THE GENUS DENDEOCTONUS. 91 



SEASONAL HISTORY. 



OVERWINTERING STAOES. 



The winter is passed in the inner bark on trees attacked the 

 preceding summer and fall, as parent adults in the egg gaUeries all 

 stages of larvae in^the larval mines and transformation cells, and as 

 broods of young adults in transformation cells; but prikcipallv 

 as larvae. 



ACnviTT OF OVERWINTERED BROODS. 



As soon as warm weather begins in AprH and May the over- 

 wintered parent adults extend their incompleted egg galleries and 



Fig. 51. — The Black Hills beetle {Dendroctomu panderosie): a. Adult; 6, larva; c, pupa, a, Greatly 

 enlarged; 6, c, less enlaiged. (Author's illustrations.) 



excavate new ones in the remaining hving bark on the dying trees 

 and deposit eggs. The overwintered broods of young adults begin 

 to emei^e from the trees by the middle of July, but the main swarm 

 does not appear until the last of July and first of August. Some of 

 the retarded broods continue to come out until October, or later. 

 The broods of larvae begin to transform to pupae and adults about 

 the middle of May, and continue to do so during the period from 

 June until September, or later, and begin to emerge in August. 



