THE SPRUCE INVESTIGATION. 249 



occur in one season, commencing with the first eggs deposited, 

 in the spring, but my observations lead me to believe that 

 owing to the shortness of the season at the high elevations 

 occupied by the spruce in this State there is generally but one 

 brood. 



Other Trees infested by it. Besides the black spruce, it has 

 been recorded from the larch in Michigan 1 and I have found it 

 in the larch in West Virginia. I also found a single example 

 excavating an entrance gallery in the bark of scrub pine on the 

 mountain near Morgantown. Dr. Packard 2 mentions that this 

 species infested pitch pine, but he undoubtedly referred to a 

 species of Dendroctonus^ certainly not to this species, although 

 he published a good illustration of the beetle from a drawing by 

 Dr. Bland and Miss Sullivan. 



Distribution. The species is evidently widely distributed 

 over North America, and doubtless occurs where spruce is in- 

 digenous. It has been recorded from New Hampshire to 

 Alaska and Georgia. In West Virginia it appears to be con- 

 fined to the Canadian Life Zone and the spruce area, since I 

 have never met with it in the cultivated spruces in any of the 

 other life zones. 



Previous Knowledge of its Habits. It appears that very 

 little has been previously recorded with reference to the life 

 history and habits of this insect, except such reference as the 

 writer has made to it in the publications referred to on another 

 page. The insect referred to by Dr. Packard, in the 5th Report 

 of the U. S. Entomological Commission, under the name 

 "Xyloterus bivittatus" as the beetle most concerned in the 

 ravages of the spruce forests of New England, may possibly 

 have been this species, since his description of the habits and 

 galleries could not have been the work of Xyloterus bivittatus* 

 which is not a bark miner, as will be shown further on. 



The Abundance of the Insect and Its Economic Relations to 



1. Cook and Davis, Michigan bulletin . 

 ?. 5th Rep. U. S. Ent. Com., p. 721. 



