a Family of the Hymenoptera Heterogyna. 265 



wliich we only know the males, and when 1 have also shown that 

 there are as many structural resemblances as might be expected, or 

 is usual between the opposite sexes of these anomalous groups, 

 surely it is not presumptuous to suppose, in the absence of positive 

 testimony, that these may be the sexes of the same genus. The 

 solitary point which still causes me at all to doubt it, is the minute 

 tooth beneath and within the apex of the claws of the males of the 

 genus Labidus, although it is scarcely obvious in the smaller species 

 of that genus ; therefore in these small females, which are much 

 smaller than the smallest males, this tooth may become obsolete. 

 The disparity of size in the sexes, I have before stated in the pre- 

 liminary observations, is no objection to the hypothesis. I proceed 

 accordingly to describe them as Labidi. 



Sp. 12. Lab. (1 Typhlopone) Kirbii, Shttck. Length of the head 1 line. 



Probable length 4^ lines. 

 Capite castaneo nitido punctulato, antice substdcato, viandibiUis badiis. 

 Head bright chestnut, shining, very slightly and loosely punctured j slightly 

 longitudinally channeled in front, but which terminates abruptly in a 

 small fossulet at about one- third the length of the head: without eyes 

 or ocelli. Mandibles dark pitchy chestnut, flagellum of the antennae 

 also obscure. 



In my own collection. 



Of this insect I have only the head, which is attached to the thigh 

 of a Formica; to judge from the size of this head and the comparative 

 proportion to the whole insect in other species, this would be the 

 largest. I dedicate it with much respect to the venerable promoter 

 of the science of Entomology in this country, whose Monographia 

 Apum Anglice will ever remain a standard of high perfection. 



Sp. 13. Lab. (2 Typhlopone) Curtisii, Shuck. 



Length about four lines. 

 Rufo-testaceus, glabratus ; capite punctidato, postice profunde sidcato ; 

 mandibidis badiis. 

 Reddish testaceous. Head brightly shining, punctulate, deeply sulcated 

 longitudinally in the centre behind, the channel terminating near the 

 centre of the head in a moderately large fossulet : without eyes or 

 ocelli ; mandibles pitchy-brown. 

 Thorax opake, more closely and deeply punctured than the head. 

 Abdomen brightly shining, very slightly punctured, the peduncle quadrate, 

 opake and convex, the third and fourth segments slightly constricted 

 at their base, the apex of the terminal segment abruptly truncated 

 and armed on each side with a minute spine. 



In the collection of the British Museum. 

 This insect is distinguished from the preceding by its smaller 

 size and by the deeper sulcation appearing only on the vertex. It 



