no. 1834. NEW SPECIES OF STREPSIPTERA— PIERCE. 499 



cially as females are now at hand from several of the so-called genera 

 recognized by Ashmead. These parasites are too closely allied to 

 warrant even subgeneric separation. 



PSEUDOXENOS ARVENSIDIS, new species. 



Host.—Odynerus (Leionotus) arvensis Saussure, Carlinville, Illinois, 

 Described from one female collected August 2 by Charles Robertson. 



Female. — Length of cephalothorax 1.16 mm., breadth 1.25 mm., 

 breadth of head 1.05 mm., distance between mandibles 0.23 mm. 

 Cephalothorax orange brown, the margins very dark, and the anterior 

 half, except in front of opening of brood canal, dark; posterior half 

 of disk lighter. Cephalothorax broader than long, constricted at 

 base, broadest behind spiracles, thence more or less evenly convex 

 on sides and apex, apex almost imperceptibly truncate; spiracles 

 lateral and barely prominent: mandibles oblique, emarginate at 

 apex with curved tooth on inner angle. 



Type— Cat. No. 13700, U.S.N.M. 



PSEUDOXENOS ERYNNIDIS, new species. 



Host. — Odynerus erynnys Lepeletier, Inverness, Florida. Described 

 from one female collected by Charles Robertson. 



Female. — Length of cephalothorax 1.32 mm., breadth 1.39 mm., 

 breadth of head 1.08 mm., distance between mandibles 0.26 mm. 

 Cephalothorax orange brown, with apex yellow, behind which is a 

 quadrate dark spot as wide as the opening of the brood canal, mar- 

 ginal area from here back darker than disk, and margin from base of 

 head very dark to base of cephalothorax. Cephalothorax broader 

 than long, constricted at base, broadest immediately behind the 

 spiracles, lateral margins between base of head and spiracles not 

 very oblique, but at base of head strongly angled and thence oblique, 

 slightly sinuate; apex strongly convex; spiracles lateral, barely 

 prominent; mandibles distant, very oblique, deeply emarginate at 

 apex, forming an acute tooth on inner angle, and a rounded lobe on 

 outer angle. 



Type.— Cat. No. 13701, U.S.N.M. 



This species differs considerably in form from the others so far 

 described. 



PSEUDOXENOS FORAMINATI, new species. 



Host. — Odynerus foraminatus Saussure, Trenton, New Jersey. 

 Described from one female collected July 5, 1907. 



Female. — Length of cephalothorax 1.02 mm., breadth 1.04 mm., 

 breadth of head 0.85 mm., distance between mandibles 0.17 mm. 

 Cephalothorax dark brown, with part of head between mandibles 

 yellow, and a small area at base of disk lighter brown, margins very 

 dark, but a lighter round area indicates location of spiracles. Cepha- 

 lothorax almost as long as broad, convexly narrowed to base from 



