THE ANIMAL FOOD OF BIRDS. 49 



not affect them so seriously as they do the insects of many 

 other groups. 



The leaf-miners differ from the leaf-rollers in that the larvae 

 live within the tissues of the leaf, as in the case of the apple 

 leaf-miner illustrated on the opposite page. 



The families of looping or measuring caterpillars Geome- 

 tridce and its allies are of special interest from an ornitho- 

 logical point of view because they contain many species which 

 in their larval state so closely resemble small twigs that they 

 easily escape the notice of birds. A few species, like the 

 canker-worm, are of much economic importance on account 

 of their injuries to the foliage of fruit and shade trees. Such 

 species, as a rule, are less perfectly protected in their resem- 

 blance to twigs than others, and Avhen abundant are freely 

 eaten by birds. The moths of these families have slender 

 bodies and comparatively large wings, although sometimes the 

 females are wingless. 



The great family of night-flying or ow^let moths called by 

 entomologists Noctuidce 

 includes a large number of 

 the most injurious insects. 

 The boll-worm of cotton, 

 the army-worm, and the 

 various cut-worms, all be- 

 long here. The cut-worms 

 are rather thick, naked 

 worms which hatch from 



THE ARMY-WORM. 



eggs laid by medium-sized (Frnm New York Experiment #/,>.) 



moths. Most of them feed 



upon grass or clover when young, becoming half grown before 

 \vinter. They hibernate beneath some shelter and in spring 

 <:ome forth in search of food, attacking a variety of young plants 

 by biting off the stems and feeding on the leaves. They become 

 full grown during spring or early summer, pupate beneath the 

 soil surface, and a fortnight or more later emerge as moths. 



4 



