PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



issued 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 



Vol. 99 Washington : 1949 No. 3253 



THE NEARCTIC SPECIES OF EVANIIDAE 

 (HYMENOPTERA) 



By Henry Townes 



The family Evaniidae is an isolated group of parasitic Hymenoptera 

 most closely related to the Serphoidea. It differs from ail but a few 

 Hymenoptera in having the abdomen attaclied near the top of the 

 propodeum instead of down near the coxae, and from these few in 

 abdominal structure as follows : The first abdominal segment is cylin- 

 dric and slightly arched, and the rest of the abdomen is small, flattened, 

 circular or subcircular or subtriangular, and attached to the first seg- 

 ment by a free articulation. The Evaniidae differ from all other para- 

 sitic Hymenoptera in having a long anal lobe at the base of the 

 hind wing. 



The species of Evaniidae are parasitic in the egg capsules of Blatti- 

 dae and are most abundant in the Tropics, where their hosts are com- 

 monest. A few species parasitic on domestic cockroaches have been 

 widely distributed by commerce. Two of these species are established 

 in the Nearctic Region, and these together with nine native species 

 constitute our known fauna. The introduced species occur in cities 

 and are frequently collected on the windows of buildings. Of the 

 native species, which are to be found in woods, several are common in 

 the Southeastern United States and occur as far north as southern 

 Canada. West of the humid East, evaniids are occasional along the 

 southern border of the United States, and a single rare species has been 

 taken in central California. 



Previous comprehensive papers on the Nearctic Evaniidae include 

 a revision by Bradley (Trans. Amer. Ent. Soc, vol. 34, pp. 137- 

 162, 1908) and a literature compilation by Kieffer (Das Tierreich, 



831352 — i9 525 



