DIPTEEA. 365 



12. Abdomen pale at the base above (U.S.; Cuba) [variegatus, Loew.] 



Abdomen not pale at the base above (Cuba) [castus, Loew.] 



13. Fore femora with slender erect bristles below (U.S.) [tener, Loew.] 



Fore femora without such bristles 14. 



14. Hind margin of the pleurse yellow 15. 



Hind margin of the pleurse green (Mex.) mexicanus, sp. n. 



15. Abdomen above with a basal yellow band, the remainder green (U.S.) . [itnifasciatus, Say.] 

 Abdomen with several bands, including the greater part of the first four 



segments (U.S.) \rotundiceps, Aldr.] 



Note. — Gnamptopsilopus Jlavicoryiis, Aid., from St. Vincent, W.I., known only from the female, is not included. 



1. Gnamptopsilopus dimidiatus. 



Psilopus dimidiatus, Loew, Berl. ent. Zeitschr. vi. p. 216 ' ; Mori. N. A. Dipt. p. 246 2 . 

 Hab. Mexico 1 2 , Cuernavaca in Morelos (H. H. Smith). 



Two males, one in bad. condition. These seem to have paler femora and darker 

 tibise than indicated by Loew's description ; the hyaline space at the tip of the win^ 

 hardly occupies one-fourth of the entire wing. In spite of the black cilia of the tegulae, 

 the species belongs to the present genus, as there are only two large bristles on the 

 scutellum, and the third vein of the wing is strongly bicurvate at the tip. 



G. dimidiatus was included by Osten Sacken amongst the unidentified species of 

 Psilopus, antea, p. 214. 



2. Gnamptopsilopus infumatus, sp. n. 



c? . Face and front bright green, the former in a certain light white-pollinose. Antennas black. Thorax and 

 abdomen bright green ; pleurae in an oblique light with considerable white pollen ; cilia of tegube brown 

 or blackish ; halteres pure yellow ; hypopygium globular, blackish, with small, hairy, broAvnish-black 

 appendages. All the femora and tibise, and the fore coxae, are yellow, the last long, with three black 

 bristles at the tip ; middle and hind coxae black, the trochanters brownish. Wings large and broad, with 

 a broad, but ill-defined, brownish band extending from the costa to the hinder end of the cross-vein, the 

 latter forming its outer boundary ; on the apical side of this band the wing is hyaline, the basal side, 

 however, is slightly inf uscated ; the costa is ciliated to a little beyond the end of the second vein ; the third 

 vein is almost exactly parallel with the margin, except at the tip ; the cross-vein is long, with the 

 convexity outward. 



In the female the cilia of the costa are scarcely at all perceptible, the brown mark is absent from the wiug, 

 and the cilia of the tegulae are paler, in some lights yellowish ; but the black bristles of the fore coxae are 

 present. 



Length 3-4-3 millim., the smaller being the female. 



Hab. Mexico, Amula and Chilpancingo in Guerrero (H. H. Smith). 

 Three males and one female. 



3. Gnamptopsilopus mexicanus, sp. n. 



<? . Face so densely white-pollinose that the ground-coloar is almost hidden; the upper part is very wide. 

 Antennae yellowish, the apex infuscated. Front white-pollinose, the violet ground-colour but faintly 

 showing through. Thorax pure green, sparsely dusted with white along the front; pleurae wiih sparse 



