British Hymenoptera. 225 



? . Very like the 3" , but with the face unspotted, and the apex 

 of the abdomen simply pointed, not inflexed ; the 6th segment 

 above rugose and slightly carinated. Length, 6 — 7 mm. 



Hab. Folkestone ; Charlton ; Birch and Darenth 

 Woods ; Weybridge ; S. Devon. Hybernates in dead 

 bramble-stems {F. Smith). 



PSITHYRUS, Lep. 



Lep., Ann. Soc. Ent. Fr., ii. (1832) = Apathus, New- 

 man. 



Wings with three submai'ginal cells ; labial palpi 4-jointed, maxil- 

 lary palpi 2-jointed ; $ with the mandibles not fringed with curled 

 hairs, as in the genus Bomhus, and with the posterior tibiae out- 

 wardly convex, dull, and hairy; J without any corbicula to the 

 posterior tibi«, which are outwardly convex, dull, and hairy, like 

 those of the <? ; basal joint of posterior tarsi simple. 



A genus of parasitic bees living in the nests of species 

 of Bomhus, and often resembling them so closely in 

 colour, &c., as to be distinguishable only by the generic 

 characters given above. 



(2) 1. 4th and following segments of the abdomen red in 



both sexes . . . . . . . . . . . . rupestris. 



(1) 2. 4th and following segments of the abdomen either 

 white or yellow, or of various colours, but not 

 all red. 



(4) 3. ^ with the abdomen subglobose, the extreme apex 



fulvous ; 5 with the extreme apex of the abdo- 

 men beneath armed with a pointed process . . quadricolor. 



(3) 4. (^ with the abdomen subtriangular, its extreme 



&])ex black ; 2 with the apex simple. 



(6) 5. Both sexes with the posterior metatarsi almost as 



wide as the tibi.ne, and generally with a line of 

 yellow pubescence dividing the black of the base 

 of the abdomen from the white of the ajDex ; ^ 

 with the sagittffi of the genital armature not 

 toothed beneath . . . . . . . . . . vestalis. 



(5) 6. Posterior metatarsi much narrower than the tibife, 



no yellow line of pubescence between the black 

 and white ; ^ sagitta; dentate beneath. 

 (8) 7. Apical segments of ^ black or yellow, not white ; 

 6th segment beneath simple, squamaa of the 

 genital armature widely triangular ; 2 with the 

 apex of the abdomen yellow at the sides, 6th 

 segment shining at the base . . . . . . canipe.^tris. 



(7) 8. Apical segments of ^ white, 6th segment beneath 



with a distinct callosity on each side, squamro 

 of genital armature narrowly triangular ; J with 

 the apex white, the 6th segment rugosely punc- 

 tured . . . . . . . . . . . . BarhuteUna, 



