A SYNOPSIS OF THE PETIOLATE WASPS OF THE FAMILY 



EUMENIDiE (HYMENOPTERA), FOUND IN 



AMERICA NORTH OF MEXICO. 



By Dwight Isely, 

 Bureau of Entomology, United States Department of Agriculture. 



The wasps of the family Eumenidse with petiolate abdomens, 

 found in America north of Mexico are included in two genera, 

 Eumenes Latreille and Zethus Fabricius. The following synopsis 

 is based on specimens contained in the U. S. National Museum. 

 Of the genus Eumenes the Museum contains 11 of the 13 

 hitherto described species and has large series of specimens of 

 several of these. Of the genus Zethus it contains specimens of 

 all of the five described species, but the number of specirhens 

 in all species is comparatively small. In addition to the 

 descriptions of new species included in this paper there are 

 redescriptions of the Say and Haldeman species and of a 

 number of other species which it seemed desirable to compare 

 with their allies. 



For the sake of clearness, descriptive terms used in this 

 paper which are not usually used by other hymenopterists or 

 whose usage is not always the same, may be defined as follows: 



Length. — The measurement from the front to the apical margin of the second 

 segment of the gaster. 



Lateral angles of the clypeus. — The angle produced by the meeting of the 

 apical and lateral margins of the clypeus. 



Pronotal lobes. — Lobes which project from either side of the prothorax into 

 the mesoepisternum a short distance below the tegulae. 



Metanotum. — The simple transverse plate which bears the hind wings. This 

 is the postscutellum of many authors. 



Propodeum. — The tergite of the first abdominal segment which has been 

 fused to the thorax. 



Gaster. — The abdominal segments after the constriction separating them 

 from the thorax, that is, all of the abdominal segments except the propodeuin. 



Petiole. — The first segment of the gaster, or the first abdominal segment of 

 many authors. It is not considered advisable to designate the petiole as distinct 

 from the gaster and preceding it, for with the majority of the species of this family 

 there is no petiole. 



Apical cordon of the petiole, — The salient margin or rim at the apex of the 

 tergite of the petiole. 



Dorsal angle of the second segment of the gaster. — The median dorsal line when 

 viewed laterally forms a more or less distinct angle which ordinarily marks the 

 maximum inflation of the segment. 



Lateral angle of the second segment of the gaster. — The lateral lines when viewed 

 dorsally form a more or less distinct angle as does the dorsal line, which ordinarily 

 marks the maximum lateral inflation of the segment. 



The writer wishes to thank Mr. S. A. Rohwer for testing the keys to species 

 and for criticisms and suggestions throughout the course of the studies herein 

 presented. 



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