196 Eev. T. A. Marshall's monograph of 



The species is recorded by Van Vollenhoven as a parasite 

 of Depressaria applana, Fab., and D. choerophylli, Zell. ; 

 and, by Eatzeburg, of D. nervosa, Haw. Bred by 

 Bignell out of Noctua triangulum, Hufn., and Xylina 

 ornithopuSy Eott. Mesochorus fuscicornis, Brischke, is its 

 hyperparasite. 



4. Macrocentrus inilrmus, Nees. 



Rogas infirmus, Nees, Mon., i., 203, $ ; Wesm., Nouv. 



Mem. Ac. Brux., 1835, p. 178, and 1838, p. 151 ; 



M. infirmus, Hal., Ent. Mag., iii., 139, <? ? . 

 Black ; palpi pale testaceous, the maxillary short, not longer 

 than the head ; mandibles testaceous. Head subdepressed ; face 

 short, very broad, transverse. Antennae fuscous, vv^ith the base of 

 the flagellum testaceous ; shorter than in spp. 1 — 3 ; in the $ 

 rather stout, shorter than the body, 30 — 33-jointed; in the ^ 87- 

 jointed, longer than the body. Mesothorax less gibbous than in 

 the others, its sutures pmictulate ; metathorax not shining, granu- 

 lated. Wings dull hyaline ; stigma fuscous, pale at the base ; 

 nervures fuscous ; radix and squamulae dull stramineous ; 2d 

 abscissa of the radius as long as the 1st intercubital nervure. 

 Legs shorter and stouter than in any other species ; pale testaceous, 

 femora and tibiae generally infuscated towards the apex ; hind coxas 

 sometimes fuscous at the base ; femora subclavate. Abdomen 

 linear, segments 1 — 2 and base of 3 very faintly and partially 

 aciculated, hardly less shining than the rest ; 1st segment oblong, 

 not narrowed at the base, obsoletely canaliculated ; tubercles 

 obtuse ; 2d margined laterally at the base ; belly pale at the base. 

 ^ similar ; antennae longer, entirely black ; palpi obscure ; abdo- 

 nainal segments 1 — 3 almost smooth ; 1st segment attenuated at 

 the base ; tubercles more acute ; legs dull rufous, coxae and femora 

 at the apex more broadly infuscated. Sometimes the antennae and 

 legs are more slender, approaching the structure of the next 

 species, but the wings remain distinct. Length, 1^ — 2J ; wings, 

 2|— 4 lin. 



Common ; a gregarious parasite. Bignell bred 2 

 females from Eupoc.cilia curvistrigana, Wilk. ; and 172, 

 all females, from a single caterpillar of Hydroecia 

 petasitis, Doubled., on Sept. 9th; at the time when he 

 communicated this fact to me all the parasites were not 

 disclosed. I have frequently captured both sexes. 



