1546] Fossil Diptera from Florissant 45 
of Palaentology, 1939, page 42, as occurring, but not described, 
in the Florissant beds. There is a species of Leptogaster de- 
scribed from the Tertiary formation of Kroatia, but prior is the 
first extinct species to be found in America. 
Asilus curculionis, n. sp. (Asilidae) 
(Plate II, Fig. 2) 
Legs rather short, unicolorous, apparently red, tarsi gradu- 
ally darker toward the tip, with uniform short rather coarse but 
not crowded dark brown pubescence; front femur with a row of 
eight long slender black bristles along its flexor edge; front 
metatarsus comparatively long, its sole with short stiff black 
bristles. This joint lacks the end, but enough is present to show 
that it is not of the abbreviated type of Echthistus. Middle 
tibiae with three macrochaetae present on the extensor surface; 
hind femora with about six bristles below, none visible on the 
upper side. The inner surface of the hind tibia shows a denser 
pubescence, as in some modern species. This surface is provided 
with two stout bristles, a character which among the recent 
species is almost invariably correlated with a long arista. Un- 
fortunately the head, which would have offered valuable generic 
characters, is wanting. Wing eleven millimeters long, clear 
hyaline, showing no darkening at the tip or posterior border, 
veins firm and dark, fourth vein much arched at basal third of 
second posterior cell, fourth posterior cell proximally pointed 
and merely touching the tip of second basal cell, anterior cross- 
vein placed a little beyond middle of discal cell. Body evidently 
darker than the legs, its macrochaetae black. 
The right wing and the left hind leg are preserved to a re- 
markable degree. Remains of the thorax, the other wing, and 
parts of the legs are also visible on the stone, but are torn apart 
and more obscure. Modern robberflies readily macerate and 
their members easily dissociate if kept moist after death, and 
care must be taken if relaxing them lest they fall to pieces. 
From the neuration the insect is most certainly to be included 
in the broad genus Asilus. Comparison with recent material 
shows limited but almost exact agreement with several of the 
species. The neuration of Asilus in its broader sense is quite 
rigid. The smaller genera or subgenera into which Asilus has 
been segregated derive their characters scarcely at all from the 
wings. Color, character of the vestiture, and particularly the 
