33 



manner in which these instructions were carried out, the time and 

 labor involved in the work", and the value of Mr. Gary's observations 

 will be indicated by his report. 



Mr. Cary commenced these experiments May 29; his report was 

 submitted October 6 and 10, 1900. It is as follows: 



Camp in the Meadows, Maine, 



October 6, 1900. 

 Dear Professor Hopkins: I send you herewith report of my observations this 

 season. They do not go very far toward solving the problems suggested, but as 

 to Dendroctonus it seems to me they do teach considerable. 



Sincerely, yours, Austin Cary. 



All of the trees girdled are of Red Spruce, and unless otherwise mentioned were 

 to all appearances healthy. 



The inferences to be drawn from the results depend considerably on surround- 

 ings, the lay of the land, and the relation of the girdled trees to infested and 

 healthy ones. I will therefore g oup my notes according to localities. 



GrROUP I. 



Group I is at edge of Wighfs cutting of winter of 1899-1900 and near the clump 

 of infested trees examined on May 28 by yourself and the writer. Unless other- 

 wise stated, the trees were hack- girdled by striding an ax through the bark and 

 into the sapwood around the trunk 3 to 5 feet above the base. 



Trees girdled on May 29. 



Tree No. 2: Diameter 28 inches: examined June 19, July 9, September 1, and 

 October!; not attacked by Dendroctonus.' A few Xyloterus' 2 entered the wood 

 in the girdle. 



Tree No. 3: Diameter 12 inches; girdled by A. D. H.; examined on June 19, 

 July 9, and September 1; not attacked by Dendroctonus. October 4. seemed to be 

 losing leaves; sapwood at girdle and for a foot above stained bluish one-half inch 

 deep. 



Trees girdled June 19. 



Tree No. 24: Diameter 13 inches. July 10, attacked by a few Xyloterus. Octo- 

 ber 4, no change. 



Tree No. 25: Diameter 18 inches. July 10, numerous Xyloterus entering at and 

 near girdle. October 4 , no change. 



These four trees are about 30 yards from infested trees and about 75 yards from 

 the clump of trees first examined on May 28. 



Tree No. 26: Diameter 20 inches; 30 yards from clump of infested trees, July 

 9, a few Xyloterus entering wood at girdle; bark infested with Dendroctonus, 

 Polygraphus :: especially abundant below the girdle; a few Sierus annectens found 

 below girdle. September 1, Dendroctonus larvae were observed. October 4, 

 recently developed beetles and a few Tetropium larvae occurred in the bark, with 

 numerous Xyloterus in the wood; the bark was then loose, the leaves down, and 

 the wood turning brown. 



Tree No. 27: Diameter, 15 inches; 40 feet from infested trees. July 9, infested 

 by Dendroctonus and Xyloterus in girdle; Dendroctonus galleries up to 3 inches 

 long, with numerous eggs. September 1, numerous larva? and pupa? of Denuroc- 



1 Dendroctonus piceaperda Hopk. '■' Polygraphus rufipennis, Kirby-Hopkins, 

 i Xyloterus bivittatus Kirby. 



3506— No. 28—01 3 



