Page:Insects - Their Ways and Means of Living.djvu/339

 CATERPILI.AR 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. 15o). The first performance of this sort was observed on May 15 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 I2 and 13. During the next few davs other caterpillrs 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 afternc;on. 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 davs following the time when the first caterpillar departs. ne of the two tents from which the general exodus was noted on May 19 was opened on the 2lSt and was fimnd 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 from the eggs on April 8, 9, and Io, 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 çth came flore a colony that began to hatch on April 1% gving an observed minimum of thirty-six days. After the mature caterpillars leave the tents, they wander at large and feed wherever they find suitable

INSECTS