The Palmer-Wokm. 101 



We saw the caterpillars only on apple trees in 1900, and had 

 complaints of their ravages from apple-growers onlj^ 



Thus the favorite food of the insect seems to be the folia<re of 

 apple and oak, and on the former tree the frnit is also included in 

 the caterpillar menn, while on the oak, cnriouslj enongh, the " oak- 

 apple '' galls are also eaten. 



The Story of the Palmer- Worm's Life. 



l^othing has been recorded of the life and habits of the palmer- 

 worm, except for tlie months of June and July. During these two 

 months the caterpillars do most of their feeding and soon transform 

 through the pupa stage into the little moths ; these three stages in 

 the life of the insect were described in detail bv Ilari-is and Fitch 

 in 1853, but there is no hint of how the insect spends the remaining 

 ten months of its yearly life-cycle. AVe have been able to follow 

 it from July nntil it goes into hibernation, and are thus enalJed to 

 give a reasonable guess as to how it lives during the rest of the year. 



Its appearance and work in June. — The records of both pre- 

 vious outbreaks — in 1791 and in 1853 — -of this insect state that the 

 caterpillars lirst attracted attention from the 10th to the 15th of 

 June. Our IS^ew York fruit-growers also iirst noticed the insect 

 about this time in June, 1900. The caterpillars or palmer- v/orms 

 were then mostly over half-grown, and their work was most 

 conspicuous. 



They skeletonized the leaves (see figure 28), usually leaving the 

 veinlets, but sometimes eating irregular holes through the leaf, and 

 often devouring nearly all of the youngest and tenderest leaves 

 at the tip of a branch, as shown on the branch near the center 

 of the upper part of figure 28. Their work on the leaves is 

 very much like that of canker-worms. Sometimes two or three 

 leaves are fastened together with silken threads spun by the palmer- 

 worms thus forming a sort of nest within which they feed. Often 

 they feed openly on the surfaces of the leaves, but many of them 

 draw over with silken threads one edge of the leaf at the side or 

 near the tip, as is well shown in lower corner of figure 25, thus 

 forming a partial tube or roll within which they feed underneath 

 their silken bridges, as shown in the same figure. 



