356 SUPPLEMENT. 



uniform row of about fourteen rather large bristles, and, in addition to these, with several other bristles 

 especially on the outer side near the base. Middle tarsi slightly yellowish at the base, otherwise black • 

 on the upperside of the first and second joints is a row of fine erect cilia, gradually decreasing in length, 

 sometimes not very easily seen on the second joint. Hind tibiae bearing on the outer side a row of stout 

 bristles, similar to those on the middle tibiae, but larger, and on the inner side also a rather bushy series 

 which are conspicuously large at the base only. Wings hyaline, a little clouded before the third vein 

 the fork making a right angle with the fourth vein and only gently bent, of the same shape as in 

 P. caudatus. 



2 • Halteres and middle tibiae yellow, wings hyaline. 



Length 4-1-4-6 millim. 



Hab. Mexico, Acapulco, Tierra Colorada, Medellin, Vera Cruz, Cuernavaca (H. H. 

 Smith), N. Yucatan (Gaumer). 



The female of this species is readily distinguished from that of P. caudatus by the 

 absence of hairs on the face. 



7. Psilopns inornatus, sp. n. 



A rather small dark species. Wings with cross-bands ; fore tibiae yellowish-brown. 



3 . Face and front dark bluish-green, the former scarcely dusted, the latter with some extremely delicate pale 

 hair; antennae small, black, the second joint with long and abundant black hair. Thorax bluish-o-reen 

 pleurae scarcely at all dusted ; halteres blackish. Abdomen deep blue, with broad black cross-bands and 

 rather strong bristles ; hypopygium small, black, with two short, cylindrical, black appendages, bearing 

 somewhat numerous and stout black hairs. Legs black ; femora on the underside with rather longer and 

 stouter bristles than usual, which in some lights appear dark in colour ; fore tibiae and a very little of the 

 base of their tarsi yellowish-brown ; all the tibiae and tarsi unusually destitute of hairs and bristles the 

 middle and hind tibiae, however, with a few small bristles ; hind tarsi just perceptibly stouter in the 

 middle than at the base. Wings with well-marked brown cross-bands, almost united on the fourth vein • 

 apical fork with a slightly rounded right angle in the middle. 



5 . Halteres yellow. 



Length 4-5*2 millim. 



Hab. Mexico, Tepetlapa in Guerrero, Cuernavaca in Morelos (H. H. Smith). 



8. Psilopus triseriatus, sp. n. 



Wings with dark markings ; femora black ; tibiae yellow, the hind ones a little darker ; hind tarsi blackish, 

 flattened near the tip. 



S . Face bright green, but little dusted ; front of the same colour, with only a few pale hairs at the sides : 

 antennae short, black, second joint with a few rather long bristles ; the pale hair of. the inferior orbit 

 quite conspicuous. Thorax bright blue-green, the pleurae but little dusted ; halteres infuscated; but not 

 very dark. Abdomen varying from green to blue, the last segment usually violet, the incisures each with 

 a narrow black band ; hypopygium small, black, with a pair of minute brownish-yellow appendages. 

 Coxae and femora black ; tibiae yellow, the hind ones brownish, especially near the base ; fore tibiae with 

 a scattered row of bristles on the outer side, otherwise bare ; middle tibiae with a row of about nine stout 

 bristles on the front side, and two or three small ones behind near the base ; hind tibiae with numerous 



; almost bristle-like hairs on the inner side. Fore tarsi one and a half times the length of the fore tibiae the 

 basal half or more of the first joint yellow, the following segments brown. Middle tarsi of similar length • 

 first joint as long as the tibia, bearing on its front side a dense row of erect cilia, longer than the thickness 

 of the joint : on the underside is a similar but smaller row, mixed with little stiff bristles, and on the 

 upperside a third row, not erect, and diminishing in size beyond the middle. Hind tarsi black, at the 



