No. 2317. FIVE TRIBES OF ICHNEVMONINAE—ROHWER. 419 



podeum; spiracles of the first tergite close to the base, the distance 

 between them greater than the distance from one of them to the 

 anterior margin of the segment; first sternite completely separated 

 from the tergite; second sternite with the median tubercles at 

 about the middle; tergites not at all emarginate posteriorly; abdomen 

 of the male slightly widening posteriorly, about thi-ee times as long 

 as the head and thorax; second tergite with distinct lunulae. 



Merrill ^ considers that the markings of the black species are 

 subject to such variation that they cannot be used to separate species 

 and he would consider all of the American forms (except Jioferi) as one 

 species. It does not seem to the writer that this is correct. The 

 form with the black posterior orbits {alaskensis) is constant for the 

 specimens examined and it has a more restricted distribution. The 

 form with the annulated antenna (lineolata) while it has much the 

 same distribution as persuasoria, is confined to the Nearctic region 

 and v/ithout more evidence it seems unwise to consider that a species 

 would have a black antenna in one region and that in another it 

 would have a black or a white- annulated antenna. The writer 

 prefers to recognize, in the black forms, three species and would 

 separate the species by the following color characters : 



TABLE TO THE SPECIES. 



1. General color ferruginous; stigma yellow; wings pale brownish with a darker 



cloud along radius hoferi Rohwer. 



General color black; stigma black; wings uniformly hyaline or subhyaline.. 2. 



2. Posterior orbits black, immaculate, antennae black alaskensis Ashmead. 



Posterior orbits marked with yellow 3. 



3. Antennae black persuasoria (Linnaeus), 



Antennae with a pale annulus lineolata (Kirby). 



RHYSSA ALASKENSIS Ashmead. 



Rhyssa alaskensis Ashmead, Proc. Wash. Acad. Sci., vol. 4, 1902, p. 199. 

 Rhyssa skinneri Viereck, Trans. Amer. Ent. Soc, vol. 29, 1903, p. 87, 



Tyipe of alaskensis Cat. No. 5620, U.S.N.M.; type of skinneri 

 Acad. Nat, Sci. Philadelphia, Discussion based on types and speci- 

 mens listed below. 



The type of alaskensis Ashmead differs from the type of skinneri 

 Viereck in having the middle area of the face smooth and practically 

 without sculpture (in the type of skinneri the middle area of the 

 face has irregular dorsad-ventrad raised lines); in having a yellow 

 spot on the propodeum; and in having an entirely black mesepister- 

 num. Specimens from Hoquiam, Washington, collected at the same 

 time on a spruce log infested with horntail larvae show that the 

 sculpture of the face is variable and that the spots on the propodeum 

 and mesepisternum vary. The specimens exammed show the fol- 

 lomng variation: Length, 18-30 mm. Coxae usually black but in a 



•Trans. Amer. Ent. Soc, vol. 41, 1915, p. 142. 



