520 COLLEGE OF AGRICULTURE 



terized by countless myriads of larvae in all stages of growth, 

 as well as in all stages of starvation. The trees were not en- 

 tirely denuded of foliage, but covered with larVEe which were 

 rapidly completing the work. Everywhere was to be seen one 

 vast crawling mass of green caterpillars, and the noise made 

 by the falling excrement and bits of leaves sounded like an April, 

 shower. In the mountain streams bushels of caterpillars were col- 

 lected in the eddies, their decaying bodies causing a decided stench. 

 It was this crawling mass of caterpillars that gave foundation for 

 the general impression that the larvae migrated in mass from 

 a stripped section of the forest to one where food was plentiful, 

 something on the order of the army worm. A careful study was 

 made of the problem with the result that no migration whatever 

 could be detected, except what would accidentally occur from 

 the worms crawling about. All of the larvje observed were, 

 technically speaking, negatively geotactic, that is, they had a ten- 

 dency to crawl up any perpendicular object they came to 

 whether it were a tree, rock, stump or weed. The fact that the 

 larvae were on the ground at all is explained by the countless 

 numbers feeding on a tree at one time. In feeding, the larva 

 eats out crescent-shaped areas from the leaf, frequently cutting 

 off a considerable portion of it which falls to the ground, in 

 many cases carrying the larva with it. In other instances as 

 the foliage is stripped from the tree, the larvae crawl to the out- 

 most twigs in search of fresh leaves, and may be either blown 

 off, or drop to the ground. These, starting out In any direction, 

 are as likely to crawl up a pine tree as any other. Those lar- 

 va not successful In finding food crawl about until, weakened 

 by starvation, they fall to the ground again, only to repeat the 

 search. In this way the infested region would be pushed far- 

 ther and farther away from the original colony, but during the 

 entire season could not be extended ovt: much new territory. 

 Even after the larv» are ready to pupa'.e it seems Boubtful If 

 they crawl down the trunks of the trees, but more likely simply 

 drop to the ground. Beyond much question this second zone 

 was made up of larvae which had been fortunate enough to 

 migrate in the right direction from the original infested area. 

 On one side of this area was a pasture, which was searched for 

 several hours, but no caterpillar could be found any distance 

 from the trees. This fact, also, led me to further doubt there 

 being a migration. 



Extending for a mile, or more, on all sides of this badly in- 

 fested zone was an area in which the larvae were quite numer- 



