60 U. S. NATIONAL MUSEUM BULLETIN 216 



apically as a prominent point; areolet present, large; nervulus opposite 

 basal vein to beyond it by about 0.3 its length; nervellus broken above 

 the middle; prepectal carina various, according to the subgenus; 

 sternaulus a long, broad groove; metapleurum covered with coarse 

 punctures, or rarely the punctures are very sparse; propodeal carinae 

 as in figures 166,b to 169,b; propodeal spiracle a long slit; suture 

 between second trochanter and femur of front and middle legs obso- 

 lete; middle tibia with one spur; hind tibia with two spurs; front and 

 middle tarsal claws pectinate or apparently simple; hind tarsal 

 claws apparently simple; abdomen usually parallel-sided, strongly 

 punctate, usually strongly convex above; first tergite quadrate, 

 usually stout, its spiracle near its basal 0.25, its median longitudinal 

 carinae and sublateral carinae extending to its apex, usually strong; 

 second tergite often with a short weak sublateral carina; third to 

 fifth tergites occasionally with a thin median carina; epipleura of all 

 exposed tergites large and separated from tergite by a crease; eighth 

 and following tergites of male retracted; seventh and following tergites 

 of female retracted; female sixth sternite a large unspecialized sclerite. 



This genus is worldwide in distribution and contains a rather large 

 number of species. Collectors, however, consider Metopius to be 

 among the rarest of the ichneumon flies and very few persons have 

 ever found a species common. On one occasion we found Metopius 

 mimicus abundant, and we have sometimes taken more than one 

 specimen of Metopius xanthostigma and M. krombeini krombeini in 

 a day. Except for these three our catches of Nearctic species have 

 been only occasional and sporadic. 



Metopius adults frequent relatively dry, open places, and cruise 

 at about 0.5 to 3 meters height, at the tops of weeds or bushes, or 

 along the outside edges of woods, much in the manner of a Eumenes 

 or other eumenine wasps. In coloration they mimic wasps, particu- 

 larly eumenine wasps. In many species the resemblance is heightened 

 by the front third of the front wing being darker (to mimic the longi- 

 tudinally folded front wing of the Vespidae). In flight the end of the 

 abdomen is curled downward as in Eumenes. In the field, the longer 

 antennae is the most conspicuous character that identifies them as 

 ichneumonids. When captured, all the species (so far as observed) 

 give a high-pitched, wasp-like buzz. Metopius and Alomya are the 

 only ichneumonids known to buzz like this. 



Beginning with Clement (1930, Konowia, vol. 8, pp. 325-437), 

 there has been a tendency to divide Metopius into subgenera. In 

 some ways these subgenera are more like species groups, but since the 

 tradition of calling them subgenera seems to be established, it is con- 

 tinued in this paper, and expanded by the erection of two new sub- 

 genera. 



