More Beetles 



and often with its poisons, each plant tried 

 would be a perilous innovation, to which the 

 insect, repelled by the first mouthfuls, would 

 never consent. How greatly preferable to 

 these dangerous novelties is the invariable 

 dish consecrated by ancient' custom ! This, 

 no doubt, is why the vegetarian insect is 

 faithful to its plant. 



How is this division of the earth's abun- 

 dance among its consumers effected? We 

 can hardly hope to understand the problem; 

 it Is too far beyond our methods of research. 

 The most that we can do is, by experimental 

 methods, to explore this corner of the un- 

 known a little, to seek to discover how far 

 the insect's diet is fixed and to note its varia- 

 tions, if any. This will give us data which 

 the future will employ to carry the problem 

 farther. 



Towards the end of the autumn, I had 

 placed in the vivarium two couples of the 

 Stercoraceous Geotrupes, with an ample heap 

 of provender obtained from the Mules. I 

 had no plans as regards my captives; I had 

 put them there because It was an old habit of 

 mine never to lose an opportunity. Chance 

 had set them within my reach; chance would 

 do the rest. 



218 



