Parasites and Predators 



see if her sting has done its work is a sight that must 

 interest every naturalist. She climbs down from her 

 position on the back of the beetle larva ; then she proceeds 

 to pull its legs, in turn, and also various parts of its hairy- 

 covering. To satisfy the wasp, her victim must exhibit no 

 sign of life. And the reason is not far to seek. 



We mentioned that certain solitary wasps were in the 

 habit of producing paralysis in their victims before they 

 laid their eggs upon them : this little black wasp affords 

 a parallel case. Should the beetle grub be killed outright, 

 it would putrefy in a very short time ; should it not be 

 paralysed, it would continue to grow, and a growing insect 

 sheds its coat from time to time, a happening that would 

 be fatal to the parasite's projects. Satisfied that her 

 victim is reduced to a sufficiently comatose state, the 

 wasp will reduce grub after grub to a state of inertia. Far 

 more grubs are put out of count than ever the wasp can 

 utilise. 



Returning after her labours to her first victim, she again 

 inserts her sting in the very spot where she first punctured 

 the grub's skin ; in doing so she enlarges the first-formed 

 hole. Around this hole she carefully deposits from one 

 to six semi-opaque eggs, in such a position that, when her 

 larvae hatch, their heads will all be turned towards the 

 wound she has made. 



On hatching, the pale yellow larvae all apply their heads 

 to the cavity formed by their mother and suck the juices 

 of their victim in no uncertain manner. Six hungry grubs, 

 all imbibing vital fluids continuously, soon reduce the beetle 

 larva to the condition of a shrivelled husk. This mere 

 shell, however, still has its uses, for the wasp grubs crawl 

 within it for shelter, preparatory to spinning their cocoons. 



There are a very large number of these insect parasites. 

 In general habits they are very like the wasp we have just 

 described, and most of them also are closely related to the 

 wasps and bees. In one case matters are cut so fine that 

 if all the parasitic grubs do not grow at the same rate 



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