terminal segments of Aculeate Hymenoptera, 265 



Lithurgus. — The 7tli ventral segment in this peculiar 

 genus is simply rounded at the apex ; the 8th is widely 

 truncate ; the armature is extraordinarily small for the 

 size of the insect ; the stipites are large and swollen at 

 the base, and produced at the apex of each into a long 

 straight process ; sagittae wide at the base, then narrowed 

 to the apex, each with an apical dilatation (see PL XIII. , 

 fig. 17). 



Osmia. — Very variable as regards the number of ven- 

 tral segments exposed, and probably divisible into many 

 good subgenera ; 6th segment simply hairy ; 7th mem- 

 branous or nearly so ; 8th tongue-like, sometimes nar- 

 rowly emarginate at the apex ; armature with the 

 stipites without lacinifB, generally very straight and 

 elongate, curved or angularly bent inwards at the apex, 

 the apical portion more or less clothed with hairs, and 

 occasionally slightly dilated at the angle ; sagittse 

 straight or converging beyond the middle, sometimes 

 united by a membrane at the base (see PI. VIII., figs. 

 8—16). 



Anthocopa. — Same as Osmia, but 7th segment dis- 

 tinct. 



Meliturga. — 7th ventral segment with two apical bi- 

 dentate processes, united by only a very thin connection, 

 recurrent plates wide and straight ; 8th terminating in a 

 narrow process, widened into a spoon-like dilatation at 

 the apex ; armature with the stipites wide at the base ; 

 lacinia long, narrow, and pointed ; obliquely truncate, 

 viewed sideways ; sagittse short, blade-like, divergent at 

 the apex (see PI. XIII., fig. 10). 



Eucera and Tetralonia. — In these two genera .the style 

 of the apical segments and armature is almost similar ; 

 the 7th ventral segment is emarginate in the centre, and 

 is produced and raised at each anterior angle into two 

 or three tubercular processes ; the 8th is rather wide, 

 and more or less truncate at the apex ; armature stout, 

 with the stipites terminating in a long narrow lacinia, 

 often dilated at the apex ; sagittfe widely triangular 

 beyond the middle, and externally hamate (see PL X., 

 figs. 6—6h). 



Hahropoda, Anthoplwra, and Saropoda.—lih. ventral 

 segment with a more or less square apical plate, or pro- 

 duced at the apex into a variously-shaped process, rarely 

 simply truncate ; 8th short and usually five-sided ; the 

 apical margin often with two slight projections bearing 



