298 
COSTA RICAN DIPTERA 
scribed the genus Eristicus without iiientionmg any species. 
Some years later he stated that species of this genus are found in 
Ainerica. In 1878, Ostcn Sacken showed that what we now 
know as Erax maculatus is the type of Eristicus and changed the 
name to Neoeristicus, because Wesmael had proposed the former 
as a generic name in another connection in 1844. In 1861, Bel- 
lardi described nigripes and villosus and placed them in Eristicus, 
but villosus is known now to be the same as Erax maculatus and 
Dr. Kertesz includes this in the genus Erax in his recent cata- 
logue. In 1857, Bigot proposed Eicherax as a generic name, 
and mentioned as the type species Erax simplex from South 
America. A study of numerous specimens of what Bellardi 
called Eristicus nigripes shows that the species belongs to Eiche- 
rax rather than to Neoeristicus, on account of the venation; thus 
the latter is left without any species, in which case there is no 
use to retain it. 
There are before me more than a dozen specimens of what I 
call Eicherax nigripes, ranging from Cordoba, Mexico to San 
Sebastiano, Brazil, including two from San Domingo, Costa 
Rica and several from Bartica, British Guiana. 
Since Bellardi described the species Schiner is the only one 
whom I know to have mentioned additional specimens. In his 
Novara Reise, he mentions having a pair from South America 
and suggests changing the name to hellardii, because nigripes 
was preoccupied in the genus Erax. The species cannot be in- 
cluded in the genus Erax because of the venation and other char- 
acters, consequently nigripes still stands. 
Wdiole body and legs black in ground color, wdngs uniformly pale brown, 
venation as in Asilus. Length, 12 to 15 milUineters. 
Gibbosity of the face prominent, mystax composed of black bristles above 
and white ones below, beard white and fine, antennae, palpi and proboscis 
black, front and face rather wide, covered with pale yellow pollen, sides nearly 
parallel, bristles of the upper part of the occiput black; disk of the thorax 
with a wide black stripe, which is narrowly divided longitudinally at the middle 
by a fine gray fine, sides of the thorax, including the coxae and most of the 
scuteUum, yellow pollinose; legs black with black bristles, front and hind 
tibiae and tarsi with golden pile on inner side; wings uniformly pale brown, 
furcation of the third vein opposite the apex of the discal cell, no appendage, 
posterior branch of the third vein turns back to meet the costa far beyond the 
tip of the wing as in Asilus. Abdomen black with silvery white distributed 
as follows: two transverse spots on dorsal margin of the first segment, pos- 
terior margins of second and third segments except venter and a rather narrow 
