ICHNEUMON-FLIES — GELINAE : MESOSTENINI 



403 



22. Genus Acerastes 



Figure 319,a 



Acerastes Cushman, 1929, Troc. U.S. Nat. Mus., vol. 74, art. 16, p. 53. Type: 

 Mesostenus periinax Cresson; original designation. 



Front wing 4.0 to 9.8 mm. long; body rather slender; frons unarmed; 

 clypeus moderately small, rather strongly convex, its apical 0.35 ± 

 abruptly declivous, its apical margin moderately convex, without a 

 median point; mesoscutum rather strongly convex, polished, its punc- 

 tures of moderate size, irregularly spaced, rather close anteriorly, 

 elsewhere sparser; notaulus sharp, deep, extending beyond middle of 

 mesoscutum; epomia strong, the upper margin of pronotum at its 

 dorsal end with a strong tubercle; propodeum moderately convex, its 

 basal carina sharp and complete, its apical carina represented by 

 sublateral tubercles that tend to be rounded in female, and often 

 crestlike in male; propodeal spiracle circular or short oval; areolet 

 very small, roughly pentagonal, the second intercubital absent or 

 vestigial; ramellus absent; nervulus a little basad of basal vein; base 

 of second discoidal cell narrowed to a point or almost so; mediella 

 strongly arched; nervellus broken below the middle; axillus close to 

 anal margin ; fu'st abdominal segment moderately slender, its spiracle 

 near its apical 0.40, without a subbasal lateral tooth and without 

 distinct longitudinal carinae; second tergite mat or subpolished, in 

 female its punctures small and sparse, separated by a little more than 

 the length of the hairs, in male the punctures denser; tergite 7 without 

 a median white spot; ovipositor sheath about 0.14 as long as front 

 wing; ovipositor moderately slender, with a long tapered point. 



Acerastes is a moderately large Neotropic genus. One of its more 

 widespread species enters southeastern United States. 



Figure 222. — Localities for 

 Acerastes pertinax. 



