Specific Characters in the Bee Genus Colletes 47 
Colletes hydrophilus Cockerell. 
1906. Colletes hydrophilus Cockerell, Annals and Magazine of Natural 
History, series 7, xvii, pp. 313-14, ¢ (March, 1906) ; original 
description. ; 
1907. Colletes hydrophilus Cockerell, University of Colorado Studies, 
iv, p. 240, 0 (June, 1907) ; in table of Boulder county, Colorado, 
species. 
_“§. Length about 10% mm. Black, with white pubescence, blackish on 
scutellum and posterior disk of mesothorax; apical half of mandibles dark 
reddish; labrum with a row of pits; malar spaces very short, more than 
twice as broad as long; eyes strongly converging below; face densely cov- 
ered with white hair; antennae dark, long, the flagellum stout, crenulate, 
its joints much longer than wide; third antennal joint dull velvety black, 
contrasting with the pruinose appearance of the rest of the flagellum; joint 
4 about or nearly as long as 2+3, 5 much longer than 4 (in C. gilensis it 
is only a little longer than 4) ; mesothorax shining, with uniformly-placed, 
well-separated, large and strong punctures; scutellum with close very 
large punctures; postscutellum with exceedingly dense, smaller punctures 
and a row of roundish pits along its anterior margin; area of metathorax 
with a very strong transverse ridge bounding the basal area, which is di- 
vided into very large quadrate spaces by about six carinae; lateral pos- 
terior faces shining, not much roughened, and not at all reticulate; pro- 
thoracic spines evident; tegulae shining black. Wings hyaline, clearer 
(and greyish, not at all reddish) than in C. gilensis; stigma ferruginous, 
nervures rather light fuscous; b. n. nearly reaching t. m.; second s. m. 
broader than high, receiving the first r. n. at or a little beyond the middle. 
Legs black, with white hair, spurs, and claws ferruginous; abdomen shin- 
ing, with very strong well-separated punctures, and narrow white hair- 
bands on the apices of the segments; last ventral segment with the long- 
itudinal carina barely indicated. 
“In my table in ‘Psyche,’ 1905, this runs straight to C. gilensis Ckll., 
but that is a considerably larger insect, and the sculpture of the metathorax 
is quite different. In Robertson’s table it appears to run closest to C. nu- 
dus Rob., but it is easily known from that by the very strong punctures 
of the abdomen. It has a very strong resemblance to C. opuntiae brevi- 
cormis . . . but differs entirely in the antennae, and otherwise in vari- 
ous small details.” (Original description. ) 
Type Locarity.—Boulder canyon near Boulder, Colorado; 
type in collection of. Professor T. D. A. Cockerell. 
The unique type was collected on June 26 while flying over 
damp sand. I have sent a metatype of C. nudus to Professor 
Cockerell for comparison with hydrophilus, and he finds that the 
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