348 HYMENOPTERA ACULEATA. 



branches at its base, its apex produced into a variably 

 shaped plate, eighth short, subtruncate at the apex, arma- 

 ture stout, variable in form, the sagittaj wide and triangular, 

 deeply excavated near the base of their inner margin ; 

 iutermediate legs of the S much modified in some of the 

 species, posterior metatarsi of the ? outwardly dilated and 

 produced almost to the apex of the second tarsal joint, 

 truncate apically and fringed with hairs, posterior tibiae 

 with a dense pollinigerous scopa. The four British species 

 may be distinguished thus : — 



(4) 1. Basal joint of intermediate tarsi in the 



J" with a dense pencil of black hairs ; 



hairs of the ? entirely black except on 



the scopse. 

 (3) 2. All the joints of the intermediate tarsi 



in the S ^ith very long hairs, ? with 



the calcaria black . . _ . . pilipes. 

 (2) 3. (J, intermediate tarsi not longly ciliated, 



? calcaria pale reiusa. 



(1) 4. Basal joint of intermediate tarsi in the 



cj simple ; ? , hairs not entirely black. 

 (6) 5. Abdomen without distinct transverse 



pale bands ftjrcata. 



(5) 6. Abdomen with distinct transverse pale 



bands quadkimacitiata. 



A. retusa, Linn, {Hmvorthana, Kirh.). — Head and 

 thorax black, clothed in the S with bright fulvous hairs, 

 in the ? with black, face in the S with paler hairs, centre 

 of the mesonotum with black, labrum, sides of the face, 

 scape of the antennte in front and clypeus white in the ^, 

 the last of these narrowly black at the apex and broadly 

 at the base, ? with the two mandibular teeth subequal and 

 rounded ; thorax rather closely punctured, wings slightly 

 dusky ; abdomen black exceedingly finely and closely 

 punctured, S with the basal segment and sometimes also 

 the second clothed with long fulvous hairs like those of the 

 thorax, the rest with black, sometimes the second segment 

 is clothed with black hairs and has only an apical band of 

 fulvous, the other segments also have sometimes slightly 

 paler apical bands, abdomen ia the ? entirely clothed 



