CABBAGE WHITE BUTTERFLIES 179 



body well behind the head. Reaumur goes on to 

 describe the girdled pupae. 



Each end of the girdle is glued to the supporting 

 object. At first sight the girdle looks like a single 

 thread, but on examination with a lens it is found to 

 be made up of many threads, which are neither glued 

 together nor interwoven. It is sufficiently loose to 

 allow the body to move a little way in any direction, 

 and, what is of special importance, is loose enough to 

 allow the cast skin to be slipped 

 off beneath it. 



The larva attaches itself by 

 its claspers to a hillock of silken 

 threads, and remains quite still 

 for many hours before be- 

 ginning to spin the girdle. The 

 subsequent operations differ a 

 little in different Butterflies. 

 Reaumur kept several kinds in 

 captivity, and was rewarded by 



discovering three modes of procedure, each adapted 

 to the wants of a particular species. 



In one of the Hair-streaks (Thecla) the larva is 

 stumpy and covered with stout hairs. Having pre- 

 viously attached itself by its tail, it contracts the fore- 

 part of its body as much as possible, fastens the be- 

 ginning of a new thread to the support, and passes it 

 over its head to the other side of its body, where it 

 fastens it again. The head is employed in a peculiar 

 way to carry the thread across. Some notion of the 

 process can be got by holding a thread between the 

 finger and thumb of the left hand, and grasping it 



N 2 



