cuous feeders, and most species are restricted to certain species or genera of plants. 

 Even when they feed upon different plants, observation shows that, having begun 

 to feed upon a certain plant, they prefer this to all others, and do not willingly ac- 

 cept anything else. I have noticed frequently that larvse which may for instance 

 feed in nature upon the wild plum or the lilac, having begun to feed upon the one 

 will steadily refuse the other if offered to them. On several occasions I have lost 

 broods of caterpillars by attempting to change their diet, though knowing well that 

 the species is found feeding in nature upon the plants which I have offered to them. 

 Almost every plant has a butterfly or moth which is partial to it, and one of the 

 most wonderful things in nature is the way in which the female butterfly, without 

 having received a botanical education, is able to select the plant which will best 

 meet the needs of her progeny, which she never lives to see. 



The eggs are deposited sometimes singly, sometimes in small clusters, sometimes 

 in a mass. Fertile eggs, soon after they have been laid, undergo a change in color, 

 and it is then possible with a magnifying glass to see through the thin shell the form 

 of the caterpillar which is being developed within. 



When the development is completed the caterpillar emerges either from an 

 opening at the side or at the top of the egg. Many species have eggs provided with 

 a sort of lid, a portion of the shell being separated from the remainder by a thin 

 section, which finally breaks under the pressure of the enlarging embryo within, 



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