450 DIPTERA. 
but its head is without metallic-greenish tint,and the legs are of the same colour as 
the body, whilst in O. villade@ the two posterior pairs are black. 
2, Olfersia coriacea, sp.n., 9% (Zab. XIII. figg. 2, head and thorax; 
2 a, wing.) 
Brown, with the legs rufous and the wings brownish ; first vein ending above the small cross-vein; third vein 
reaching the costa at three-fourths of its length. 
Length 4-5 millim. 
Dark brown ; the eyes, the front (except its middle part), and the thorax glossy. Thorax before the trans- 
verse suture with two impressions on the disc; on the shoulders a rufous coniform prominence, with some 
short bristles at the tip ; before the sutellum a longitudinal impressed line and on each side a rather 
deep impression with some small scratches. Legs rufous, the hind femora elongate. Wings brownish ; 
first vein ending above the small cross-vein, which stands nearly at the middle of the wing’s length ; 
the auxiliary vein ending much nearer the base of the wing; third vein reaching the costa at three- 
fourths of its length; second basal cell half as long as the superior basal cell; beneath the end of the 
third vein a brown oblique shadow (in one of the specimens this is very distinct, in the other it is less 
conspicuous). Pe 2 omeys 0. aa , HAS Gay ef Bou wht, (AOR 
Hab. Mexico, Presidio (Forrerys GUATEMALA, Mirandilla (Champion). ve as whe ra 
Moths og PX 
Two specimens. 
8. Olfersia angustifrons, sp.n., ¢ 9. (Tab. XIII. figg. 3, head; 3a, wing.) 
Dark brown or blackish, with the legs obscure reddish and the wings brownish-hyaline ; frst vein ending 
before the small cross-vein ; third vein reaching the costa at three-fourths of its length ; auxiliary vein 
incomplete. 
Length 4 millim. 
More obscurely coloured than the preceding, and with the auxiliary vein (which accompanies the first vein for 
almost half its length) not reaching the costa; the front is scarcely as broad as the eyes and has a narrow 
glossy space at the sides and a glossy plate behind, which is notched in the middle; the proboscis is 
longer. The coniform prominences on the shoulders and the transverse suture of the thorax are distinct, 
but the other impressions of the latter are less conspicuous. The legs are rufous; the hind femora 
elongated. The first vein ends distinctly before the small cross-vein, which stands nearly at the middle 
of the wing’s length ; the second basal cell is much shorter than the superior one and retracted to near the 
base of the wing. 
Hab. Mexico, Teapa in Tabasco (H. H. Smith); Costa Rica, Rio Sucio (Rogers). 
A male from Mexico and a female from Costa Rica. 
Two other species of this genus have been described from Mexico :— 
Olfersia mexicana, Macq. Dipt. Exot. ii. 3, p. 278. 
villade, Dugés, La Naturaleza, (2) i. p. 20, t. 3. fig. 3 (Ornithomyia). 
The latter evidently belongs to the genus Olfersia, as the ocelli are wanting and the 
figure does not show the third basal cell (anal cell), which in Ornithomyia is always 
present. In these two species the head is metallic, a character separating them from 
the three others described above. 
