92 ICHNEDMONID^. 



This very distinct genus may be known by the transversely 

 rugose thorax, somewhat relating it to the XOEIDIDES, between 

 which and Coleocentrus it would appear, as is pointed out by 

 Thomson (Opusc. Ent. p. 737), to form a transitional group of 

 species. Its European representatives are very well known to 

 prey upon the large wood wasps, of the family SiuiciDvE, and 

 doubtless their Indian relations follow a similar means of livelihood; 

 in fact, Mr. E. P. Stebbing tells us (Journ. Bombay Nat. Hist. 

 Soc. xvi, p. 684) that both Thalessa and Rhyssa attack wood- 

 feeding grubs in India, though I have seen and heard of no 

 representatives of the former genus thence. He does not, 

 however, state that these grubs are the larvae of Sirfx, but I have 

 seeu females ot' the latter, differing from the Palaearctic Sirex 

 gigas, L., only in having the prothorax ferruginous and the hind 

 tibiae partly black, in the collection of Mr. Ernest Elliott, from 

 Haidnrabad, in Berar ; and three kinds of Xipliydria have already 

 been found in India (c/. Spolia Zeylanica, 1905, p. 71). The 

 Linnean Sirex has been noticed by Eadoszkovsky (Horae Ent. viii, 

 p. 200) as far east as the Caspian Sea ; and the genus is known 

 to be very widely distributed. 



49. Rhyssa persuasoria, L. 



Ichneumon persuasorws, Linnaeus, Faun. Suec. p. 400; Donovan, 

 Brit. Ins. xv, p. 522($). 



Pimpla persuasoria, Fabric-ills, Syst. Piez. 1804, p. 112. 



lihussa persuasoria, Gravenhorat, Ichn. Eur. iii, 1829, p. 267 ; 

 Holmgren, Sv. Ak. Ilandl. 1860, no. 10, p. 9 ; Taschenberg, Zeit. 

 Ges. Nat. 1863, p. 251 ; Vollenhoven, Pinac. pi. xi, n'gs. 5, 6- 

 (<?$) 



Head laterally intumescent and as broad as the eyes, frons and 

 face subglabrous ; epistoma deplanate, clypeus narrow and 

 centrally obtusely produced; palpi and all the orbits more or less 

 white, though sometimes immaculate on the vertex ; tf with 

 the face also entirely white. Antennce filiform, shorter than 

 body, scape black ; flagellum generally dull ferruginous beneath 

 or even entirely, with the joints elongate, apically nodulose 

 and the basal one distinctly curved. Tliorax subcylindrical, 

 black; metanotum centrally canaliculate; propleural marks, 

 pronotum broadly in front, a line before and a callosity beneath 

 radix, a mark above the intermediate coxae and another above the 

 hind ones, which latter sometimes coalesce across the apex of 

 the metathorax, white. Scutettum and postscutellum entirely or 

 apically white ; very rarely black. Abdomen quite twice as long 

 as head and thorax, cylindrical and about as broad as the latter, 

 in $ laterally subcoin pressed ; basal segment gradually constricted^ 

 of cJ thrice as long as broad, glabrous and centrally sulcate ; one 

 or two basal segments apically, and laterally towards the apex, 

 white ; second or third to seventh with lateral and infra-apical 

 spots on either side more or less broadly white; terebra nearly a 



