ICHNEUMON-FLIES — GELINAE : MESOSTENINI 43 



carina in the form of oblique sublateral crests (weak in male, rather 

 strong in female), the carina absent medially except in some males 

 and except in some eastern Palearctic species, in males with the 

 carina complete medially it is weak in the middle, extends strongly 

 basad from the sublateral crests and its median portion is transverse; 

 areolet large, quadrate, its sides almost or quite parallel (except in 

 the species pallipennis and alutarius); ramellus short or absent; 

 nervulus at or basad of basal vein; mediella rather strongly arched; 

 nervellus broken near its lower end; axillus close to anal margin; 

 first tergite with a strong lateral subbasal tooth; spiracle of first 

 tergite well beyond the middle; postpetiole rather strongly expanded; 

 median longitudinal carinae of first tergite strong from base of tergite 

 to disc of postpetiole, basad of the spiracle forming dorsolateral 

 corner of the tergite; dorsolateral carina of first tergite strong distad 

 of spiracle, weak or absent basad; ventrolateral carina of first tergite 

 strong throughout; second tergite mat and with rather small punctures, 

 these moderately sparse to very dense; tergite 7 usually marked 

 with white; ovipositor sheath around 0.4 as long as front wing (except 

 in brachypterous specimens) ; ovipositor moderately compressed, 

 its tip more or less sagittate, varying from blunt to slender, its upper 

 valve sometimes weakly serrate between nodus and apex. 



Agrothereutes is a Holarctic genus, with nine species in North Amer- 

 ica and many more in Eurasia. Two of our species are Holarctic and 

 probably more will eventually be shown to have this type of distri- 

 bution. Most of them are northern. They parasitize sawfly and 

 lepidopterous cocoons. 



Females can be determined with relative certainty, particularly 

 because of some helpful characters in the ovipositor tip. Most males 

 can be correctly placed by the key and descriptions below, but the 

 variation in coloration of males is often confusing or deceptive, and 

 structural differences between them are minor and also variable. 

 Some care and experience will be required for uniformly accurate 

 determinations. 



Keys to the Nearctic species of Agrothereutes 



MALES 



(The male of montanus is unknown.) 



1. Wing veins white except for the subcosta and the stigma; temple with a prom- 

 inent upper posterior swelling, at a place where the occipital carina curves 

 sharply from its dorsal, more horizontal portion to its descending portion; 

 intercubiti strongly convergent anteriorly, the areolet pentagonal; a small 



blackish species 4. pallipennis, new species 



Wing veins dark brown; temple without an upper posterior swelling, the oc- 

 cipital carina evenly curved; intercubiti parallel or weakly convergent 

 anteriorly, the areolet quadrangular or subpentagonal 2 



