250 



COLLEGE ZOOLOGY 



Walking stick 

 (Orthoptera) 



Labium in place 



Dung beetle (Scarab) 

 pushing a ball of dung 



(Coleoptera) 



Labium of 



dragonfly naiad 



(Odonata) capturing 



food 



Water strider 

 (Hemiptera) 



Oak apple gall 

 of gall wasp 

 (Hymenoptera) 



Caddisfly larva 

 (Trichoptera) 

 with abdomen in 

 pebble covered case 



Paper nest of 



hornet (Hymenoptera) 



A musician, the 

 snowy tree cricket 

 (Orthoptera) 



Figure 149. Special structural and physiologic adaptations of insects. 



that is, they are sexually dimorphic. This 

 often occurs, for example, in butterflies of 

 the genus Papilio. Often insects are pro- 

 tected from their enemies by their colora- 

 tion. Examples of what are known as pro- 

 tective coloration, protective mimicry, etc., 

 are common among insects. 



SOCIAL INSECTS 



Various types of association occur among 

 animals. Many protozoans live in colonies. 

 The same is true of coelenterates, where the 

 members of a colony may differ conspicu- 

 ously from one another. In many cases ani- 



