260 INSECTA. 
is triangular, or is very long and narrow, and almost lanceolate, 
as in 
Rapuium, Meig.(1) 
In the following, or 
Porpuyrors, Meig.(2) 
It is securiform or triangular, and with a hairy seta; the first joint 
is very short or indistinct. In 
MEDETERUS, Fisc. Meig. 
This seta is simple, with the first joint distinct and elongated. 
The last joint of the antennz, or the palette, is nearly oval. 
M. Macquart has formed a genus—Hydrophorus—with those spe- 
cies in which the seta is altogether terminal. Those in which the 
insertion is dorsal alone compose the genus Medeterus(3). 
There, the third joint of the antenne is almost globular. The 
seta is always hairy. If it be terminal, we have the genus Curyso- 
rus; if it be inserted a little underneath, that of Psrropus; and finally, 
if it arise lower down or near the base, DiarHorus, which genus, 
by the almost spherical head, nearly entirely occupied by the eyes, 
in the males, appears to us to lead to the family of the Platypezina 
of Meigen. The wings, ocelli, and some other characters drawn 
from the parts of the head, confirm those we have described. We 
cannot, however, enter into similar details here(4). 
The Platypezina of M. Meigen, from which Macquart has very 
properly removed the genus Cyrtoma, and to which we unite that of 
Scenopina and his family of the Mecacernuati(5), consist of Diptera 
very analogous in their proboscis, antenne and wings to the Doli- 
chopis but the body is depressed, the head hemispherical and almost 
entirely occupied by the eyes, at least in the males. The palpi are 
- (1) Idem. 
(2) Idem. 
(5) Idem. i 
(4) Meig., and Macquart. The genus Lonchoptera, arranged by Meigen with 
the preceding genera, is greatly removed from them. See the tribe of the Mus- 
cides. : 
(5) We form them into a small tribe under the denomination of CePpHaLoprsIDEs. 
