204 HYMENOPTERA ACULEATA. 



closely resembles Sj-iheeodes, and except for the form of its 

 tongue, which has the sides slightly sinuate, and the more 

 transverse labrum, the description of the mouth parts of 

 Sphecodes will apply equally well to this genus. The 

 antennae in the ^ are long as in Sphecodes, but the joints 

 are simple, not moniliform, those of the ? are short and 

 simple. The c? is nearly always narrow and elongate in 

 form, with cylindrical abdomen, the ? much wider and 

 more robust, six ventral segments are exposed in the S, five 

 in the ? , the fifth dorsal segment in the latter sex bears a 

 longitudinal ridge or vima, the sixth being almost hidden 

 beneath the fifth ; these characters of the fifth and sixth 

 segments are peculiar to this genus, so far as the British 

 fauna is concerned. The form of the armature of the (J is 

 often very valuable as a help in determining the species, 

 although it is not of such value as in Sphecodes, and in 

 some species is scarcely characteristic ; the armatures of 

 all the British species are figured in Trans. Ent. Soc. 

 1882, pi. 8-9. The most important characters seem to lie in 

 the shape of the face and propodeum, and the sculpture and 

 punctui-ation of the different parts of the insect; in some 

 species there is a row of fine spines along the underside of 

 intermediate femora, and the calcaria in some are beautifully 

 serrate ; the poUinigerous hairs are borne on the tibiae, 

 which in the $ are also furnished with a patella at the base, 

 and the underside of the femora, coxae, and trochanters. 

 The various species burrow in banks or sandy places, or 

 even sometimes in hard footpaths, ol'ten forming large 

 colonies, their burrows are branched ; in times of ap- 

 pearance, &c., they resemble Sphecodes. Mr. R. C. L. 

 Perkins has given a great deal of attention to their habits, 

 and has studied their burrows, &c., with great care; he is 

 convinced that the new females retire at once to their 

 burrows after impregnation, which he thinks often 

 takes place in the burrow itself, and that only a few 

 stragglers are found at any distance from them, the males 



