PSILA.—CHYLIZA. 361 
with spurs. Auxiliary vein at first united with the first vein, but separated from it 
towards the end, and indistinctly running to the costal vein, which is often interrupted 
at that place; the inferior two basal cells are rather large. 
The Central-American collections contain representatives of two genera, each with a 
single species. 
Face receding ; third basal cell as long as the second . . . . . . . . . ).) ) Posila. 
Face nearly perpendicular; third basal cell shorter than the second . . . . . . . Chyliza. 
PSILA. 
Psila, Meigen, Illig. Magaz. il. p. 278 (1803). 
1. Psila exigua, sp. n., ¢. 
Shining black; head, antenne, and legs yellow; wings hyaline. 
Length 3 millim. 
Head yellowish-rufous, shining ; ocellar knob and a double spot on the occiput brown; the minute bristles on 
the vertex yellow. Antenne, including the arista, proboscis, and palpi yellow. Thorax, scutellum, and 
abdomen shining black; thoracic dorsum with a short, white pilosity. Legs yellow. Halteres whitish. 
Wings much longer than the abdomen, hyaline, with yellow veins ; small cross-vein before the end of the 
first vein and nearly on the basal quarter of the discal cell ; posterior cross-vein straight, perpendicular, and 
near the hind border. 
Hab. Mexico, Xucumanatlan in Guerrero 7000 feet (7. H. Smith). 
A single male specimen. 
CHYLIZA. 
Chyliza, Fallén, Opomyz. Suec. p. 6 (1820). 
1. Chyliza varipes, sp. n., 3 °. 
Shining black ; head, scutellum, and legs rufous, the legs with blackish marks ; tips of the wings infuscated. 
Length 5°5 millim. 
Head rufous; front much broader than the eyes; ocellar knob, two stripes at the orbits, and two dots on the 
face, black. Antenne yellowish-rufous; arista yellow. Prvboscis pale rufous; palpi black at the tip. 
Thorax shining black, with more or less distinct yellow stripes; in some specimens the yellow colour 
predominates, and only a narrow margin and a broad band from above the shoulders over the pleure are 
black; scutellum yellowish-rufous. Abdomen shining black, the pointed ovipositor of the female rufous. 
Legs yellowish-rufous ; tips of the fore femora, a ring near the apex of the hind femora, and the inner side 
of the fore and hind tibic, blackish-brown, this colour more or less extended in some specimens, the darkest 
having the middle femora and tibie also blackish at the tip. Halteres yellow. Wings greyish-yellow, 
infuscated round the tip, most obscure at the end of the second vein; a slight shadow at the base of the 
first posterior cell; veins black; small cross-vein under the end of the first vein and on the basal third 
of the discal cell; posterior cross-vein straight and perpendicular. 
Hab. Mexico, Venta de Zopilote 2800 feet, Chilpancingo 4600 feet, and Amula 
6000 feet, all in Guerrero, and Teapa in Tabasco (H. H. Smith). 
Two male and four female specimens. 
BIOL. CENTR.-AMER., Dipt., Vol. II., Wovember 1897. 3a 
