SERPHOID AND CHALCIDOID PARASITES OF THE HESSIAN FLY HI 



neck, without a median carina but with the lateral folds usually distinct, the 

 spiracles small and elliptical, the whole surface of propodeum reticulate- 

 punctate, this sculpture a little stronger medially than laterally ; pleura less 

 strongly sculptured than the dorsum. Legs normal. Fore wings extending to 

 the apex of abdomen or a little beyond the apex; submarginal vein a little 

 longer than the marginal and postmarginal and two and one half to three 

 times as long as stigmal; wing bare from base to apex of submarginal vein, 

 this bare area prolonged somewhat under the marginal vein and along the 

 posterior margin ; ventral surface of wing with eight or nine long hairs in a 

 row behind and paralleling the marginal vein ; marginal cilia short ; hind 

 wing not bare basally, nearly uniformly but rather sparsely ciliated over 

 the whole surface, its marginal cilia not over one fourth as long as the greatest 

 width of wing. Abdomen about as long as thorax, pointed ovate, with a short 

 petiole which is attached beneath the propodeal neck ; first and second tergites 

 beyond the petiole large and subequal, together comprising nearly two thirds 

 of length of abdomen ; entire abdomen smooth and polished ; ovipositor sheaths 

 slightly exposed at apex. 



Color of head and thorax dark, metallic green; abdomen blackish with a 

 large, more or less rounded spot, which usually embraces most of the first and 

 second tergites except their margins, yellowish testaceous ; mandibles testa- 

 ceous ; antennal flagellum dark brownish or blackish, the scape and pedicel 

 usually more or less brownish but frequently mostly pale testaceous; legs, 

 including all coxae, pale testaceous ; wings hyaline, the venation brownish 

 testaceous. The yellowish marking on abdomen is variable, sometimes nearly 

 absent, in other instances embracing most of the abdomen. 



Male. — Length 1.2 to 2 mm. Similar to the female except that the antennal 

 club is not prolonged into a slender process at apex, the first ring joint is 

 smaller than in the female, the scape and pedicel are nearly always testaceous, 

 and the abdomen is more distinctly petiolate, the petiole as long as broad, the 

 body of abdomen short, about as long as broad, and yellowish except at 

 apex. 



Kedescribed from specimens reared from the hessian fly in North 

 America and also several specimens from Europe. 



REVIEW OF LITERATURE 



The genus Callitula was described by Spinola in 1811 in a generic 

 key and bicolor named as the only included species, without further 

 description and without indication of the locality from which his 

 specimens came. In 1833 Walker described Micromelus rufomacu- 

 latus from specimens collected on grass in the vicinity of London. 

 The following year Pteromalus plagiatus was described by Nees 

 from specimens taken near Sickershausen and Carlsruhe, Germany, 

 and Callitula bicolor Spinola was cited as a synonym. Westwood, 

 in 1840, redescribecl Micromelus rufomaculatus in his Introduction 

 to the Modern Classification of Insects, and Blanchard also pub- 

 lished a short description of it and stated that it was found near 

 Paris and London. In 1856 Foerster proposed the generic name 

 Baeotomus to replace Micromelus Walker which Foerster considered 

 to be preoccupied by Micromelum Blume, a botanical name. Al- 

 though this change was unnecessary and contrary to the present 

 code of nomenclature, it was accepted by several subsequent authors 

 and accounts for the later use by some of them of the combination 

 Baeotomus rufomaculatus. In 1858 Keinhard stated that Microm- 

 elus rufomaculatus Walker and Pteromalus plagiatus Nees were the 

 same species ; at the same time he mentioned the fact that Callitula 

 bicolor Spinola had been treated as a synonym by Nees but indi- 

 cated that he considered this a manuscript name only. In 1878 

 Thomson redescribed the species under the name Baeotomus plagia- 



