THE ANIMAL FOOD OF BIRDS. 



51 



The highest group of the LepidopLera includes the familiar 

 butterflies. In their earlier stages they are caterpillars, many 

 of which form a portion of the diet of birds. 



Many of the larger butterfly larvae seem to be protected 

 from the attacks of birds by a disagreeable taste or smell. 

 The caterpillars of the beautiful papilios have a peculiar pair 

 of yellow or orange-colored Y-shaped organs concealed just 

 back of the head. When the larva is irritated these are thrust 

 out ; they emit a very disagreeable odor and are supposed 



A THANE-FLY. 



to be useful as a means of protection from birds and other 

 animals. 



The order of two-winged flies — Diptera — contains com- 

 paratively few families of injurious insects. The species most 



