PROSENA. 215 
the abdominal segments. The others differ in some respects from it: P. valida is the 
type of the genus Mochlosoma, Br. & v. Berg., and P. lacertosa, P. tessellans, and 
P. melena each possess characters which might be taken as generic, but I prefer at 
present to keep them united in the old and well-known genus Prosena. 
1. Prosena lacertosa, sp. n.,3 9. (Tab. V. figg. 1; 1a, head.) 
Yellowish-rufous; thorax cinereous, with obsolete dark lines; antenne, palpi, and legs rufous, the tarsi black ; 
abdomen with discal and marginal macrochete. 
Length 10-13 millim. 
Of a vigorous form and a yellowish-rufous coloration. Head with whitish reflections; front of the male 
narrowed behind in such a manner that the eyes are nearly contiguous, that of the female broader than 
the eyes ; frontal band brownish-red, on “both sides with a row of bristles, which descends as far as the 
root of the antennz ; cheeks broad; beard yellowish. Antenne short, rufous ; third joint brown on the 
apical half, a little longer than the second, which is prominent and bears one or two rather long bristles ; 
arista black, thickened in its proximal half, and moderately long-plumose. Proboscis black, nearly as 
long as the head and thorax; palpi small, rufous, bristly at the end. Thorax yellowish-cinereous, with 
five not very distinct dark lines, the three median of which are close together at the front side and the two 
outer ones interrupted at the transverse suture ; scutellum almost of the same colour as the thorax, but 
somewhat more ochraceous ; in the male the thoracic dorsum and the scutellum are beset with black pile, 
this being also present in the female, but shorter and less conspicuous. Abdomen ovate, convex, rufous, 
slightly transparent, with silvery-yellowish-white reflecting spots; some specimens have a blackish dorsal 
band, which is more or less interrupted on the incisions, in others this band is quite absent ; macrochete 
are on the hind margins of the segments, and, in addition, there are two discal macrocheste on the second 
and third segments and some in the middle of the anal segment. Legs rufous, with black tarsi; coxe on 
the front side densely clothed with black pile, which in the female is more bristly ; femora and tibize with 
many long bristles; first joint of the tarsi shorter than the tibie ; foot-claws and pulvilli elongate in the 
male, the pulvilli greyish. Tegule rufous. Wings rufous at the base and along the basal part of the 
costa, for the rest greyish ; veins testaceous, fuscous towards the apex; small cross-vein before the middle 
of the discal cell ; curvature of the fourth vein with an acute angle; apical cross-vein concave; posterior 
ceross-vein slightly curved. 
Hab. Mexico, Ciudad in Durango 8100 feet (Forrer). 
_ Three male and three female specimens. 
Prosena longitarsis, Macq. (Dipt. Exot. ii. 3, p. 92, t. 11. fig. 2), from Bogota, seems 
to be very nearly allied to this species; but differs by the somewhat thickened and 
recurved terminal lips of the proboscis, the whitish-grey colour of the thorax, the 
scutellum fulvous only at the hind margin, and the first joint of the tarsi as long as the 
tibize. 
2. Prosena valida. (Tab. V. figg.2; 2a, head.) 7) "97 CUS den 
Mochlosoma validum, Brauer & v. Bergenst. Denkschr. der kais. Akad. der Wissensch. Wien, lvi. 
pp. 126, 168, t. 8. fig. 102. 
Black ; head greyish-white ; thoracic dorsum anteriorly dark grey, with obsolete black stripes ; abdomen with 
discal and marginal macrochete ; wings brownish-grey. 
Length 10°5 millim. 
g. Front narrowed towards the vertex and there narrower than the eyes; frontal band broad, blackish-brown ; 
frontal bristles scarcely descending beneath the root of the antenne ; posterior orbits of the eyes with long 
bristly hairs ; cheeks inferiorly broad, nearly equalling half the longitudinal diameter of the eyes; face 
yy of ( 
) PL SORK AED De pa. 
