Jp uC 
Ayo 
164 DIPTERA. 
thorax, the former with the frontal band black and the latter with more distinct black 
stripes, the pilosity of the eyes very inconspicuous (only visible under a strong lens), 
and the front borders of the abdominal segments with broader white reflections. In 
general, it has more the aspect of D. albomicans ; but, owing to the absence of discal 
macrocheete, it cannot be identified with that species. 
15. Didyma fuliginipennis, sp. n., 3. 
Head whitish ; thorax cinereous, with black stripes ; abdomen black, with white front borders to the segments ; 
no discal macrochete; antenne, palpi, and legs black; wings brownish. 
Length 4:5 millim. 
Front cinereous, with whitish reflections, narrowed behind and there as broad as the eyes ; frontal band black, 
as broad as the lateral portions; frontal bristles somewhat irregular, but descending on each side in a 
single row to beneath the second antennal joint; face and cheeks whitish; eyes densely clothed with a 
weak pile ; vibrisse inserted at the oral margin. Antenne shorter than the face ; third joint five times 
as long as the second; arista thickened to the proximal third. Proboscis and palpi black. Thorax 
cinereous, with four black stripes, the intermediate stripes linear and more distinct ; scutellum black. 
Abdomen elliptical, shining black ; the second and following segments with white front borders, which, 
at the middle, are interrupted by a black dorsal stripe ; long macrochsete are on the hind margins of the 
second and third segments; on the anal segment the macrochextx are shorter, but more numerous. 
Middle tibisee with some long bristles; hind tibie outwardly with several bristles of unequal length ; 
foot-claws and pulvilli a little elongate, the pulvilli yellowish-grey. Tegule whitish. Wings with a 
brownish-grey tint, more obscure towards the costa; small cross-vein distinctly before the middle of the 
discal cell; apical cross-vein straight ; posterior cross-vein slightly curved. 
Hab. Mexico, Omilteme in Guerrero 8000 feet (H. H. Smith). 
A single male specimen. 
16. Didyma validinervis, sp.n., 3 °. 
Blackish ; thorax grey, with four black stripes ; abdomen with whitish reflections and white front margins to 
the segments; no discal macrochete ; wings with strong veins; apical cross-vein concave. 
o Length 6-7 millim. 
Head grey, with whitish reflections ; front narrowed behind and there narrower than the eyes, in the female 
a little broader; frontal band black, as broad as the lateral portions ; frontal bristles forming on each 
side a nearly continuous row with the bristles on the facial ridges; eyes thinly pilose ; beard white. 
Antenne black, a little shorter than the face ; third joint five times as long as the second ; arista thickened 
to the proximal half. Proboscis and palpi_black, the palpi filiform. Thorax greyish, with four equal 
broad, black stripes, the outer stripes interrupted at the transverse suture ; scutellum greyish-black. 
Abdomen elliptical in the male, ovate and more flattened in the female ; first segment black, laterally 
with a whitish reflection ; the following segments black, with narrow white front margins and some 
whitish reflecting spots; on the hind margins of the segments are long macrochete. Legs black ; front 
tibiee outwardly with a bristle; middle tibiee with some long bristles; hind tibiz with several scattered 
bristles. Tegule yellowish-white. Wings with a brownish-grey tint, more intense towards the base 
and costa; the veins strong and somewhat infuscated ; small cross-vein on the middle of the discal cell ; 
curvature of the fourth vein rectangular; apical cross-vein distinctly concave; the second section of the 
fourth vein (between the small and posterior cross-veins) slightly bent upwards; posterior cross-vein 
curved. 
Hab. Mexico, Xucumanatlan, Omilteme, and Sierra de las Aguas Escondidas, all 
in Guerrero, 7000 to 9500 feet (H. H. Smith). 
Several specimens of each sex. 
