CAREFUL MOTHERS 



rule their lives are too short to permit of their surviving until their 

 eggs are hatched. Nature has therefore devised a way out of the 

 difficulty; the mother must not kill her prey, but must see to it 

 that her larva can live on the victim, on emerging from the egg, 

 without being endangered by it. She therefore sinks her ovipositor 

 into a living caterpillar, and the larva, hatching out inside the 

 caterpillar's body, eats first the fat and flesh, and respects the vital 

 organs. The caterpillar lives on, and passes through various moults, 

 and only just before pupation does it collapse, an empty skin. But 

 now the larvae have completed their development, and can pupate 

 in their cocoons beside the husks of their victims. 



I made the acquaintance of several of the Ichneumon-wasps of 

 Brazil while I was breeding the Rosy Caterpillar; and it occurred 

 to me to note which species of this most dreaded enemy of the cater- 

 pillars had already adapted itself to the Cotton-grubs, in order 

 that I might inquire how the multiplication of these Ichneumons 

 could be assisted. In my gauze-covered breeding cages some tiny 

 black Ichneumons crept out from among the caterpillars, and also 

 a larger species with a striped abdomen. There are Ichneumons of 

 various forms and sizes in Brazil, and according to the nature of their 

 victims, their ovipositors are longer or shorter. Many species have 

 an ovipositor the length of one's finger, and these have usually 

 adapted themselves to the exploitation of larvae which live in wood. 

 We can only wonder how the Ichneumon contrives to locate her 

 victim through the thickness of the wood, and by means of her 

 thread-like ovipositor to bore through the bark and wood with 

 such accuracy that it enters the caterpillar's gallery just at the right 

 spot, and sinks into the body. 



The Bronze Wasps also provide their larvae with living nourish- 

 ment : these are the insects whose bronze-green, red and blue body- 

 colouring delights the lover of Nature in Brazil. These wasps fasten 

 their eggs to their victim; the emerging grubs then bore their way 

 into the caterpillar. 



The same end — namely, the provision of fresh meat for the brood^ 

 is attained by another race of insects by other means. While the 

 Ichneumons carry their eggs to their victims, the Hunting-wasps 

 carry their prey to their eggs, which are usually laid in burrows. 

 In order that the victim shall not die and dry up or putrefy before 

 the larva emerges, only a little poison is introduced by the sting, 

 so that the creature does not die, but lives on paralysed. Incapable 

 of escaping, or of defending itself, or of doing more than feebly 



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