THE PINE INVESTIGATION. 407 



come in contact with the timber and commence their operations 

 on the living trees. It also appeared from the conditions found 

 that no choice of trees or locality was made by the swarm, but 

 they attacked and killed those trees upon which they happen- 

 ed to settle in sufficient force to overcome the natural resistance 

 met with in the living bark. 



DISTRIBUTION. 



The fact that this insect has been recorded from the Lake 

 Superior region,and occurred from central Pennsylvania through 

 Maryland, Virginia, West Virginia, District of Columbia, and 

 North Caioliua in destructive numbers, and that it has been 

 collected in Georgia, Florida, Colorado, Arizona, and California 

 is good evidence that it may occur at any part in the United 

 States where the pines and spruces grow. 



In West Virginia it was found by me to be exceedingly com- 

 mon and destructive wherever the pine grew or was common, 

 at elevations varying from less than 500 to more than 4000 ft. 



Up to the time, July, 1891, when I found it so common in 

 Hampshire county, W. Va., it was conceded one of the rarest 

 species of the family and was represented in but a few of the 

 largest collections. Mr. Eichhoff, of Strasburg, Germany, had 

 but one specimen in his great collection of Scolytids of the 

 world,when I sent my first specimens to him for indentification, 

 and I have since found that there were but few examples in 

 any of the collections of this country. It was exceedingly com- 

 mon from Pennsylvania to Florida in 1891-2, but since the 

 spring of 1893 it has been exceedingly rare north of North Car- 

 olina. In fact, I do not know that a single living example has 

 been observed in this region since the fall of 1892.. Mr. 

 Schwarz, of the Division of Entomology, at Washington, informs 

 me that he observed it in Florida in 1894 (?) and I received it 

 from North Carolina in 1895, with a report that groups of pine 

 trees were dying. 



HOST PLANTS, 



I have observed this insect jn all af ppr native species of pine 



