SUBFAMILY CALLIPHORINAE 277 
Acronesia aldrichia (Shannon), new combination 
Steringomyta aldrichia Shannon, Insecutor Inscitiae Menstruus 
11:112, 1923. (Type, male from Tennessee Pass, Colo., No. 
26163, in the U. S. National Museum.) 
Male. Head (pl. 6, A) height 11.1; width 13.1; length at an- 
tenna and vibrissa 7.4; eye height 7.6; bucca 0.43 eye height; 
frontale half as wide as parafrontale, dark brown to black; front 
black, with silvery pollen, at narrowest 0.10 head width, 0.20 at 
vertex and 0.30 at lunule, with scattered minute black hair out- 
side frontal row of bristles; frontal bristles 9 or 10, the rows 
following the margins of the frontale; parafaciale opposite lunule 
1.7 in width and as wide below, black, with silvery gray pollen; 
faciale and epistoma orange to orange brown; vibrissae set 2.6 
apart; first segment of antenna black, second orange brown 
apically, third 3.7 times as long as second, orange brown to 
brownish black; arista black with medium-length, black cilia; 
palpus orange, 4.3 in length; back of head not as rounded as in 
abina, black, with silvery pollen, with one or two rows of post- 
ocular cilia and with considerable scattered black hair. 
Thorax black, with thin silvery pollen, with a shining black 
middorsal longitudinal stripe between acrostichal rows and a 
narrower lateral longitudinal stripe laterad of each dorsocentral 
row; preacrostichal bristles three, strong, hindmost placed 1.2 
before suture; hindmost predorsocentral bristle placed 0.6 be- 
fore suture; sclerites at wing-base dark brown to black; squamal 
process with a few dark hairs; scutellum with under surface 
laterally with black hair, one discal bristle (sometimes two), 
and three lateral bristles (sometimes a long thin hairlike bristle 
between basal and intermediate ones). 
Legs black; middle femur with one anterior bristle near mid- 
dle; hind tibia usually with three posterodorsal bristles, one at 
basal fourth, one at basal third, and one at apical third. 
Wing hyaline, brownish; costal sections 2 to 6 in the propor- 
tion 83: 51:128: 47:10; bend of fourth vein acute, often leaving 
a short spur or fold; upper squamal lobe with rim and cilia 
brown; lower squamal lobe brown, the rim lighter in color. 
Abdomen with intermediate sternites of about equal length, 
otherwise like abina. 
Genital segments (pl. 26, E) as illustrated. 
Female. Head height 10.5; width 14.0; eye height 7.1; bucca 
0.49 eye height; length of antenna 7.5 and at vibrissa 8.4; front 
with nearly parallel margins, at vertex 0.38 of head width, 0.40 
at lunule; parafaciale 1.9 in width opposite lunule; distance be- 
