132 WHITE BUTTERFLIES 



its own cocoon beside the dying caterpillar, which 

 never survives the ordeal, though it betrayed no 

 symptoms of discomfort or illness so long as it could 

 go on feeding. 



Most country dwellers must be familiar with the 

 ichneumon cocoons a pile about as big as a hazel 

 nut of bright yellow, silky objects, oval in shape, each 

 about the size of a canary seed. It is to be feared that 

 these little golden treasure-heaps are often destroyed 

 by careful gardeners in the belief that they are the 

 eggs of the butterfly or some other mischievous insect. 

 It is a grievous mistake. The white butterfly's eggs 

 may be found on the under-sides of cabbage leaves. 

 They are dull yellow, set on their ends and neatly 

 arranged in groups of fifty or more. No mercy should 

 be shown them. 



The credit of tracing out the true procedure of 

 Apanteles is due to that most industrious and original 

 naturalist, the late J. H. Fabre. In his own inimitable 

 way he has described how he arrived at an estimate of 

 the extent of the service rendered to economic horti- 

 culture by these diminutive flies. He reared several 

 hundreds of the caterpillars, whereof no less than 

 seventy-five per cent. three out of every four proved 

 to be infested by the parasitic grubs, and died in the 

 act of preparing for metamorphosis. 



