INTRODUCTION 19 



The half -grown caterpillars may hibernate either as free 

 creatures under boards, stones, or in the turfy grass, or 

 they may be protected by special shelters which they have 

 provided for themselves in their earlier life. In the case 

 of the latter each may have a shelter of its own or there 

 mayfbe a common shelter for a colony of caterpillars. 

 Among the examples of those hibernating in miscellaneous 

 situations without special protection the caterpillars of 

 the Tawny Emperor, the Gray Emperor, the Pearl Cres- 

 cent, and some of the Graylings are examples. Among 

 those which hibernate in individual shelters the Sovereigns, 

 among which our common Viceroy is most familiar, 

 are good examples. Among those which hibernate in 

 a tent woven by the whole colony for the whole colony 

 the Baltimore or Phaeton butterfly is perhaps the best 

 example. 



The caterpillars that hibernate when full grown may be 

 grouped in a way somewhat similar to those which are half 

 grown. Many species simply find such shelter as they 

 may at or near the soil surface. The Clouded Sulphur is a 

 good example of these. Others pass the winter in in- 

 dividual shelters made from a leaf or blade. Several of 

 the larger Skippers are good examples of this condition. 

 So far as I know none of our species pass the winter in 

 colonial shelters when full grown. 



It would be natural to suppose that the great majority 

 of butterflies would be likely to hibernate in the chrysalis 

 state. Here is a quiet stage in which the insect is unable 

 to move about or to take any food, in which it seems en- 

 tirely dormant and as a rule is fairly well hidden from the 

 view of enemies. We find, however, that only a rather 

 small proportion of our butterflies has chosen this stage 



