3«4 



XEW YORK STATE Ml'SEUM 



Life history. The life liistoi')- of this species has been carefully studied 



by l)r llo])kins. ami the fdllowins^' is liis summar_\- : 



These obserx ations would also intlicate that activity ceases in the fall 

 by about the middle of t)ctober, when all stages of the insect may occur in 

 the bark of infested trees where they, with the probable exception of the 

 cgt^'s and pupae, remain until the first week in June Activity then com- 

 mences, the mature larvae c]iani;e to pupae, and by the middle of June 

 those that pass the winter in the adult stas^e emerj^e and commence to exca- 

 vate galleries and deposit e^'ij^s. The adults from llic hiljernatint,'- larx'at^ 

 of different sta^t-s, develop and continue to emerge possibly until the last 

 of August. Therefore the eggs deposited by the late developing beetles 

 produce larxae which do not complete their development until Iul\- or 

 .\ugust of the next year. Thus, the period of de\elopment may vary irom 

 about 70 davs to about 12 months, but all broods from eggs to matured and 

 emerging adults remain in the bark aljout 12 months, of which they are 

 dormant aliout se\(/n and a half ami acti\'e four ami a hall. 



Natural enemies. This sp<-cies is subject to attack l)y several natural 

 enemies. The commonest parasite, according to Dr Hopkins, is Brae on 

 simplex Cress., a well known species which lives at the expense of a 

 number of wood borers. TIh; antlike clerid beetle, I h a nasi m u s n u 1) i- 

 lus Kl., is said bv Hi' Hopkins to be a ver\- efficient enemy of this 

 species. He states that the atlult emerges from the bark of infested trees 

 somewhat earlier ihan the spruce destroying beetle antl remains hidden 

 thereon till the liark l)<)rers commence to emerge, when it pounces on and 

 devours them. It also follows the beetles to other trees and continues to 

 |)r(_'\' on them, and while it does not enter the galleries, it tle|)osits eggs at 

 th(;ir entrances, so that the active reddish larxae hatching therefrom can 

 readily enter and feed on the bark l)eetle larvae. The clerid larvae on 

 attaining full growth retire to the central Dendroctonus galleries, pupate 

 and transform to the adults. 



Woodpeckers are valuable checks on this sijecies. Professor Peck 

 states that many of the dead trees in two groves observeil In' him, had 

 their bark so chipped |}\ woodpeckm's, that the general hue of rhi- trunk 

 was a reddish brow 11 iiisiea<l of the usual greenish lirown. Dr Hopkins 

 slates that he is quite conlident that in man)' hundreds ot infested trees 

 examined, at least one half of the beetles and their young had bein 



