ART. 15«. REVISIOlsr OF SUBFAMILY PLATYGASTERINAE — FOUTS. 19 



VII. Genus ERITRISSOMERUS Ashmead. 



Eritrissomerus Ashmead, Bull. 45, U. S. Nat. Mus., 1893, p. 298. Monobaaic. 

 Genotype. — Eritrissomerus cecidomyiae Ashmead. 



This genus differs from Platygaster Latreille only in having the 

 process between the antennae acute at apex, not truncate or emar- 

 ginate. If one is unable to see this projection he can not place his 

 specimen in the correct genus. Ashmead considered the extraordi- 

 nary structure of the male antennae peculiar to this genus, but I have 

 specimens in my collection which have the antenna precisely as in 

 Eritrissomerus cecidomyiae, the type of the genus and'which have the 

 process between the antennae truncated at apex. I consider this 

 genus an artificial one and used it merely for convenience. It should, 

 I believe, be included in the genus Platygaster but there is no objec- 

 tion to keeping it separate for the present. 



There are five species now included in Eritrissomerus. All are from 

 eastern North America, the specific localities being Jacksonville, 

 Florida; Hull, Canada; Albany, New York; and Cabin John, Mary- 

 land. My new species parvus was found at Cabin John. 



The habits of two of the species are known, or rather partially 

 known. E. cecidomyiae is jiSiT&sitic on &, Cecidomyid infesting hickory 

 and E. novehoracensis is recorded as having been reared from a 

 Cecidomyid gall. 



The following table serves to distinguish aU the species included 

 in the genus, there being no exotic forms described. 



TABLE TO SPECIES. 



1. Body rufo-piceous; antennae, except club, yellow 1. pallipes Harrington 



Body black 2. 



2. Vertex rugose, with large transversely directed carinae. 



2. cecidomyiae Ashmead. 

 Vertex aciculate or shagreened 3. 



3. Vertex transversely aciculate; legs yellow, rarely somewhat infuscated. 



3. noveboracensis Brues. 

 Vertex shagreened; front legs golden yellow; middle and posterior legs infus- 

 cated in part 4 . 



4. Abdomen longer than the thorax 4. parvus, new species. 



Abdomen as long as the thorax 5. floridanus Ashmead. 



1. ERITKISSOMERUS PALLIPES Harringten. 



Eritrissomerus pallipes Harrington, Trans. Royal Soc, Canada, vol. 5, 1900, 

 p. 191. 



The best I can do is to reproduce the original description which I 

 do merely for the sake of completeness. I can not hope that the 

 species will be recognized by it, but it is well to have the description 

 more accessible. Harrington does not say whether the antenna! proc- 

 ess is acute or not, but it is reasonable to suppose that it was since 

 that character is the only one really peculiar to the genus 



