XVII 



HUNTING DIPTERA 237 



paralysed by a sting, resist evaporation, and would 

 dry up in two or three weeks. Consider the slender 

 Sphaerophoria — the larva's first mouthful. What is 

 there in this body to evaporate ? An atom — a mere 

 nothing. The body is a thin strip — its two walls 

 touch. Could such prey form a basis for preserved 

 food when a few hours would evaporate its juices, 

 unrenewed by nutrition ? To say the least, it is 

 doubtful. 



Let us proceed to consider the manner of hunting, 

 by way of throwing a final light on the subject. In 

 prey withdrawn from the clasp of a Bembex, one 

 may not infrequently observe indications of a capture 

 made in haste, as best might be, in the chances of 

 a wild struggle. Sometimes the Dipteron has its 

 head turned backward, as if its neck had been 

 twisted, its wings are crumpled, and its hairs, if it 

 have any, are ruffled. I have seen one with the 

 body ripped open by a bite from the mandibles, and 

 legs lost in the battle. Usually, however, the prey 

 is intact. 



No matter. Considering that the game has 

 wings prompt in flight, the capture must be made 

 with a suddenness which it seems to me hardly allows 

 of obtaining paralysis without death. A Cerceris with 

 its heavy weevil, a Sphex engaged with a corpulent 

 grasshopper or a paunched ephippiger, an Ammo- 

 phila holding its caterpillar by the nape of its neck, 

 have all three the advantage over a prey too slow to 

 avoid attack. They may take their time, choose at 

 leisure the exact spot where the sting shall penetrate, 

 and, in short, can act with the precision of a physiolo- 

 gist who uses his scalpel on a patient laid upon the 



