90 THE STORY-BOOK OF SCIENCE 



the leaves. Jacques will tell you how much pains 

 he takes to protect his cabbage patch from the vora- 

 cious insect ; for, you see, caterpillars have a terrible 

 appetite. You will soon learn the reason. 



"Most insects behave like caterpillars. On com- 

 ing out of the egg, they have a provisional form that 

 they must replace later by another. They are, as it 

 were, born twice: first imperfect, dull, voracious, 

 ugly; then perfect, agile, abstemious, and often of 

 an admirable richness and elegance. Under its first 

 form, the insect is a worm called by the general name 

 of larva. 



"You remember the lion of the plant-lice, the 

 grub that eats the lice of the rosebush and, for weeks, 

 without being able to satisfy itself, continues night 

 and day its ferocious feasting. Well, this grub is a 

 larva, that will change itself into a little lace-winged 

 fly, the hemerobius, whose wings are of gauze and 

 eyes of gold. Before becoming the pretty red lady- 

 bird with black spots, this pretty insect, which, in 

 spite of its innocent air, crunches the plant-lice, is 

 a very ugly worm, a slate-colored larva, covered with 

 little points, and itself very fond of plant-lice. The 

 June bug, the silly June bug, which, if its leg is held 

 by a thread, awkwardly puffs out its wings, makes all 

 preparations, and starts out to the tune of 'Fly, fly, 

 fly!' is at first a white worm, a plump larva, fat as 

 bacon, which lives underground, attacks the roots of 

 plants, and destroys our crops. The big stag-beetle, 

 whose head is armed with menacing mandibles 

 shaped like the stag's horns, is at first a large worm 

 that lives in old tree-trunks. It is the same with 



