270 



BRUES. 



Polymecus (Dolichotrypes) hopkinsi Crawford & Bradlev 



('11, p. 124). 



Mr. W. F. Fiske obtained numerous females of this species on May 

 19 near Boston, on cut stumps, behaving as described by Crawford and 

 Bradley. From some of his specimens which he kindly gave me at the 

 time, I have been able to compare the South and the North American 

 species. 



The genus Dolichotrypes is probably not distinct from Polymecus 

 according to Mr. Fonts who has given much time to taxonomic studies 

 in this family. I have retained it above in subgeneric form to include 

 the two species here dealt with. Other species of Polymecus have the 

 apical prolongation of the abdomen to a lesser degree as do also some 

 species in other genera such as Sactogaster. In addition to the " tail," 

 the females of the latter genus possesses a sac-like enlargement of the 

 venter probably associated with the egg-laying apparatus. A Euro- 

 pean species was bred more than half a century ago by Winnertz 

 ('53) from Contarinia (Cecidomyia) pisi, but further observations on 

 this interesting genus do not appear to have been made. 



In two other Serphoid families there is a somewhat similar ventral 

 swelling of the second segment which extends forwards ; the Diapriid 

 Cardiopria Dodd and the Belytids Acanosema Kieffer and Cardio- 

 spilus Kieffer are thus modified. 



Gastrotrypes, gen, nov. 



Antennre 9-jointed, with a minute hyaline joint-like connection in 

 addition, between the pedicel and first flagellar joint. Maxillary palpi 

 consisting of two equal, elongate joints; labial palpi one-jointed, elon- 

 gate. Head about twice as broad as thick, a little wider than the 

 thorax. Ocelli in a broad triangle, the lateral ones much closer to the 

 eye than to the median ocellus. Parapsidal furrows wanting. Scutel- 

 lum highly convex, without spine, not deeply separated from the 

 mesonotum which bears a large shallow impression at each side behind ; 

 pubescent, especially at the sides apically. Abdomen with the first 

 four segments forming an oval mass; second segment quadrate; third 

 and fourth short, much narrowed; fifth very narrow, sometimes very 

 much elongated; sixth segment membranous, very slender, capable 

 of being greatly extruded. Wings veinless, with very weak discal 

 hairs; with prominent marginal cilia apically behind. 



Type species: G. spatulatus sp. nov.; other included species: G. 

 caiidains sp. nov. 



