122 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



Abdomen ovate, subpetiolate, the second and third segments the 

 kmgest, snbequal, the following short. 

 Legs as in Ceraphron. 



This genus, as here recognized, differs from Ceraphron in having a 

 stigmated marginal uervure and serrate antenntB in the male; and 

 from Lyfjocerm and Megasjnlus in having, at the most, only a single 

 mesonotal furrow. 



Forster characterized the genus as being without trace of a mesono- 

 tal furrow; but, as I have found to be the case in Ajyhanogmus, species 

 probably occur with and without a furrow. 



A single species is known in America. 



Atritomus americanus, sp. nov. 

 (PL VI, Fig. 9, J.) 



S . Length, 1.3'"™. Black, shining, feebly microscopically punctate; 

 antenna; brown ; legs reddish-brown, the coxte black ; abdomen i)iceous ; 

 mandibles black or piceous. Head transverse, a little wider than the 

 thorax. Eyes large, oval, bare. Antennae as long as the body, the 

 pedicel small, triangular, the first, second, third, and fourth funiclar 

 joints subserrate, the first the longest, a little nu)re than thrice as long- 

 as thick, the following a little shorter. Thorax scarcely narrowed be- 

 fore, with a delicate, central grooved line. Metathorax rounded be- 

 hind. Wing hyaline, pubescent, the stigma large semicircular, reddish 

 brown, the stigmal vein a little longer than the stigma. Abdomen 

 ovate, as long as the thorax, the petiole very short, rugose, the second 

 segment occupying about half of the remaining surface, the third and 

 fourth equal, longer than the following, the following very short; clasp- 

 ers flat, distinctly extended. 



Habitat. — Odenton, Md. 



Type $ in Coll. Ashmead. 



Described from a single specimen taken by Mr. E. A. Schwarz. 



Tribe II.— Ceraphronini. 



The species in this tribe can always be distinguished from those in the 

 Megasjrilini by the linear marginal nervure and the paucity of joints 

 in the female antenn;e, the mesonotum, at the most, having but a single 

 impressed line. 



The genera may be recognized by the aid of the following table: 



TABLE OF GENERA. 



FEMALES. 



Antennae O-jointed 3 



AntenniP 10-j()iiit<'(L 

 Wingless forms 2 



