( cxxxvii ) 



to massage it systematically with bier mandibles from end 

 to end, passing from tail to head. Twice she left off for a 

 moment to push her face along the dusty ground, as if to 

 clean her mandibles from something that soiled them, although 

 she certainly had not broken the skin of the larva. 1 have 

 never seen a Fcssor do this before. Eventually she put the 

 larva down with its head at the margin of the burrow, went 

 down backwards, seized the larva by the neck and dragged 

 it down, came out, went down and came up again with a 

 little more earth, did this twice again, and then dragged 

 down the larva which I had seen her bring in. My attempt 

 to bottle her failed. I had no net with me, and as I was 

 due at the hospital for the evening round I couldn't wait 

 for her return. But I'm sure she was of the same species 

 as the last. It's interesting that she was using two medium- 

 sized larvae instead of one larger specimen. 



" Courtship of Diptera. —The courtship of Asilidae which I 

 have witnessed several times is an interesting performance. 

 The species referred to was almost certainly a Promachus. 

 The $ sits as usual on a prominent bare twig, and the c? 

 hovers in the air like a Syrphid, a few inches away on her 

 right or left front and a little above. His energies are appar- 

 ently directed to pleasing the lady by his hum : the pitch 

 gradually rises, and as it does so he no longer remains 

 stationary but oscillates slightly up and down, and then, 

 just as the situation gets very exciting, the $ suddenly dashes 

 away and the <J after her. Sometimes she settles again and 

 the whole process is repeated, but I have never seen the 

 actual union. One very often sees pairs united end to end : 

 at other times the <$ is on the back of the ?, who often has 

 her proboscis embedded in some prey [see Trans. Ent. Soc, 

 1906, pp. 366-68], but whether the latter position is previous 

 or subsequent to the former T do not know. 



" In another group of flies, Bombyliidae, the <J also en- 

 deavours to please by his hum : in this case 1 have caught 

 a, specimen for identification [a Exoprosopa eluta, Lw.J. 

 On Now 29th 1 first saw this. It is a species which keeps 

 close to the ground, on which it often settles. On this occa- 

 sion 1 saw one, presumably the ., sitting on the ground 



