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THE AMERICAN NATURALIST [Vol. LIV 



is due to a cannibalistic instinct of the caterpillar which 

 results in the disappearance of the excess individuals, 

 notwithstanding the fact that there is food enough for a 

 considerable series in a single corn ear. A similar can- 

 nibalistic habit has been reported in Hadena and Agrotis, 

 two other genera of the same family, and no less than 

 75 species of European Lepidopterous caterpillars are 

 known to be occasionally' predatory through temporary 

 aberrations of their trophic instincts. 



With such plasticity of behavior in several diverse 

 families and even with Lyccena arion and certain small 

 moths exhibiting a change in food habits during on- 

 togeny, it is not difficult to regard the origin of sar- 

 cophagy in Lepidoptera as due to independent changes 

 which have become firmly fixed in individual species or 

 genera. 



The habit of certain Tineid moths, including the 

 clothes-moth (Tinea) and some of its relatives, to feed 

 upon wool and other materials of animal origin is well 

 known, and other non-domesticated forms of the same 

 group exhibit similar food-habits. One African species 

 of Tinea lives at the base of the horns of a large water 

 antelope, where it forms tubes similar to those con- 

 structed by some other Microlepidoptera. The bee-moth, 

 Galleria mellonella, a commensal in the hives of the 

 honey-bee, subsists upon beeswax and bits of refuse said 

 to contain about 20 per cent, of nitrogenous matter. 

 Practically all of the caterpillars that subsist on foods of 

 animal origin are more or less closely related, but not 

 sufficiently so for us to entertain for a moment the belief 

 that the habit has not originated independently in numer- 

 ous instances. Why it should be restricted to a few 

 groups in one part of the order, may, I think, be ex- 

 plained on the following basis. Among the Microlepi- 

 doptera only do we find forms able to subsist upon plant 

 materials containing a very small amount of water {e.g., 

 seeds, dry fruits, grain, flour, etc.) as distinguished from 

 the tissues of growing plants. Even in the wood of trees, 



