344 DIPTERA. 
inferior part of the cheeks linear. Antenne yellow, inserted above the median line of the eyes; second 
joint with a bristle ; third joint double as long as the second, thin and slender, slightly infuscate towards 
the tip; arista pubescent. Proboscis black; palpi yellow, small, filiform. Thorax cinereous, with 
indistinct brown stripes; scutellum brown; metanotum grey. Abdomen cinereous, elliptical, pointed 
towards the tip; first three segments with a brown dorsal stripe and two large brown spots; weak 
macrochete on the third and anal segments. Legs yellowish-rufous, the tarsi slightly infuscate, the 
middle and hind femora black at the tip; hind tibia with three long bristles. Tegule and halteres 
yellow. Wings with a yellowish-grey tinge ; small cross-vein beyond the end of the first vein and beyond 
the middle of the discal cell; third and fourth veins slightly curved and parallel; terminal section of the 
fourth vein double as long as the penultimate section ; posterior cross-vein straight and nearly 
perpendicular, 
Hab. Mexico, Atoyac in Vera Cruz (H. H. Smith). 
A single female specimen. 
3. Ceenosia oscillans, sp. n., 3. 
Grey ; base of the abdomen yellow and transparent ; palpi, base of the third antennal joint, and legs yellowish- 
rufous. 
Length 5 millim, 
Front as broad as the eyes, greyish-cinereous; face and cheeks white; inferior part of the cheeks linear. 
Antenne inserted above the median line of the eyes; basal joints black, the second white at the tip; 
third joint three times as long as the second, yellowish-rufous at the base, blackish-brown towards the 
apex ; arista pubescent, its basal joint conspicuous. Proboscis rufous-brown, the tip black ; palpi yellow, 
small, slightly enlarged towards the apex. Thorax and scutellum greyish-cinereous, the prothorax with the 
sides above the front coxe whitish; thoracic dorsum with indistinct brown stripes; the macrochete 
arising from black points. Abdomen subcylindrical, yellow, transparent, gradually becoming grey 
and opaque on the last segments ; indistinct brownish spots at the sides of the median segments; male 
genitalia yellowish-rufous; long macrochete present at the sides and on the anal segment. Legs 
yellowish-rufous, the tarsi brown ; foot-claws and pulvilli rather short. Tegule and halteres yellowish. 
Wings greyish-hyaline ; small cross-vein beyond the end of the first vein and a little beyond the middle 
of the discal cell; third and fourth veins slightly curved and parallel; terminal section of the fourth 
vein longer than the penultimate section (3:2); posterior cross-vein straight, nearly perpendicular. | 
Hab. Mexico, Amula in Guerrero 6000 feet (H. H. Smith). 
A single female specimen. 
4, Cenosia macrocera, sp.n. ¢ 2. (Tab. VIII. figg. 17, ¢; 17a, head in 
profile, 3.) 
Cinereous; abdomen with yellow base and brown dorsal spots, blackish towards the apex; legs yellowish- 
rufous; antenne and palpi black. 
Length 4-5 millim. 
Front as broad as the eyes, grey, with blackish stripes; face and cheeks whitish, the face slightly retracted, 
the cheeks narrow, their inferior part under the eyes linear ; occiput grey, somewhat convex. Antenne 
black, inserted much above the median line of the eyes; second joint white at the tip; third joint four 
times as long as the second, reaching to near the vibrisse; arista long, microscopically pubescent. 
Proboscis and palpi black ; the palpi small, filiform. Thorax and scutellum greyish-cinereous ; thoracic 
dorsum with indistinct brown stripes; metanotum grey. Abdomen of the male cylindrical, first and 
second segments yellow and slightly transparent, with a large triangular brown spot, the third and anal 
segments blackish, with some grey tomentum; that of the female elliptical, pointed towards the tip, 
yellow, with a dorsal stripe and the hind borders of the segments blackish ; often the ground-colour of 
the terminal segments is more greyish ; some macrochexte present at the sides of the segments and also 
