374 WEST VIRGINIA EXPERIMENT STATION. 



widely varying climatic conditions. If, however, the devasta- 

 tion was caused by a southern variety of race, and from its mi- 

 gratory habits extends northward only as opportunity offers, 

 it would doubtless be killed by excessive low temperature; but 

 if it were a species which has long been established in the 

 northern sections of the United States and Canada, I doubt the 

 possibility of its being killed by the cold. 



Therefore, while I was led to believe, in May, 1893, when so 

 many examples of this species were found to be dead, that their 

 death had been caused by the severe cold of the previous win- 

 ter, I was subsequently led to believe that unfavorable climatic 

 conditions was not sufficient in itself, to cause the extermina- 

 tion of the species. Therefore, evidences of other causes were 

 looked for and considered. 



INSECT DISEASES. 



If the insect was not killed by freezing or other unfavorable 

 climatic conditions, it was evidently killed by a disease or dis- 

 eases. During my investigations in Hampshire county, in May, 

 1892, I discovered that many of the adults of the beetle were 

 covered with a white mealy substance, which indicated that a 

 fungus disease was attacking the insect. This same condition 

 was frequently met with during subsequent investigations. 

 Specimens of the beetles so affected were sent, through Dr. C. 

 F. Millpaugh,to Prof. Peck, of Albany, N. Y.,for identification; 

 who found that it was a new fungus of the family Tuberculan- 

 iaceae^ and named it Cylindrocola dendroctoni. 1 This disease 

 was found to occur quite frequently in different sections of the 

 State during subsequent investigations in 1892; but never com- 

 mon enough in the form in which it was first recognized, to in- 

 dicate that it would produce an epidemic. The easily recog- 

 nized character of the disease is a creamy white mealy sub- 

 stance, covering the bodies of dead beetles, and lining the walls 

 of the galleries in front and behind the dead insect. 



Later in the summer and fall of the same year I observed 

 that both the adults and larvae were dead in some of the in- 



1. Described in Flora of W. Va., Bull. No. 24, W. Va. Agric. Exp. Station, p. 516. 



