68 



THE SCOLYTID BEETLES. 



of November and completed not later than the 1st of April, and in 

 the southern section it should be begun in December and completed in 

 February. If at least 75 per cent of the infested trees, including all of 



Fig. 30.— Egg galleries and larval mines of the southern pine beetle, and larval mines 

 of roundheaded bark-borer. (Original.) 



those in the larger patches, within 10 or 15 square miles are thus 

 treated, it should destroy enough of the broods to protect the remain- 

 ing timber for several years. If, then, this practice is followed up 



