TRANSACTIONS 



OF THE 



AMERICAN ENTOMOLOGICAL SOCIETY 



VOIvUNlB XXV. 



THE »SPE€IEIS OF PSEN IIVHABITI]«« AlUERICA 

 XORTH OF 91 EX ICO. 



BY WILLIAM J. FOX, 



The present paper is the result of some months study of these 

 insects. Much difficulty has been encountered in the work by the 

 want of distinct chai-acters in many of the species which necessi- 

 tated the using, in some instances, of certain differences, which, in 

 other genera, would be passed by as valueless for determination. 

 The writer is, therefore, unable to present the work with the same 

 degree of satisfaction as other circumstances might have conduced. 

 It is, however, the first monographic work on the genus, at least of 

 the American species, which fact may give it a standing in the 

 literature of hymenopterology. 



The author begs to express his thanks to Mr. Samuel Henshaw 

 for the opportunity of examining some of Packard's types. 



FE3fALES. 



1. Pygidial area as a rule narrow, with large punctures, and more or less de- 



pressed, scarcely margined laterally ; flagellum at most testaceous, rarely 



reddish beneath 2. 



Pygidial area broad and convex, without large puuctnres. sharply margined 

 laterally ; flagellum usually reddish beneath 12. 



2. Head with an unusually large process at base of antennie (second and third 



submarginal cells each receiving a recurrent nervure) 3. 



Head with a small tubercle at base of antenna? which usually sends out a 

 slender raised line extending upward 4. 



3. Petiole as long as hind femora, narrowed from middle to base, above with a 



single furrow which extends from base to middle, above at apex with a 

 depression ; hind ocelli bounded lateially by a deep, oblique furrow. 



frontalis. 



TRANS. AM. ENT. SOC. XXV. (1) .JANUARY, 1898. 



