No. 4.] THE GYPSY MOTH. 303 



preventing the dissemination of the moth. The police were to 

 stop all vehicles going out of the infested territory, and examine 

 them ; to remove caterpillars found on them ; to stop all teaming 

 of infested material, and to enforce the regulations of the depart- 

 ment. The police outposts were examined by Professor Shaler, 

 who soon saw that the scheme was impracticable, and would not 

 attain the results for which it was intended. Less than two weeks' 

 trial of the system convinced the director of its inefficiency, and it 

 was discontinued by vote of the committee. 



Burlapping. 



During the spraying season experiments were made with various 

 traps for catching the caterpillars. By observing their habits, it 

 was seen that no trap would be effective unless it could be made 

 to serve as a hiding place. The cavities in trees to which they 

 resorted during the day were first burned out and then filled with 

 cement. This cementing was done in rainy weather, when spray- 

 ing was impracticable. A band of burlap was placed around the 

 trunk of each tree. The caterpillars crowded under these bands. 

 The men visited them daily and destroyed vast numbers, until all 

 that remained had pupated. In two days a gang of three men 

 killed in this manner 119,896 caterpillars and pupas. A week 

 after only 5,490 were found in the same locality, and a few days 

 later but 180. 



Contact Insecticides. 



Early in the season experiments had been made with insecticides 

 for killing the caterpillars and pupae by contact. Before pupating, 

 the caterpillars gathered in large numbers on the bark and in the 

 cavities of trees. In these situations they were killed by spray- 

 ing them with emulsions of whale-oil soap, soap powders and other 

 insecticides. Vast numbers were destroyed in this way. In one 

 instance two bushels of dead caterpillars and pupae were gathered 

 under a few apple trees. In one locality in Swampscott the stench 

 from their decaying bodies was sickening. 



In August and September the men were engaged in destroying 

 caterpillars, pupae, moths and eggs, wherever they were numerous. 

 As soon as all the eggs had been deposited, the force was again 

 reduced in numbers. The expert men who had been retained 

 were all set to work searching for and gathering eggs in the most 

 thickly infested portions of Maiden and Medford. There again 

 they were given the training which has been and will be of great 

 advantage in the inspection of other towns. In the mean time they 

 were able to destroy the greatest number of moths possible. This 



