BEES OF THE GENUS COLLETES FROM MEXICO 



CHARLES W. METZ 



Recently, when looking over a lot of Colletes from Mexico, in an efTort 

 to identify them, I was struck by the confusion in which the Mexican species 

 of this genus have been thrown by the descriptions of the early writers. A 

 large number, if not most of the known Mexican Colletes, were described by 

 Mr. Frederick Smith from specimens in the British Museum, and described 

 so briefly and superficially that it is impossible to identify the species without 

 access to the types. The only way in which these species can be straightened 

 out now is by new descriptions, and it is with the hope of forming a basis 

 for this that the present paper is prepared. 



Only twelve species have been included here, but as eleven was the total 

 number given by Prof. T. D. A. Cockerell in his catalogue of the Mexican 

 Apidse in 1899, I presume that these twelve include a good portion of the 

 known species, besides several that are undoubtedly new. 



Since the male genitalia furnish the best specific characters available in 

 this genus, I have figured them for each species of which I have males. As 

 can be seen by the figures it takes only a glance to distinguish species in 

 this way, and what is more, a few sentences will suffice to describe them 

 so that anyone can determine specimens from the descriptions. On working 

 out the genitalia I have followed the example of Mr. Myron H. Swenk, in 

 his admirable paper on, "Specific Characters in the Bee Genus Colletes." 



There are several sets of characters used in the earlier descriptions that 

 seem to me to be the cause of much of the confusion which now exists. 

 The coloration of the nervures in the wings, the color of the antennae (whether 

 or not lighter underneath), and even the color of the pubescence when it 

 is pale, is very variable in many cases and should never be used to distinguish 

 species, except in the case of the pubescence when the difference is very 

 marked. The exact length of the insect is another feature that varies greatly 

 in individuals of the same species and sex. All of these characters have 

 been included in the present paper in order that the descriptions may be 

 complete, but they are used, as supplementary, rather than as diagnostic 

 characters. 



It is not the expectation of the writer that all of the species herein 

 described will prove new, but that each description will be as complete a 

 one as possible of that species. For example, C. dilatata strongly resembles 

 the description of C. naiitlaiuis Ckll. ; but as the male of C. nauthinus is un- 

 known, I am describing both sexes under the name C. dilatata, and if they 

 prove to be C. iiautlaints, then so much the better for that incompletely 

 described species. 



