AKT. 16 NORTH AMERICAN ICHNEUMON-FLIES CUSHMAN 55 



The type has the propodeum basally red and the hind tarsus 

 entirely red. 



Genus POLISTIPHAGA Cushman 



PoUstiphaga Cushman, Jouni. Wash. Acad. Sci., vol. 15, 1925, p. 391. Qcno- 

 type. — i^Mesostcnufi arvalis Crcs-sou) =lfcsos/cHMs fiilvus Cresson 



It might be argued that this genus should be relegated to the 

 Hemitelini because of the areolation of the propodeum and the open 

 areolet, but the general appearance and structure indicate its affinity 

 with the Cryptini. All of the basal and apical areas are defined, 

 while the carinae separating the areas between the transverse carinae 

 may or may not be present, in the latter case perhaps adventitiously 

 due to the exaggeration of certain of the rugae lying in that region. 



The generic description is too recent and too detailed to require 

 repetition here, but certain features not there mentioned may be added. 

 Eyes slightly convergent below; frons with a median carina, but 

 without a horn; notauli complete; areolet elongate, open, recurrent 

 at or near position of second intercubitus ; discoidal cell broad at 

 base ; nervulus antef ureal ; nervellus inclivous, broken below middle ; 

 first abdominal segment decurved, sternite not or barely reaching 

 spiracles, postpetiole abruptly widened and much wider than petiole ; 

 abdomen rather broadly fusiform, coriaceous, impunctuate; sheath 

 shorter than first segment; ovipositor compressed, sagittate at apex. 



The following two species occur in the restricted region. Both are 

 parasitic in the nests of wasps of the genus Polistes: 



1. Thorax and abdomen hxrgely red fulva (Cresson). 



Thorax and abdomen black and yellow zonata, new species. 



POLISTIPHAGA FULVA (Cresson) 

 Fig. 6o 



Mesoatenusf fulvus Cbksson, Proc. Ent. Soc. Phila., vol. 3, 1864, p. 316, male. 



Type.— No. 1178, Acad. Nat. Sci. Phila. 

 Meiostenus arvalis Cresson, Trans. Amer. Ent. Soc, vol. 14, 1872, p. 163, female. 



Type. — No. 1171, Acad. Nat. Sci. Phila. 

 Mesostetiidea {ChristoUa) arvalis (Cresson) Viereck, Hym. Conn. (1916) 



1917, p. 329 and 330. 

 Polistiphaga arvalis (Cresson) Cushman, Journ. Wash. Acad. Sci., vol. 15, 1925, 



p. 391. 



Discussion based on types of both names, two paratypes of 

 arvalis, a homotype (Cushman) of fulva, and 38 other females and 

 18 other males, all but the types in the National collection. 



Fenude. — Length, 5-9 mm. 



Head, thorax, and abdomen opaque, finely coriaceous, the head 

 and thorax with additional coarser sculpture, the abdomen without 

 additional sculpture; frons medially rugulose; face finely punctate; 



