THE PINE INVESTIGATION. 369 



bably New Jersey 1 in which more or less pine or spruce died 

 during 1391-2 evidently from the invasion of Dendroctonus 

 frontalis is something over 50,000 square miles. And doubt- 

 less the total area in which a greater or less number of conifer- 

 ous trees were killed by the insect, if the facts could be learned 

 would make the total invaded area north of the southern 

 borders of Virginia and West Virginia, at least 75,000 square 

 miles. 



In West Virginia alone, the infested area included about 

 15,000 square miles, and it is very evident that whatever coni- 

 fers grew in any quantity in Virginia, Maryland and southern 

 Pensylvania, the insect made its presence known by conspic- 

 uous groups of dying trees. 



TWO REMARKABLE FEATURES OF THE INVASION. 



Although Dendroctonus frontalis has been recorded from 

 New Brunswick to Georgia, and from the Atlantic to the Paci. 

 fie coasts, it had been, previous to 1890,considered a rare species 

 and was represented in but few collections in this country 

 and Europe. That it should make its appearance within a few 

 yearri in sufficient numbers to take the character of an invas- 

 ion, attack and kill pine and spruce timber upon thousands of 

 square miles, and threatening the total destruction of the coni- 

 ferous forest and shade trees of the eastern United States, was 

 a most remarkable occurrence. 



This sudden appearance of the species in such destructive 

 numbers, followed by its sudden and universal death over the 

 vast area, mentioned, were in fact two remarkable occurrences 

 the equal of which has probably never been recorded. 



Devastating invasions by locusts, chinch bugs, army worms, 

 and forest insects, have been recorded from time to time, but 

 in most cases if not all, I believe, so far as noted, the invading 



1. I have not conducted investigations in Virginia. Maryland, Pennsylvania, or New 

 Jersey , but from car window observations and information with reference to the dying 

 of pine trees in these states in the same way, and during the same period, as in West 

 Virginia, I am confident that it was from this same cause. 



