278 THE LIFE OF AN INSECT. 



up in a membranous case, out of which there seems 

 no escape ; but there is a way, and the manner in 

 which the insect gets out of its prison is a remark- 

 ably curious one, well repaying the trouble of a 

 little close observation. At the larger end, under 

 which the head of the fly lies, and from which it 

 always issues, there is commonly a sort of lid which 

 can be pushed off like the lid of a box, and the insect 

 can then walk out at pleasure. But in the case of 

 the pupa of the blow-fly this lid is not very easily 

 removed, and the fly, therefore, is furnished with 

 a most ingenious method of thrusting it off. On 

 opening the larger end of such a pupa, if the fly 

 within is ready to come out, a most curious phe- 

 nomenon will be seen. The insect moves towards 

 the lid, and there begins to blow out its head in 

 the most extraordinary manner, swelling it to 

 twice its natural size ; a moment after it will 

 resume its natural size ; 

 then again it will puff it 

 out, making its two eyes 

 to start asunder, and its 

 head to assume several dif- 



m SUCCCS- 



sion! Two representations are annexed of the 



