170 ANIMAL PARASITES AND MESSMATES, 



cuckoo acts with less cruelty, since she is contented to 

 lay her eggs by the side of those which occupy the nest. 



Bemarkable examples of the refinement of cruelty 

 and of gluttony are to be found in this little animal 

 world. It is not enough that some among them feed 

 on the entrails of their young neighbours; there are 

 wasps which, in order to make the agony last longer, 

 place by the side of the eggs which they lay, chloro- 

 formed flies, which wait patiently for the time when 

 they can yield themselves up, still palpitating, to these 

 young tyrants. The days, the hours, perhaps even the 

 minutes, are scrupulously reckoned for the preparation 

 of this living morsel. As the process of hatching pro- 

 ceeds, the repast acquires properties more and more 

 adapted to the age of the young wasps. 



The Sphex is not less cruel. Some of the insects 

 which are found in South America attack, not the 

 young ones, but those which are grown up, and snatch 

 spiders from their webs as slave-hunters carry off 

 negroes from the wood;- they garotte them, and cram 

 them into narrow cells, after having chloroformed them 

 to preserve them more effectually. These spiders, retain- 

 ing enough life not to lose their nutritious qualities, 

 become the easy prey of the larvae of the Sphex. The 

 mother of these hymenoptera takes care to deposit her 

 eggs, as well as the living booty, in such a manner that 

 the larvae, at the moment of being hatched, live in abund- 

 ance. These young larvse, white and without feet, are 

 dainty enough to reject any other kind of food. This 

 is an act of cruelty which resembles that of the 

 ichneumon, to which it may well be compared. 



The Platygasters, another kind of hymenopterous 



