CHAPTER IV 



THE BEETLE : A STUDY IN ECOLOGY 



Among all animals the beetles (Coleoptera '-) are character- 

 ized by having developed in the rlirection of passive resist- 

 ance to their enemies through the acquisition of a hardened 

 exterior. We know that seeds are preserved from the depre- 

 dations of many prej'ing animals and are protected from 

 unfavorable climatic conditions by an outer covering which 

 has a great variety of forms, but is always hard, angular, and 

 unattractive. So, likewise, the beetles are distinguished, on 

 the whole, by hardness, angularity, and unattractivencss as 

 compared with the butterflies. Let us see how the insect t^qDe 

 which has produced a body so gorgeous and frail as a butterfly 

 can be so modified as to form a beetle. We notice first that 

 the pair of front ^nngs (called elytra) are gi-eatly thickened and 

 hardened so that they can no longer be used for flying but serve 

 only to protect the membranous hind mngs which are folded 

 beneath them and on which flight depends. The cuticula of the 

 head has become greatly thickened, feeding is accomplished 

 by powerful biting jaws, the horny legs possess powerful spines 

 and end in claws. These profound modifications of the body 

 serve likemse to prevent the loss of the fluids of the body so 

 that beetles can withstand the dryness of deserts as well as 

 great extrem(>s of heat and cold. In fact, the hard and rigid form 

 of the beetle which makes it ]iossi).ile for it to live under very 

 extreme conditions jjermits it to occu]iy every niche in nature. 



'koleos. sheath; plcros, wing. 

 GO 



