392 WEST VIRGINIA EXPERIMENT STATION. 



little pests, in order that proper measures may be promptly 

 adopted to prevent as far as possible the serious losses they are 

 capable of causing. 



DESTRUCTIVE BARK BEETLES. 

 Order OOLEOPTERA ; Family SCOLYTIDAE. 



The, Genus Dendroctonus. 



The genus Dendroctonus, which is represented in America, 

 north of Mexico by six well recognized species, 1 is of especial 

 economic interest, since it includes probably the most destruc- 

 tive enemies of the pine, spruce and larch, that is known The 

 genus is also of interest on account of the remarkable habits 



.fig. LVIII. Species of Dendroctonus: a, D. terebrans: 6, D. rufl 



pennis; c, simplex; d, D. similis; e, D. approximate; 



/, D. frontalis. 



and wide distribution of its representatives. Only four well 

 defined species have as yet been observed in West Virginia, but 

 the fact that some of the others may, from time to time, make 

 their appearance here and prove destructive to our coniferous 

 forest or shade trees, seems to warrant a brief reference to the 

 distinctive characters, distribution, and habits of each of the 

 common eastern species. The species vary so much in size, 

 color and markings, and are so nearly allied to each other, that 

 the larger ones are exceedingly difficult to correctly identify 

 Dendroctonus terebrans^ Oliver, Fig. LVIII, a. This is the 



1. Sinceythis was written a large series of specimens from all parts of the country 

 have been submitted to me for study from the National collection, and I have under 

 taken a complete revision of the genus, to place a number of new species and varieties 

 which will be the subject of a special paper which I hope to publish at some future 

 time. 



