Two new Strepsipterous Insects. 47 



cephalo-thoracic caps of the pupa cases from which winged males 

 may he obtained. The latter exhibit also a transversely carinated 

 apex, furnished with three small equidistant basal rugosities above, 

 two others, somewhat larger and wider apart, being seen upon a 

 parallel line lower down, when viewed in front; the occipital sum- 

 mit being traversed by a faint sutural line, where this capsule or 

 operculum eventually separates, being thrown off as a mask on the 

 exit of the perfect insect. The apod female, moreover, is not de- 

 void of certain additional discriminative characters, wherein, how- 

 ever, the condition of the cephalo-thorax appears to be subject to 

 considerable modification; which (whether depending upon gene- 

 ric, specific, or metamorphotic distinctions) a comparison between 

 the figures and descriptions of this part in the Xenos Rossii, as 

 given by Dr. Siebold, — in the Slylops aterrima, by Mr. Newport, 

 — and in these parasites on Hylceus, — may serve to exemplify. 



In this latter sex also a small glossy distension towards the 

 anterior portion of the cephalo-thoracic region, is observable on 

 each side, and dark protuberances at the basal angles, corre- 

 sponding apparently with others more prominently developed in 

 the pupa-cases of males, and analogous to those noticed in other 

 instances by different observers.* 



With respect to these several markings and protuberances, 

 the question naturally suggests itself, to what corresponding 

 organs they may respectively be referred, regard being had also 

 to the very limited portion of the cephalo-thoracical region 

 strictly attributable to the head itself, according to the relative 

 distribution which has been ascribed to the larva-segments. This 

 brings me to notice a remarkable circumstance to which Dr. 

 Siebold has directed attention,-}- namely, " that the feet of the pupa 

 lie," as he states, "always and ab initio beneath that surface of the 

 pupa-case which is turned away from the ventral region of the 

 stylopized Hymenopterous insect ; . . . whence it is to be understood 

 that the convex surface of the cephalo-thorax" (as represented in 

 his figures) is the ventral, and the concave, the dorsal region;" 

 and, furthermore, that he had " likewise always distinctly ob- 

 served, when the males of Xenos Rossii were on the point of 

 issuing, after the operculum of the pupa-case had been cast off", 

 that they had both their face and their feet turned away from the 



* See the figures of supposed larvse with exserted heads, as represented by Mr. 

 Curtis (Brit. Ent. pi. 226, fig. B.) ; by Mr. Westwood (Trans. Ent. Soc. vol. i. 

 pi. 17, fig. 9, 10, 12) ; by M. Leon Dufour (Ann. Sci. Nat. torn. 7, 1837, pi. 1. 

 fig. 15, &c). 



f Loc. cit. p. 152. 



