230 ' DIPTERA. 
Big. (Ann. Soc. Ent. Fr. 1888, p. 265. no. 59); only the scutellum does not appear 
to be rufous, but cinereous (this may, however, be explained by the less fresh -con- 
dition of M. Bigot’s specimen), the ground-colour being indeed rufous, but thickly 
covered by a cinereous tomentum. Bigot gives as localities for R. major Mexico and 
Washington Territory. 
‘The females generally are smaller in size, the largest being no more than 11 millim. 
In some of them the wings are rather darker in tint, and such specimens bear a striking 
resemblance to the typical example of Dexiosoma fumipennis, Big. (1. c. p. 270. no. 84), 
which, however, is by no means a Dexiosoma. 
7. Rhynchodexia scutellata. sp.n., s 2. 
Thorax blackish ; abdomen rufous, with a black dorsal band; antenne, palpi, scutellum, and tibie rufous ; 
pulvilli pale yellow. 
Length 10°5-12 millim. 
Head whitish; cheeks and oral margin with rufous reflections, the cheeks bare; front somewhat prominent 
and flattened, in the male much narrowed behind, in the female broader than the eyes; frontal band 
brownish-black, immediately before the root of the antenne rufous; face slightly inclined, in the middle 
distinctly carinated; vibrissal swellings curved inwards; oral margin not prominent. Antenne rufous; 
second joint with some long bristles; third joint slender, fully twice as long as the second, infuscated 
towards the tip; arista thickened at the base, moderately long-plumose. Proboscis as long as the 
head, brown, with the terminal lips rufous; palpi rufous, cylindrical, long-haired. Thorax black; in 
the male the shoulders and two small spots on the front margin whitish; in the female the thoracic 
dorsum, before the transverse suture, cinereous, with three black stripes; scutellum rufous. Abdomen 
of the male conical, yellowish-rufous, transparent, with a well-defined black dorsal band and some 
white reflections on the sides; seen laterally the anal segment is truncate; many discal and marginal 
macrochete are present;—in the female the abdomen is ovate, less transparent, the black dorsal 
band not so sharply delineated, the anus pointed, and the macrochzte less numerous. Legs black; 
tibie dark rufous; femora with regularly arranged bristles; middle and hind tibie with some scattered 
bristles ; foot-claws and pulvilli elongate in the male, the pulvilli pale yellow. Tegule whitish, with a 
yellow margin. Wings greyish; small cross-vein on or a little before the middle of the discal cell ; 
apical cross-vein slightly concave ; posterior cross-vein curved. 
Hab. Mexico, Ciudad in Durango 8100 feet (Forrer). 
Two male and two female specimens. 
8. Rhynchodexia rubricornis, sp. n., ¢ ¢. 
Thorax black, anteriorly grey with black stripes; abdomen rufous, with a black dorsal band; antenne and 
palpi rufous, the antenne black towards the tip; legs black; pulvilli grey. 
Length 11 millim. 
Nearly allied to R, scutellata and agreeing with it, except in the following respects:—The front is a little 
more concave ; the antenne are shorter, the third joint broader, black on the apical two-thirds; the 
arista has longer hairs ; the vibrissal swellings are parallel ; the thoracic dorsum is, in both sexes, before 
the transverse suture covered by a grey tomentum, in which threo median and two lateral black stripes 
are conspicuous, the median stripes linear and close together; the rufous portions of the abdomen are 
scarcely transparent and the limits of the black dorsal band obsolete, even in the male; the pulvilli are 
dark grey. 
Hab. Mexico, Northern Sonora (JJorrison), La Venta 300 feet, Amula 6000 feet, 
