vii BOMBYLIIDAE 487 



being scarcely a twentieth of an inch long and very slender ; it 

 is, however, provided with a deflexed horny head, armed in front 

 with some stiff bristles, while on the under surface of the body 

 there are four pairs of elongate setae serving as organs of loco- 

 motion : thus endowed, the frail creature hunts about the sur- 

 face of the masonry, seeking to find an entrance ; frequently it 

 is a long time before it is successful ; but though it has never 

 taken any food it is possessed of great powers of endurance. 

 Usually, after being disclosed from the egg, it remains about 

 fifteen days without stirring ; and even after it commences its 

 attempts to enter the nest it is still capable of a long life without 

 taking any food. Possibly its organisation will not permit it to 

 feed (supposing any food were obtainable by it) without its 

 growing somewhat thereafter, and if so, its chance of obtaining 

 entrance through the masonry would be diminished. Abstention, 

 it would appear, is the best policy, whether inevitable or not ; 

 so the starving little larva continues its endeavours to find a 

 chink of entrance to the food contained in the interior of the 

 masonry. It has plenty of time for this, because it is better for 

 it not to get into the cell of the bee until the grub is quite full 

 grown, and is about to assume the pupal form, when it is quite 

 incapable of self-defence. Finally, after greater or less delay, 

 the persevering little larva succeeds in finding some tiny gap in 

 the masonry through which it can force itself. M. Fabre says 

 that the root of a plant is not more persistent in descending 

 into the soil that is to support it than is this little Anthrax 

 in insinuating itself through some crack that may admit it to its 

 food. Having once effected an entrance the organisation that 

 has enabled it to do so is useless ; this primary form of the larva 

 has, in fact, as its sole object to enable the creature to penetrate to 

 its food. Having penetrated, it undergoes a complete change of 

 form, and appears as a creature specially fitted for feeding on the 

 quiescent larva of the bee without destroying it. To accomplish 

 this requires an extreme delicacy of organisation and instinct ; 

 to bite the prey would be to kill it, and if this were done, the 

 Anthrax would, Fabre supposes, ensure its own death, for it 

 cannot feed on the dead and putrefying grub ; accordingly, the 

 part of its body that does duty as a mouth is merely a delicate 

 sucker which it applies to the skin of the Ckalicodoma-grnb ; 

 and thus without inflicting any perceptible wound it sucks day 



