38 DIPTERA. 
This species is of a more elongate and cylindrical form than the two foregoing. I 
regard as the female of this insect a specimen taken in Mexico (Orizaba) in December 
1887 by Messrs. H. H. Smith and F. D. Godman. This example is smaller (7 millim. 
only), and of a more metallic colour; the arista is more slender; the abdomen is less 
cylindrical and without reddish tinge at the sides, the last segment, however, being 
rufous; and the claws and pulvilli are very short. In all other characters it agrees 
with the above-mentioned male specimens. 
GYMNOMMA, gen. nov.* 
Agrees in most points with Micropalpus ; but differs in having the eyes bare, a less elongated abdomen, the 
macrochete absent from the middle of the second and third abdominal segments, and the fourth vein not 
prolonged beyond its point of curvature. The antenne are broader towards the end, the second joint is rather 
elongated, the third joint is twice as long as the second, and the arista is distinctly jointed. Vibrissee at 
some distance above the oral margin. Proboscis moderately long; palpi absent, or at least not perceptible. 
Abdomen ovate ; the first segment abbreviated. Apical cell notably before the tip of the wing; posterior 
cross-vein on more than two thirds of the apical cell. 
wi 
1. Gymnomma nitidiventris, sp.n. 9. (Tab. M-figg. 17; 17a, head in 
profile.) 
Yellowish-cinereous; head white; abdomen shining black; antenns and frontal band rufous; legs black ; 
wings greyish. 
Length 9°5 millim. 
Head sericeous-white, with grey reflections; face perpendicular, a little prominent at the oral margin; above 
the vibrisse two and under them several shorter bristles; beard white; front broader than the eyes; 
median band ferruginous, as broad as the sides; frontal bristles robust, three of them descending beneath 
the base of the antenne, and two placed laterally near the orbits of the eyes; on the cheeks a row of 
weak hairs. Antenne rufous; second joint enlarged towards the end, on the upper part with rather long 
bristles; third joint twice as long as the second, and broader, infuscated towards the end ; arista thickened 
to beyond the middle. Thorax and scutellum yellowish-cinereous ; thoracic dorsum with four black stripes, 
which, however, are not very distinct; pleure blackish; macrochete abundant and stout. Abdomen 
shining black; fourth segment laterally with white reflections; the macrochete placed thus:—four at — 
the hind margin of the second segment (two dorsal and one on each side), six at the hind margin of the 
third segment, and several on the fourth segment. Legs black; front femora with a row of bristles on 
the upperside as well as on the underside; posterior femora only with a row on the underside and two 
bristles close together above near the apex; tibiee outwardly with many bristles, those on the front pair 
shorter. Tegule yellowish-white. Wings grey, at the base a little infuscated ; small cross-vein placed 
on the middle of the discal cell; curvature of the fourth vein with an acute angle; apical cross-vein 
incurved at the base; posterior cross-vein scarcely bent outwards. 
Hab. Mexico, Ciudad in Durango 8100 feet (Lorrer). 
A single female specimen. 
NEMOCHAETA, gen. nov.f 
General facies of Micropalpus, but with fully developed and even robust palpi. Eyes bare. Front rather 
prominent, broader in the female; frontal bristles strong, descending on both sides in a double row, and 
somewhat irregularly, beneath the root of the antenne. Face retracted; the oral margin a little 
* yupvos, bare; dupa, eye. + vépw, divide; xairn, bristle. 
