THE GENUS DENDROCTONUS. 



117 



GENERATION. 



The eggs deposited by 

 the overwintered broods 

 of adults begin to hatch 

 during the latter part of 

 June (fig. 72) and the first 

 part of July , and continue 

 to hatch during July and 

 August. The larval de- 

 velopment is confined 

 principally to July and 

 August, but may con- 

 tinue to October. The 

 more advanced larvae 

 begin to transform to 

 pupae and adults during 

 the last week in August 

 and first week in Sep- 

 tember, and continue to 

 do so until hibernation 

 begins in the fall. No 

 evidence has been found 

 that any of the broods 

 emerge from the trees in 

 the fall; therefore there 

 is but one generation 

 annually. By far the 

 greater number of the 

 broods pass the winter 

 as young to matured 

 adults, and the hiber- 

 nation begins about the 

 middle of October. 



HABITS. 



This species prefers to 

 attack the older mature 

 living timber. It also 

 attacks standing tim- 

 ber weakened or injured 

 from other causes, and 

 trees felled by storm 

 and otherwise, though 

 usually not in such 







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