29G Agricultural Experiment Station, Ithaca, N. Y. 



caterpillar keeps the interior of its home neat and clean by using 

 the small hole in the upper end of the case as a back door out of 

 which all of the excrement is ejected. 



Some of the caterpillars become full grown by June 4th, but 

 most of them continue feeding until about June 20th. Thej then 

 seek a suitable place, usually on the leaves but sometimes on the 

 branches, where they securely fasten their case with silk, in nearly 

 the same position in which the caterpillar holds it while feeding. 

 So securely are they fastened that they remain in place long after 

 they are of any further use to the insect ; this fact accounts for the 

 cigar-shaped cases sometimes found among the small curved hiber- 

 nating cases on the branches in winter, as shown on the right hand 

 branches in Fig. 59. 



Pupation. — If one of these cigar-shaped cases be cut open about 

 ten days after it was fastened as described above, there will be 

 found inside, not the dark orange- colored caterpiller, but a light 

 brown quiescent object, known as the pupa. Thus these cigar- 

 shaped cases serve both as a summer suit for the caterpillar and as 

 a secure cocoon within which the insect undergoes its trauformations 

 to the adult stage. 



After fastening its case, and before changing to a pupa, the cater- 

 pillar in some manner turns around in its case, for the head end of 

 the pupa is always found nearest the upper end of the case. 



Emergence of the Moth, and Egg- Laying. — About ten days after 

 the change to a pupa takes place in cigar-shaped cases, there 

 emerges through the lipped orifice in the upper end of the case a 

 minute steel-grey moth— the adult insect (Fig. 56.) In our cages, 

 some of the moth emerged as early as June 25th, but others did not 

 appear until July 15th. 



The moths remain at rest on the leaves during the day. They 

 doubtless feed but little, if any, and do no damage. Some of the 

 moths that emerged June 25th had laid eggs three days later. In 

 our cages, most of the eggs were snugly tucked away among the 

 numerous hairs on the undersides of the youngest leaves near the 

 mid ribs ; some were similarly laid on the young, hairy branches. 

 They are apparently not glued to the hairs, as they are easily 

 dislodged. 



The eggs are of a delicate light lemon-yellow color, and quite 

 deeply pitted over their entire surface with triangular depressions 



