ventrally 
between the coxae; remainder of pleura bare. 
Legs yellow to yellowish or reddish orange, sometimes becoming 
darker distally; all tibiae with dorsal preapical bristle; middle tibiae 
with several bristles ventrally; hind leg shows great diversity in the 
males of the individual species. 
Wings hyaline, no distinct infuscations, costal spines well developed. 
Abdomen gray to grayish brown; dorsum with scattered setae and 
a row of bristles at the posterior margins of segments 2-5. 
Lenetu.—5.0—-7.0 mm. 
Key to the Species of Acantholeria (Males only) 
1. Hind tibia with a distinct knob posteroventrally, the knob about twice as long 
as wide and projecting slightly toward the distal end of the tibia. 
abnormalis Garrett 
Hind tibia with at most a bumplike swelling less than twice as long as wide. . 2 
2. Hind femur with a row of 12 to 20 spines; the tibia with a slight swelling near 
the middle pate ary i ene Geb spectre . . moscowa Garrett 
Hind femur with a row oe Uf me ‘12 ees tibial swelling present or absent . . 3 
3. Hind femur with spines arising from a slightly raised ridge; tibia with bumplike 
swelling. ... . . . armipes (Loew) 
Hind femur with Spine not arieitie feral a Famed mide: tibia with no distinct 
swelling. 2. 5% shiv ele Ae the Rae ORE Me A <2 Seimerariag(toens 
