38 Agricultural Experiment Station, Ithaca, N. Y. 



natural increase in size. The full grown larva is described on page 32. 

 Soon after reaching maturity the larva begins to make preparation for 

 its transformation to the quiescent stage of the insect — the pupa. 



Pupation. — Within a tube, formed by rolling up one side of a leaf 

 or by bringing together two or three half devoured leaves, and 

 securely fastening everything with silken threads, the larva retreats 

 and lines the interior with a thin closely woven layer of silk. This 

 forms the cocoon of the larva, within which it is soon to undergo its 

 wonderful change to a pupa. In some cases the cocoon is formed on a 

 leaf or twig and covered on the outside with the fine wool taken from 

 the leaves or petioles, thus giving it a close i-esemblance to its surroand- 

 ings so that it is not easy to detect it. Those larvie which emerge first 

 on the earlier varieties of trees attain maturity and begin spinning 

 their cocoons in the latter part of May. The date of pupation varies 

 from June 1st to the 25th in this State. The pupa is described on 

 page 33. 



The pupa ( Fig. 2, a and h) lies quietly in its silken chamber for about 

 ten days. It then pushes its head through one end of the cocoon, and by 

 the aid of the rows of the tooth-like processes on its dorsum it works 

 itself along until the greater portion of its body projects from the end 

 of the cocoon. The pupal skin then splits open over the head and 

 along the back and sides, and the delicate little moth emerges. 



Habits of the moth. — After crawling forth from the pupal skin and 

 waiting a few minutes for its wings to expand and dry, the moth flies 

 away and is soon ready to begin its mission of the perpetuation of the 

 species. The moths begin to appear as early as June 5 in this State, 

 and all have not emerged by July 10. They are the most active at 

 night. During the day they remain quiet on the trunk and limbs of 

 the tree with the wings folded roof -like over the body. In this posi- 

 tion they so closely mimic the bark of the tree as not to be readily 

 seen. The moths lived about two weeks in our cagfes. 



Oviposition. — Three or four days after emerging, the moths copu- 

 late and egg-laying begins. Oviposition takes place mostly at night. 



FiQ. 6. — Egg showing embryonic larva within, greatly enlarged. 



The eggs are usually laid singly on the under side of the leaves; some 

 were found upon the upper surface and sometimes from two to seven 



