58 



THE SCOLYTID BEETLES. 



the middle of June and that all are out by the last of July. Broods 

 from eggs deposited by overwintered parent adults probably develop 

 and emerge by the first or middle of June. 



FIRST GENERATION. 



The overwintered young adults deposit their first eggs early in 

 May, and the excavating of galleries and oviposition continue prob- 

 ably into June, especially if the parent adults leave the completed 

 galleries to excavate others, which they evidently do, though the 

 general and principal attack by the overwintered broods is from the 



Fig. 19. — The southern pine beetle. Egg galleries and larval mines; a, Entrance; &, entrance burrow; 

 *^. egg gallery; d, normal larval mine; e, abnormal larval mine; /, terminal; g, ventilating bur- 

 rows. Slightly reduced. (Author's illustration.) 



middle to the last of May. The larvae begin to hatch early in May 

 and continue their active development during June, the more retarded 

 individuals continuing active into August. They begin to trans- 

 form to pupsB and adults about the middle of June, and continue until 

 the retarded individuals are all transformed, in August or later. 

 The developed broods begin to emerge toward the last of June and 

 continue to come out during July or until all of the retarded broods 

 and individuals are out in August and September or later; but 

 practically all of the normally developed broods of the first generation 

 are out by the last of July. 



