

DIPTEKA. 361 



Wings hyaline, with a slight infuscation before the third vein ; first vein reaching fully to the middle of 

 the wing ; hind cross-vein oblique, not quite parallel with the margin. 



2 . Arista only about half the length of that of the male, without disk ; the fore and middle tibia? each with 



a row of long bristles, which become stouter outwards. 

 Length 4*5-5 millim. 



Hab. Mexico, Chilpancingo and Tepetlapa in Guerrero, Cuernavaca in Morelos, 

 Atoyac in Vera Cruz, Teapa in Tabasco (H. H. Smith), N. Yucatan (Gaumer). 



The female of this species is very like P. comatus, but may be distinguished from it 

 by the absence of the small bristles on the upperside of the first joint of the fore tarsi. 



19. Psilopus comatus. 



Psilopus comatus, Loew, Neue Beitr. viii. p. 89 ' ; Mon. N. A. Dipt. ii. p. 262 2 . 



Ilab. North America, Middle States 1 2 .— Mexico, iUoyac in Vera Cruz (Schumann), 

 San Lorenzo, Cordova (M. Trujillo), Tepetlapa in Guerrero (H. II. Smith), N. Yucatan 

 ( Gaumer). 



20. Psilopus argentatus, sp. n. 



cf . Face viewed from in front deep green, otherwise silvery-pollinose ; antennae small, black, second joint 

 with a few moderately stout bristles ; front not excavated, except very moderately at the vertex, wholly 

 silvery, the deep blue ground-colour showing but faintly. Thorax entirely covered with thin silvery 

 pollen, on the dorsum, however, the violet ground-colour shows in some directions. Halteres yellow, the 

 stem infuscated. Abdomen violet, with thin and broken white pollen ; hypopygium small, black, the 

 appendages narrow, crooked, obscurely brown. Legs wholly black, tarsi plain ; fore tibiae with a partial 

 row of three or four bristles on the front side ; hind tibiae with much hair on the inner side, and a few 

 bristles on the outer side. Wings subhyaline, the fork making an acute angle with the fourth vein, and 

 a rounded right angle at its bend. 



Length 3*3 millim. 



Hab. Mexico, Tierra Colorada in Guerrero, Teapa in Tabasco (H. H. Smith). 



A single female has the legs coloured as in the male, the face moderately pollinose, 

 and the front shining. 



21. Psilopus hirtipes, sp. n. 



3 . Face metallic, wide above, the lower part slightly white-pollinose ; antennae rather large, the second joint 



with long, bushy, black bristles ; front broad, bright green. Thorax green, pleurae scarcely at all pollinose. 

 Halteres infuscated ; cilia of tcguloe large. Abdomen rather dull green, the incisures with narrow black 

 bands ; the bristles very numerous and large ; hypopygium small, blackish, with small appendages of the 

 same colour. Middle and hind coxae, as well as the last joints of the hind tarsi, black, the remainder of 

 the legs wholly brown and immature in appearance ; all the tibiae with noticeably coarse hairs ; fore 

 tibia and metatarsus equal in length, each with a thin row of long erect bristles on the hinder side, the 

 following joints plain. Middle tarsus about one and a third times the length of the tibia, with a few 

 minute scattered hairs under the first joint. Hind tibia with irregular long bristles on the outer side ; 

 hind tarsus with the second, third, and fourth joints a little compressed. Wings longer than in most 

 species of the same size, hyaline ; costa ciliated to the end of the second vein ; costal cell not especially 



widened. 

 9 . Bristles of the antennae much fewer and shorter ; legs paler brown and less hairy, while the tibiae, at 



least the middle ones, show prominent bristles ; wings shorter and broader. 

 Length 3'5-3'6 millim. 



Hab. Mexico, Omilteme in Guerrero (H. H. Smith). 

 biol. centr.-amer., Dipt., December 1901. 3 a 



