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from the trees and are carried long distances on vehicles, cars, etc. 

 There are several lines of cars riinnin<j;- through the infested district. 

 We found it necessar3'to clean all the trees along the lines of cars and 

 wiieie the cars stopped in the infested region, and many a place did we 

 have to clean out which cost time and money, and sometimes we had 

 to exercise the authority which was given us by the State to prevent 

 material being carried away by the railroad companies, lest it should be 

 infested with the eggs or caterpillars. 



These caterpillars before the first molt are different from what they 

 are after this molt. They have two sets of spines, those on the upper 

 part of the body being smooth and pointed, with a l)alloon-shaped swell- 

 ing at the basal third filled with air or gas. which probably has quite a 

 lifting power. The nun moth of Europe has the same structure in its 

 early stages, and some claim that the cateri^illars are swung off in the 

 air and fioat away by means of the lifting power of these miniature 

 balloons on the spines. We have never demonstrated that it gives any 

 aid in the distribution of the gyps}^ moth larv?e, but I am not i^repared 

 to say that it does not have a lifting iiower. 



The distribution is mainly in the caterpillar stage, when they get 

 upon moving objects. We find that the people who drive about in the 

 infested region carry it around the most, as doctors and milkmen, who 

 are going from house to house. They distribute this insect uncon- 

 sci(nisly and unintentionally. We almost invariably find their x:)remises 

 infested. 



We tried experiments to determine the distance a newly hatched 

 larva would crawl before it died of starvation. The thought I had in 

 mind was that if we knew the outer limit of the territory infested by a 

 colony we would then know how wide a belt it would be necessary to 

 burn to protect the territory outside. We put newly hatched cater- 

 pillars on a level table, on white paper or ordinary newspaper, thinking 

 that that would give them quite as good a chance to travel as they 

 could have in nature, and had persons follow behind them with a lead 

 pencil, with instructions to let them take their own course and not to 

 punch them along. Although the caterpillars took a peculiar course, 

 we got the number of feet thej' would travel before they died and the 

 number of hours it took them to travel the distance. One traveled 02 

 feet in 10 hours, one 143 feet in 12 hours, and another 144 feet before 

 it died. 1 luul the impression that if food were placed in the imme- 

 diate vicinity the caterpillars might i)erhaps direct their line of travel 

 in the direction of the food, but they did not. They did, however, 

 travel invariably toward the light — toward a window or lamp. I am 

 not surprised at that, because where these caterpillars are hatched, in 

 the cavities of trees, they naturally travel toward the light, and are 

 governed by tlie light more than by the odors or proximity of food. 



We also tried to ascertain how nuu'h a caterpillar would eat. These 

 experiments were i)erformed in the winter and in confinement. One 

 (1042— No. 2 5 



