ICHNEUMON-FLIES OF AMERICA: 1. METOPIINAE 167 



19. Stethoncus, new genus 



Figure 177,a 



Front wing 3.5 to 4.2 mm. long; body punctation fine and weak; 

 combined face and clypeus strongly convex transversely, weakly 

 convex vertically, the upper edge of face produced as a broad triangular 

 point which is turned backward between the antennal bases almost 

 at a right angle and separated from rest of face b} 1, a strong transverse 

 carina; frons rather strongly convex, without a median process or 

 carina; head in profile sloping obliquely from hind margin of hind 

 ocelli to point usually occupied by occipital carina; temple strongly 

 convex; occipital carina very weak laterally, elsewhere absent; cheek 

 about 1.3 as long as basal width of mandible; mandible broad, with a 

 carina along its lower edge, rectangular with its apex obliquely 

 truncate, its upper tooth wide and short, its lower tooth very wide 

 and very short, its apex oblique; labrum concealed; flagellum filiform, 

 rather short, especially in female; upper margin of pronotum very 

 wide and swollen; propleurum strongly swollen and convex; scutel- 

 lum convex, rather long, without lateral carina; areolet absent; 

 intercubitus separated from second recurrent by about 0.7 its length; 

 nervulus postf ureal by about 0.5 its length; nervellus strongly in- 

 clivous, weakly broken near its lower 0.2; prepectal carina complete, 

 its dorsal end joining front end of subtegular ridge; sternaulus repre- 

 sented by a broad, short, w r eak impression; metapleurum polished, 

 with a band of small setiferous punctures along its upper margin, 

 elsewhere impunctate and hairless; propodeum moderately long, 

 declivous beyond its apical transverse carina, completely carinated 

 except that median basal area and areola are confluent; propodeal 

 spiracle small, round; legs stout; base of hind coxa weakly produced 

 behind its socket so that it does not form a distinct posterior shoulder; 

 second trochanter of front and middle legs incompletely fused with 

 its femur; spurs of middle tibia rather short, of approximately equal 

 length; tarsal claws apparently simple; abdomen somewhat narrowed 

 basally; first tergite narrow basally, its spiracle near its basal 0.4, 

 its lateral longitudinal carina strong and complete, its median dorsal 

 carinae strong basally, fading out near apical 0.3; second tergite 

 without dorsal carinae; epipleurum of first tergite vestigial, of second 

 tergite very narrow, of third and following tergites wide; seventh 

 tergite not retracted in either sex. 



Genotype : Stethoncus arcticus, new species. 



The generic name is from the Greek "stethos" (breast) plus "onkos" 

 (tumor), referring to the swollen propleurum. 



This genus contains the genotype from arctic America, described 



451582—59 12 



