6 THE BOOK OF BRITISH BUTTERFLIES. 



Life -history of a Butterfly. 



A butterfly's existence commences inside an egg 

 very much smaller than an ordinary pin's head. These 

 eggs, though so small, exhibit marvellously delicate 

 workmanship when seen under the microscope, the 

 patterns varying greatly with the different species of 

 butterfly. The eggs must usually be sought for on the 

 under-side of the leaves of the plant on which the 

 caterpillar must feed, for the butterfly never makes a 

 mistake as to the kind of food that its young will require. 

 The eggs are hatched by the sun in a few days, except 

 in the case of some half-dozen butterflies, whose eggs 

 lie dormant till the following spring. As the time for 

 hatching approaches, they gradually become darker, and 

 a tiny creature, called a larva* or caterpillar, crawls out 

 through a little hole it has gnawed in one side of the 

 shell. The caterpillar falls to eating at once, and 

 doubles its weight in no time, unless it belongs to a 

 species which hibernates in the larval stage, when it 

 feeds little and grows but slowly till the next spring. 

 It very soon finds its coat too small, and when this 

 happens the little larva leaves off feeding for a time and 

 becomes restless, till a split occurs down the middle of 

 its back, and there emerges a new individual, usually 

 differing somewhat from the old one. This "moult," 

 as it is called, is repeated at least three times, but 

 oftener five or six. 



At last the insect reaches its full size, gives up feed- 

 ing for good and all, and prepares to retire from the world 

 for a week or two, possibly till the following spring. 

 Its skin is shed for the last time, and now a curious 

 creature appears, without legs, wings, eyes, and mouth, 



* Larva, mask. 



