26o 



Marvels of Insect Life. 



case which is enlarged as the caterpillar grows. It is slung up hammock-fashion 

 by silk threads at each end ; and the caterpillar protrudes sufficiently to reach 

 neighbouring leaves, but withdraws entirely when it suspects danger from exposure. 

 No caterpillars of any other genus construct their cases after this fashion, so that 

 the species may be at once identified by its hammock. 



Insect Ichneumons. 



Naturalists have borrowed the name of the ichneumon — a kind of mungoose 

 that keeps down the numbers of crocodiles by eating their eggs — to designate in 



popular language a 

 large number of Insects 

 whose main purpose in 

 life is to keep down the 

 numbers of other 

 Insects. They are 

 sometimes spoken of 

 as ichneumon-^/es, but 

 this is a somewhat 

 misleading name as the 

 term fly properly signi- 

 fies a two- winged In- 

 sect, whilst these have 

 four wings and belong 

 to that order 1 of In- 

 sects which includes 

 the bees and wasps. 

 I c h n e u m o n - w a s p s 

 would be a less objec- 

 tionable form. The 

 number of species coni- 

 prised in this group is 

 enormous — even in 

 Britain more than 

 twelve hundred have 

 been catalogued — and 

 yet the general public 

 knows almost nothing 

 of them. As indicated, their natural office is to keep down the numbers ol plant- 

 eating Insects. If it were not for the attacks of these ichneumons sonu' ol the cater- 

 pillar pests that afflict the fruit and vegetable grower would produce so enc^-mous a 

 percentage of moths that succeeding generations of the species would show such 

 progressive increase as would mak(> the industry impossible. No one knows better 

 than the breeders of butterflies and moths the ext(Mit of this parasitism, for tlieir 

 disappointments in rearing the perfect Insects from eolleeted caterpillars are botli 

 numerous and frecpient. Yet the fruit-farmer and the gardener know little more 



' Jtymenopteia. 



Caterpillar of the Hammock-Moth. 



Tlic moth gets its name from a habit of the caterpillar, which utilizes its own excrement for the 

 manufacture of a spindle-shaped case into which it can retire when alarmed. This is suspended 

 from a twig, and the caterpillar, taking hold of it with its hind-claspers, stretches out to almost 

 full length and feeds upon the leaves within reach all around. 



