70 



THE VICTORIAN NATURALIST. 



sufficiently large to permit of its escape. This is managed by the 

 insect revolving round and round, at the same time by movements 

 of the wings thrusting the sickle-like projections through the 

 cocoon, cutting and breaking the strands of which it is composed. 

 The rapidity and power with which this is done is almost 

 incredible, and the noise made more resembles the gnawing of a 

 rat than anything else. When, by repeated thrusts, the moth has 

 made a weak line round the cocoon, it commences to butt against 

 the top in order to push the piece right out. At first this only 

 yields a little, being still held by many strands, but, as the insect 

 still keeps up its cutting exertions, the strands are gradually 

 severed, and the top is either thrust right off, or being held on 

 one side only turns back like a lid, the insect at once drawing 

 itself through the opening, and suspending itself for further 

 development. The time taken is never less than two hours of 

 incessant labour, and frequently much longer. When the moth 

 first emerges the little sickles are very conspicuous, but after it 

 has completed its development they are completely hidden by the 

 downy covering of the thorax and base of wings. 



Interior of cocoon of A. eucalypti Interior of cocoon after 



before emergence. emergence. 



Such is the method by which the Anthercea eucalypti breaks 

 through its cocoon, a method probably universal to the species of 

 the group, including the silk producers, Attacus yama-mai, A. 

 pemyi, A. mylitta, &c. 



A species of Hymenoptera parasitic on the Anthercea eucalypti 

 is likewise a cocoon breaker. Although as many as 18 or 20 are 

 sometimes feeding inside a single caterpillar, it generally manages 

 to construct its cocoon before its insidious enemies finally destroy 

 it, and consequently, when the parasites have devoured their host, 

 they find themselves enclosed within the compact walls which 

 resulted from its last exertions. 



Now in many cases, where a number of parasites exist in one 

 host, we find the first one emerging makes an exit for itself 

 through which all its companions subsequently follow. In the 



