394 WEST VIRGINIA EXPERIMENT STATION 



ton, Randolph county, which is closely allied ii' not identical to 

 this species. 



Dendroctonus simplex* Lee This species was thought by 

 myself and Mr. Schwarz to beideniical with D. rufipennis^ but 

 I am now convinced that it is a distinct species. It is uni- 

 formly smaller than D. rufipennis. It varies from 55. 5 mm. 

 or .20 .22 inches in length and from light to very dark brown. 

 This species is also widely distributed, but is evidently re- 

 stricted in its range as a destructive species to the so-called 

 Canadian life zone. 



Examples identified as this species were observed in great 

 numbers in larch by W. H. Herrington, in Canada and by Hub- 

 bard and Schwartz in Michigan. It was thought by Herring- 

 ton that the death of a large amount of larch was due to the 

 primary attack of this insect. It is also recorded from Lake 

 Superior, Colorado and California. 1 observed it in great num- 

 bers in the bark of standing and felled larch trees near Cranes- 

 ville, Preston county, W. Va. Many large trees had died and 

 the prevalence of the beetle and its presence in the bark indi- 

 cated that they were largely to blame for the trouble. It was 

 also found in the bark of recently felled spruce trees and logs. 



Dendroctonus frontalis, Zimm. This species is easily recog- 

 nized from those previously described, by its small size, dark 

 color, and broad head and thorax. It is recorded from Lake 

 Superior, the Virginias, Georgia, and Florida in the East, and 

 from Colorado, Arizona, and Californin in the west. It infests 

 and is destructive to indigenous and introduced pines and 

 spruces. 



Following will be found a more detailed description of this 



species and D. terebrans, together with an account of what 1 



have observed with reference to their habits and life history. 



THE DESTRUCTIVE PINE BARK BEETLE. 



Dendroctonus frontalis, Zimm. 



DESCRIPTION. 



Adult: Length, 2.2-4.2mm. or .8-.17 inches ; color, light brown 

 to black ; antennae and legs, yellowish to light brown ; head, 

 with front corsely punctured and channeled in both sexes, but 



