378 ENTOMOLOGY 



Hibernation. Food is of minor importance as an incentive to hiber- 

 nation. Codling moth caterpillars, woolly bears (Isia Isabella) and 

 many other insects enter hibernation before there is any failure of the 

 food supply. 



Insects which feed on evergreen trees are not as rhythmical in 

 their hibernation as those which feed on deciduous trees. (Pictet, 

 Baumberger.) 



Some larvae are full-fed upon entering hibernation (codling moth) ; 

 while others are not (brown-tail moth) . Emergence from hibernation 

 depends immediately upon temperature, but it is possible that hunger 

 also is a stimulus to the renewal of activity. 



As metabolism is at its minimum in hibernating insects, their food 

 requirement is similarly small. 



Coloration. Food, as regards kind and condition, often affects 

 coloration, particularly pigmental coloration (see page 176). 



In the cotton boll weevil the color becomes darker with age; conse- 

 quently, hibernated individuals are the darkest found; but food also 

 influences the color. The smaller the size of the weevil, the darker 

 brown is its color; the largest weevils are light yellowish brown. The 

 principal reason for the variation, in the opinion of Dr. W. E. Hinds, 

 lies in the degree of development of the minute, hair-like scales, which 

 are much more prominently developed in the large than in the small 

 specimens, although the color of old specimens is often changed by the 

 abrasion of the scales. These scales are yellow in color, while the ground 

 color of the integument bearing them is a dark brown or reddish brown. 

 The development of the scales appears to take place mostly after the 

 adult weevils have become quite dark in color, but before the chitin 

 becomes fully hardened. They seem, therefore, to be, to a certain 

 extent, an aftergrowth which depends upon the surplus food supply 

 remaining .after the development of the essential parts of the weevil 

 structure. (Hunter and Pierce.) 



Food Relations in General. A phytophagous species which is 

 limited to one species of food plant frequently dies out in a locality 

 from having consumed or fatally weakened all its food plants (the but- 

 terfly L. philenor, on Aristolochia, in the North). 



Evidently, a species which has many kinds of food plants has ai 

 advantage (gipsy moth, grasshoppers, army worm, etc.). 



The quantity of food present becomes important for an insect that 

 is restricted to a single species of plant. It may be a plant that is 



