FOOD PLANTS OF THE GIPSY MOTH IN AMEEICA. 3 



caterpillars were fed upon the foliage of two trees of the same species, 

 and care was taken that the foliage for each lot was always secured 

 from the same tree. The experiments were begun by using 100 cater- 

 pillars that had just hatched for each lot, the plan being to carry on 

 the feeding tests during each of the 6 caterpillar stages (PI. I, fig. 1) 

 in order to determine any variation in feeding habits in the different 

 larval stages. In conducting these experiments special feeding trays 

 were constructed, and the many details in the keeping of notes and 

 records, the collection of foliage, etc., were worked out. To supple- 

 ment these experiments and to give data which would furnish a 

 check on the results secured, observations were made throughout the 

 infested region during the summer of 1912 on the feeding habits of 

 gipsy-moth larvae in the field. 



In 1912 the infested territory was divided into 5 sections for the 

 purpose of determining the natural increase of the gipsy moth under 

 varying field conditions. This work has been supervised by Mr. 

 C. W. Minott, and the sections have been in charge of Messrs. H. E. 

 Gooch, I. L. Bailey, E. A. Proctor, J. V. Schaffner, jr., and W. A. 

 Shinkwin. As a part of the summer work each of these men, with 

 one assistant, has secured notes and information on the feeding habits 

 of the gipsy-moth larvae. The food-plant work has now been carried 

 on both in the field and at the laboratory at Melrose Highlands, Mass., 

 for three consecutive years — 1912, 1913, and 1914. 



During the summer of 1912 and 1913 a small sublaboratory was 

 maintained at Worcester, Mass., through the courtesy of the board of 

 park commissioners of the city of Worcester. The experiments were 

 in charge of Mr. C. W. Collins in 1912 and of Mr. E. Wooldridge in 

 1913. 



The object of the work at this laboratory was to determine whether 

 the same results would be secured from foliage gathered in an area 

 where the gipsy moth had never become abundant and defoliation had 

 not existed, as compared with foliage taken from the somewhat de- 

 bilitated tree growth in eastern Massachusetts, where many of the 

 trees had been defoliated one or more times. The results secured in- 

 dicated that no marked difference could be noted from foliage secured 

 from these two regions, hence the sublaboratory was discontinued at 

 the end of the second season. 



The experimental work on food plants of the gipsy moth has now 

 reached a stage from which reasonably conclusive results may be 

 secured. The information is of special value since it forms a work- 

 ing basis for reforestation in the infested areas and is of value in sug- 

 gesting the tree species which will be more immune from gipsy-moth 

 attack. 



