170 FABRE'S BOOK OF INSECTS 



some, no less plentiful, in which the withered larva is accom- 

 panied by a family of little grubs wriggling uneasily round it. 



It is easy to see that a tragedy is happening under the 

 cover of the cocoon. The flabby, faded larva is the Mason- 

 bee's. A month ago, in June, having finished its ration of 

 honey, it wove itself a silken sheath in which to take the long 

 sleep that precedes its transformation. It was bulging with 

 fat, and was a rich and defenceless morsel for any enemy that 

 could reach it. And enemies did reach it. In spite of obstacles 

 that might well seem insurmountable, the wall of mortar and 

 the dome-shaped cover, the enemy grubs appeared in the secret 

 retreat, and began to eat the sleeper. Three different species take 

 part in this murderous work, often in the same nest, in adjoining 

 cells. We will concern ourselves only with the Anthrax Fly. 



The grub, when it ha< eaten its victim and is left alone in 

 the Mason-bee's cocoon, is a naked worm, smooth, legless, 

 and blind. It is creamy-white, and each of its segments or 

 divisions forms a perfect ring, very much curved when at rest, 

 but almost straight when disturbed. Including the head I 

 can count thirteen segments, well marked in the middle of the 

 body, but in the fore-part difficult to distinguish. The white, 

 soft head shows no sign of any mouth, and is no bigger than a 

 tiny pin's head. The grub has four pale red stigmata, or 

 openings through which to breathe, two in front and two 

 behind, as is the rule among Flies. It has no walking-apparatus 

 whatever ; it is absolutely incapable of shifting its position. 

 If I disturb its rest, it curves and straightens itself alternately, 

 tossing about violently where it lies ; but it does not manage 

 to progress. 



But the most interesting point about the grub of the Anthrax 

 is its manner of eating. A most unexpected fact attracts our 

 attention : the curious ease with which this larva leaves and 

 returns to the Bee-grub on which it is feeding. After watch- 

 ing flesh-eating grubs at hundreds and hundreds of meals, I 

 suddenly find myself confronted with a manner of eating that 

 is entirely unlike anything I ever saw before. 



