NORTH AMERICAN HYMENOPTERA. 129 



THE CRABRONIX.E OF BOREAL, A.^IERICA. 



BY WILLIAM J. FOX. 



The Crabroniii?e form a well-marked subfamily of the Sphegidse, 

 and includes the genera Entomognathus, Anacrahro and Crabro, and 

 has a vast number of described species in the world. This is par- 

 ticularly true of Europe, which has in the neighborhood of one 

 hundred and fifty known species ; fully two-thirds of that number 

 are treated of in this paper as occurring in Boreal America, includ- 

 ing Canada, the United States and the peninsular of California 

 (Lower or Baja California) ; and it is safe to say this number will be 

 greatly increased in the near future, and that our fauna will be found 

 to be fully as rich in species as that of Europe. The species of 

 Crabro are in many cases difficult to separate, and this, together with 

 the fact that our only existing monograph is faulty as to the arrange- 

 ment of the species, allied forms in many cases being placed in dif- 

 ferent groups, and the overlooking of important characters, and the 

 magnification of minor points, has caused confusion in more than one 

 case, as I know from experience. I was fortunate in having the types 

 of nearly all of Packard's species, which aided materially in straight- 

 ening out many points, which otherwise would have remained ob- 

 scure. Cresson's types were also of much assistance. It must not 

 be understood for an instant that I mean to invalidate the work of 

 the author of the above-mentioned monograph, whose Revision of the 

 Fossorial Hymenoptera of North America, published nearly thirty 

 years ago, was an epoch of importance to American Hymesiopterology. 



Crabro divides into numerous groups, some being well marked 

 and others difficult to separate, or differing in points only to be 

 found in one sex. Many of these groups of species were of generic 

 importance in the eyes of Lepelitier de St. Fargeau and his colleague 

 Brulle, who, in their Monographic du Genre Crabro,. recognized 

 eleven genera, ten of which were of their own making. Dahlbom, 

 in his Hymenoj)tei"a Europsea, eleven years later reduces these to the 

 value of subgenera, evidently, and adds three new subgenera. 

 Shuckard, before the publication of Dahlbom's work, rejects all of 

 the names proposed by St. F. and Brulle, and Smith, in Catalogue 



TRANS. AM. ENT. SOC. XXII. (17) MAY, 1895. 



