Specific Characters in the Bee Genus Colletes — 3 
value as a character is greatly impaired; so much so that it is 
scarcely worth the trouble to describe it. The color of the wings 
and the amount of their clouding, except in a few cases, is usu- 
ally a character so variable as to be of comparatively little use in 
separating species. For instance, to use C. armatus again as an 
example, some specimens have the wings deeply clouded while 
others have them subhyaline, and between the two there is every 
gradation. . , | 
Accordingly, if we are to make our specific diagnosis of any 
general value in classification, the accurate description of the body 
puncturation must be emphasized, along with such few structural 
characters as do occur. In the females the presence or absence 
of spines on the anterior coxae, the simple or pectinate structure 
of the outer spur of the hind tibiae, the equally cleft or medially 
toothed claws, and the presence or absence of prothoracic spines 
are all characters of value. In both sexes the relative length and 
breadth of the malar space, the general shape of the face judged 
by the parallel or convergent orbits, the relative proportions of 
the antennal joints both individually and between each other, the 
stoutness or slenderness of the hind metatarsi, the depressions or 
reflexions of the margins of the abdominal segments, the pres- 
ence or absence of carinae or foveae on the last exposed ventral 
plate, and any other similar. characters are constant, and can be 
depended upon to serve, no matter what the condition of the 
pilosity of specimen may be. In the sculpture characters the 
general shape and puncturation of the clypeus, the presence or 
absence of a superior metathoracic face and the number and 
shape of the pits upon it if present, the sculpture of the enclosure 
on the base of metathorax (propodeum) and the degree of punc- 
turation of the basal abdominal segments and the disk of meso- 
thorax are the ones which show the best differences. By careful 
measurements and descriptions these differences can be intel- 
ligibly expressed, and in the majority of cases the species can 
be differentiated with reasonable ease and certainty. 
In the case of the males, however, we have an additional set of 
structures which abounds in characters of the greatest specific 
value, namely, the armatures and concealed seventh ventral plate. 
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