68 



AUTUMN AND WINTER 



spends the winter as a chrysalis, emerging in May. Many 

 other caterpillars leave their food-plants as the sap goes out 

 of them and the nights grow cold, and hibernate in the earth, 

 or wrapped to some twig or bough. The most conspicuous 

 of this group of caterpillars is that of the fox moth, which is 



CATERPILLARS OF THE PALE TUSSOCK MOTH 



very plentiful in August and September on heathy commons 

 and dry hills, and readily attracts attention by its thick soft 

 chestnut hair. Though its thick mantle serves to warn birds 

 to keep aloof, it is no protection against ichneumon flies. 

 These are some of the most dangerous enemies of moth and 

 butterfly life. The flies pierce the skin of the young cater- 

 pillars with their slender ovipositors, and insert a number of 

 eggs. The larvae feed within the larger caterpillar's body, 

 and eventually kill it. Sometimes the victim turns duly into 

 a chrysalis, but a troop of winged parasites emerge instead of 

 the butterfly or moth. Other caterpillars waste away before 

 they can change ; and we sometimes see the shrunken body 

 of a fox caterpillar lying on the grass with the white oval 

 pupae of the ichneumon fly bursting from its skin. The 

 delicate callousness of this process is less objectionable when 

 the victim is one of our own garden pests. When the last 



