a Family of the Hymenoptera Heterogyna. 325 



pressed plates very hairy at their apex and beneath, and the hori- 

 zontal piece which articulates at the base beneath the large valves 

 is here dilated into a broad lanceolate plate, deeply emarginate at 

 its apex. 



Sp. 1. Rhog. fimbriatus, Shuck. Length 174- lines. 



Expansion 22 lines. 



Helvolus, pilosus ; ahdomine glabra, segmento ultimo supra et duobus ul- 



timis subtus fimbiriatis ; capite, {clypeo antennis mandibuUsque casta- 



neis exceptis) nigro, nervis alarum brunneis et pedunculo abdominis 



transverso-quadrato, convexo, 



Rufo-testaceous very pilose upon the face, the thorax above and beneath the 

 coxae also beneath the peduncle of the abdomen, and the margins of the 

 terminal segment above and of the two last beneath, which are densely 

 fringed. The head black upon the vertex and behind, face convex, 

 sulcated in front of the anterior ocellus : the ocelli large, disposed in 

 an equilateral triangle on the vertex, with about the diameter of one 

 intervening between the anterior and posterior pair ; antennae slender, 

 setaceous, the scape one-fourth the length of the organ ; mandibles 

 broad, nearly triangular, very slightly curved, the inner edge acute. 



Thorax gibbous in front and at the scutellum, which is very pilose, pro- 

 thorax very distinct, and metathorax slightly produced and rounded 

 posteriorly ; wings subhyaline, their nervures robust and brown, the 

 radial lost in a large dilated dark patch at the commencement of the 

 marginal cell ; the cubital slightly undulated, the first recurrent in- 

 serted just beyond the middle of the first submarginal cell, and the se- 

 cond recurrent half way between the first and the termination of the 

 cell, and diverging obliquely towards the edge of the wing ; legs casta- 

 neous, the femora elongate, ovate, compressed, their outline slightly 

 rounded above and below. 



Abdomen opake, clavate, the peduncle transverse quadrate convex, fringed 

 at its apex and very pilose beneath, where it is slightly longitudinally 

 carinated, not so wide as the second segment, which viewed above is 

 nearly quadrate, the remainder all transverse : of these the penultimate 

 and terminal are the largest, the latter deeply emarginate in the middle, 

 fimbriated along the edge, as are also the two last ventral segments, 

 the terminal of which is semicircular and the penultimate nearly qua- 

 drate. In the collection of the British Museum, and in my own. 

 This remarkable insect is from the Gambia ; it is the largest of the 



family, and its generic description and the observations thereon will 



exhibit its distinction from all the rest of the family. 



Note upon Typhlopone. 



The preceding pages were at press when I discovered in the col- 

 lection of the British Museum an apterous insect from Sierra Leone, 



