THE CATERPILLAR AND THE MOTH 



some terrible dream or as if pursued by a demon, hurries 

 outward along a branch, goes to the end of a spur or the 

 tip of a leaf, and without slackening continues into space 

 till the end of the support tickles his stomach, when sud- 

 denly he gives a flip into the air, turns a somersault, and 

 lands on the ground (Fig. 150). 



The first performance of this sort was observed on 

 May 1 <; in the Connecticut colonies. On the afternoon 

 of the 19th, twenty or more caterpillars from two neigh- 

 boring colonies were seen leaving the trees in the same 

 fashion within half an hour. Most of the members of one 

 of these colonies had their last molt on May 12 and 13. 

 During the next few davs other caterpillars were ob- 

 served jumping from four trees containing colonies under 

 observation. All of these went off individually at various 

 times, but most of them early in the afternoon. Many 

 caterpillars simply drop off when they reach the end of 

 the branch, without the acrobatic touch, but only three 

 were seen to go down the trunk of a tree in commonplace 

 style. 



The population of the tents gradually decreases during 

 several days following the time when the first caterpillar 

 departs. One of the two tents from which the general 

 exodus was noted on May 19 was opened on the 21st and 

 was found to contain only one remaining caterpillar. On 

 the evening of the 22nd a solitary individual was out feed- 

 ing from the other tent. The two younger colonies main- 

 tained their numbers until the 22nd, after which they 

 diminished till, within a few days, their tents also were 

 deserted. The members of all these colonies hatched 

 frorn the eggs on April 8, 9, and 10, so seven weeks is the 

 greatest length of time that any of them spent on the trees 

 of their birth. The caterpillar that left the tent on the 

 15th came from a colony that began to hatch on April 10, 

 giving an observed minimum of thirty-six days. 



After the mature caterpillars leave the tents, they 

 wander at large and feed wherever they find suitable 



[281] 



