1903 Fossorial Hymcnoptera 35 



way entirely different from that adopted by any other species 

 that I know. Instead of entering the burrow tail first and 

 holding the prey in her jaws, Oxybelus goes in head first 

 and drags the fly along behind her, her sting being used as 

 the means of attaching the burden to her body. The fly is 

 thrown on its back and the sting plunged into the ventral 

 surface of the thorax rather far back (somewhere near where 

 I should judge the centre of gravity of the fly to be 

 situated) ; the head of the fly is forward. Thus the ventral 

 surface of the fly is close against that of its captor, the 

 head comes under her waist while the abdomen projects 

 behind and brings up the rear of this procession of two. As 

 far as I have been able to see, the Oxybelus makes no use of 

 her legs in steadying her load and keeping it straight, but 

 there are certain strong hairs on the ventral surface of the 

 abdominal segments which, I fancy, prevent the fly from 

 slewing round to right or left. When she has disengaged 

 herself of her spoil the little fly-catcher turns round in her 

 burrow, for she always comes out head first. On gaining 

 the doorway she carefully scratches the soil over the entry 

 before starting on another foray, and this she does invariably 

 even though she returns with a fresh fly in less than a minute, 

 if there be good luck to her hunting. This manoeuvre is 

 probably to guard against the intrusion of ants and of in- 

 quiline Hymenoptera, who play the cuckoo among insects. 



I trust that without going into the minutiae of structure I 

 have succeeded in giving some idea of the features that serve 

 as the basis of classification of this group of insects, and have 

 conveyed, in suggestion at anyrate, what points may be of 

 generic or specific value. Be this as it may, the chief in- 

 terest of these animals lies in their domestic economy and 

 the adaptations of structure to individual specific habits ; 

 and here, as I have already pointed out, there is room and 

 need for much delightful work on the part of those with 

 seeing eyes. 



