2L2 THE CANADIAN ENTOMOLOGIST. 



CLASSIFICATION OF THE ENTOMOPHILOUS WASPS, OR 

 THE SUPERFAMILY SPHEGOIDEA. 



BY WILLIAM H. ASHMEAD, ASSISTANT CURATOR, DIVISION OF INSECTS, 



U. S. NATIONAL MUSEUM. 



(Paper No. 3.) 

 Subfamily IV. — Thyreopinse. 



The absence of a distinct ridge, carina or crest on the mesopleura 

 just in front of the middle cox?e, an important structural character first 

 made use of by Kohl, the recurrent nervure in the front wings joining the 

 first cubital cell at or at least nearer the middle than the apex, and the 

 great differences noticeable in the antennae and the metathorax, readily 

 separate this group from the Crabroninse. 



To me the Thyreopinse seem to represent a large and distinct group, 

 allied to the others it is true, but yet quite distinct, and divisible into 

 many easily recognizable subgenera. It will be seen also that instead 

 of suppressing the genera erected by some of the older entomologists, 

 which fall in this group, and lumping them with Crabro, as has been done 

 by Kohl and Fox, I have instead recognized all of the genera of Latreille, 

 Dahlbom, Lepeletier, etc., and besides have founded some additional 

 genera. All of these, I think, can be easily recognized by the student, 

 with the use of the following table : 



Table of Genera. 



Ocelli arranged in an equilateral triangle or nearly \ , the lateral ocelli 

 about as far from each other as to the front ocellus ; thorax more or 

 less smooth or polished, shining, the metathorax feebly sculptured, 

 almost smooth, its posterior face sometimes rugulose 6. 



Ocelli arranged in an obtuse triangle . * . , the lateral ocelli being about 

 twice as wide from each other as to the front ocellus ; thorax with at least 

 the metathorax rugulose, opaque, often very coarsely sculptured, the 

 metanotum usually without, or with a poorly defined triangular or semi- 

 circular area, the posterior face often with a distinctly defined cordate 

 area ; the recurrent nervure joins the cubitus at or distinctly beyond the 

 middle of the first cubital cell ; abdomen always marked with yellow 

 above ; pygidium in ? always flat, triangular. 



Males 4. 



Females : 

 Superorbital foveae sharply defined, large oblique, or at least 



