292 
COSTA RICAN DIPTERA 
are before me two females from Carillo, Costa Rica, two females 
from Ecuador and one female from Bartica, British Guiana, 
collected by Parish. AVhile walking along the railroad at Los 
Amates, Guatemala, I procured a female specimen of this species 
from a cow where it was taking blood. From specimens at hand 
the range may be given as Guatemala to Ecuador and British 
Guiana. 
Erephrosis niger Ricardo 
One female specunen from Peralta Station, Costa Rica, August 
10, 1909. Miss Gertrude Ricardo described the species in Annals 
and Magazine of Natural History, Series 7, Volume vi, page 292, 
from a male from Surinam. There is before me a male taken at 
Bartica, British Guiana, by H. S. Parish, March 20, 1901. Noth- 
ing on the habits of the species is available. [This is the species 
mentioned as Pangonia pyrausta in our “A Year of Costa Rican 
Natural History,” page 258. — P. P. Calvert.] 
Chrysops tanyceras Osten Sacken 
1886. Chrysops tanyceras Osten Sacken, Biol. Cen.-Am., Dipt., i, 46. 
More than a dozen specimens taken at Peralta Station, March 
10, 23, 25 and 26, 1910. There are four species of Chrysops from 
New Mexico, Mexico and Central America with the first and 
second segments of the antennae elongate and the third segment 
abnormally short. 
They may be separated by the following table: 
1. First antennal segment decidedly longer than the second 2 
First and second antennal segments nearly equal in length 3 
2. Whole body, including the wdngs and legs, uniformly black or dark brown. 
melanopterus Hine 
Body brown, abdominal segments with an apical gray margin which ex- 
pands into a small triangle at the middle, legs mostly yellow, wings hya- 
line with the cross-veins and furcation of the third vein margined with 
brown tanyceras Osten Sacken 
3. Body nearly uniform brown without perceptible gray on the sides and pos- 
terior margins of the thorax and abdominal segments, .ceras Townsend 
Body brown with distinct gray on the sides and posterior margins of the 
thorax and abdominal segments megaceras Bellardi 
It is very easy to distinguish melanopterus on account of its 
uniform black color, but the other three species are much alike 
in general appearance. The frontal callosity is normal for Chry- 
sops in ceras, but of a different type in the others. 
