PREFACE xi 



their tails from side to side. And there they 

 remain, sometimes for weeks and sometimes for 

 months, till the time comes for the perfect butter- 

 flies to make their appearance. 



Then, one day, the skins of the chrysalids split 

 open, and out creep the butterflies. But if you 

 were to see them now you would never guess 

 what they were, for their wings are so tiny, and 

 so crumpled up, that you can hardly see them. 

 They climb up to some firm foothold, however, and 

 then remain perfectly still; and by slow degrees 

 the creases straighten out, and the wings become 

 larger and larger, and stronger and stronger, till 

 at last they reach their full size and strength, and 

 the butterflies, perfect at last, are able to fly away. 



That is the "life-history" of a butterfly; and 

 moths are developed in just the same way, except 

 that very often their caterpillars spin silken cells, 

 which we call "cocoons," and turn to chrysalids 

 inside them. And the chrysalids of moths, re- 

 member, are often known as " pupae." 



Then there are one or two other things about 

 these insects that I should like to tell you. One 

 is that their wings are covered all over with very 

 tiny scales. 



Of course you know that if you catch a butterfly, 

 and let it go again, your fingers are covered with 

 a kind of mealy dust. And if you look at a little 

 of this dust through a microscope you will find 

 that it is made up of thousands and thousands 

 of the smallest possible scales, all most beauti- 



