Families Bethylid^e and Rliopalosomidse. 107 



broad depression ; scutellum witli a deep transverse sulcus 

 at the base. Median segment nearly half as long again as 

 broad, margined at the sides and at the apex, very tinely and 

 closely transversely striated, with five longitudinal carinoe, 

 the median one reaching the apex, the two lateral extending 

 beyond the middle, the two intermediate not reaching the 

 middle ; the sides of the segment and the surface of the apical 

 truncation almost smooth. Abdomen shining, the fifth and 

 sixth dorsal segments with scattered punctures. Fore wing 

 with the medius short, which causes the basal nervure and 

 the nervulus to meet at an acute angle, forming two sides of 

 an equilateral triangle ; stigma small ; radius long. 



Hab. British East Africa, Voi, 1800 ft. (S. A. Neave), 

 March 21-23, 1911. 



Family RhopalosomidaB. 



Genus Olixon, Cam. 



Olixon, Cam. Biol. Centr.-Amer., Hymen, i. p. 412 (1887). 

 Saphobethylus, Kieff. Ann. Soc. Sci. Bruxelles, xxxv. p. 216 (1911). 



Type of the genus, 0. testaceum, Cam. 



Saphohethylus pallidus^ Kieff., is a synonym of Olixon 

 testaceum. 



Cameron places this genus in the Braconidae, expressing 

 strong doubt as to the true relationship of the genus, and 

 noticing a general resemblance to the Bethylidje. Kieffer 

 places it in the Bethylidse without comment on the abnormal 

 characters. The antennae are 13-jointed in the male, 12- 

 jointed in the female, very long and slender, agreeing well 

 with Rhopalosoma, with which the genitalia of the male also 

 show close affinities. It differs from that genus in the entire 

 eyes, in the absence of ocelli, in the rudimentary wings, and 

 in the subsessile abdomen. The tarsi of the female do not 

 show strongly broadened joints as in Rhopalosoma. Though 

 these differences remove Olixon from very close relationship 

 with Rhopalosoma, it seems to be sufficiently near to be 

 placed in the same family. With regard to the afiinities of 

 the family, it must be pointed out that tlie genitalia show 

 a very distinct relationship to those of the Eumenidge and 

 differ strongly from those of all other Hymenoptera. Thus, 

 of the many attempts to assign a place to the group, that of 

 Westwood, who connects it with the Vespidse, is the most 

 correct. It is almost certainly derived from the same stock 

 as the Eumenidse, but strongly modified by nocturnal and 



