APPLE-TREE CATERPILLAR — QUANTITY OF FOOD ATE. 189 



they wholly cease from feeding for one or two days, remaining 

 all the time within the nest, those portions of the brood which 

 are not ready to moult being at such times the only ones which 

 go out to feed. From the most exact observations which I have 

 been able to make, each worm appears to consume about two- 

 thirds of an apple leaf at each meal — the leaves being small 

 when the worms are young, and fully grown as they attain their 

 full size. A worm an inch long which I confined in a tumbler 

 fifteen days, noting the number and size of the leaves I fed to it, 

 ate on an average an ordinary sized apple leaf, two and a half 

 inches long and half as broad, daily. But thus confined, it took 

 no exercise, and spun no web ; and it thus required but half the 

 food, probably, which it would have consumed had it been at 

 liberty. I regard this therefore as confirming the correctness of 

 the observations which I had previously made. It thus appears 

 that each worm devours two leaves daily. And as each nest 

 contains about three hundred worms, every owner of an orchard 

 will perceive that with every caterpillar's nest which he allows to 

 remain upon his trees, the trees lose six hundred leaves daily. 



They always travel upon the upper side of the branches and 

 limbs. And each worm, wherever it goes, spins a thread of 

 silk, which not only gives it a more secure foothold, but serves 

 also as a clue to guide it back to the nest again. Much of the 

 traveling of these worms appears to be solely for exercise. As 

 one after, another has satisfied himself with food, he comes back 

 to the nest and walks around upon its surface in every direction, 

 thus adding new threads to it. Other worms having also com- 

 pleted their meal, are coming home to their tent every moment. 

 Thus its surface begins to become crowded and is perfectly black 

 with the multitude of full fed individuals which are rambling 

 about upon it, and the throng is constantly becoming more dense 

 with new arrivals from the feeding ground. Hereupon some of 

 them start away, up one of the limbs leading from the nest, and 

 which is covered with cobweb threads from having been so 

 often traveled before. Others follow after these leaders, and 

 the limb through its whole length is soon thronged and black 

 with a procession of worms, going out to its extremity and back; 

 thus making room on the surface of the nest for other individ- 



