458 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



during the winter, several generations are doubtlessly produced in a 

 season. 



More important than the ambrosia beetles are the deep-wood borers, 

 — the Cerambycid and Buprestid beetles, — whose larvae make large 

 burrows deep into the wood. 



The destructive ''Sawyer" {Monohammus titillator) of the Southern 

 States seems not to be present in the Black Hills. The chief damage 

 is done by the larva of a Buprestid beetle, probably the Heartwood 

 Pine Borer (Chalcophora virginiensis) or one of its western forms 

 oregonensis, or angulicollis montana. The three forms mentioned do 

 not differ materially. All are large metallic lustered, bronze colored 

 beetleS; about an inch long and a quarter of an inch wide. They fly 

 with a distinct buzzing sound. 



The larvse are elongated, whitish, flatheaded, legless grubs. The 

 head is yellowish to brownish, and armed with strong jaws, which 

 can be heard as it excavates in its burrow. The length at maturity 

 is an inch and a half or more. 



The adults fly in July, during the third week of that month the 

 woods are full of them, but by the end of the first week in August 

 all seem to have disappeared. The flying season probably lasts from 

 the middle of June to the last of August at the outside. 



The eggs are layed in holes cut in the bark by the female, occasion- 

 ally in living, more often on recently dead trees. They hatch in a 

 few days, and for a few weeks bore in the bark. Under favorable 

 circumstances they may enter the wood within a month; by the end of 

 two months, if conditions are favorable, they may have bored into it 

 for two inches. The larval stage lasts till the following season, and 

 may last for two years. Their activity does not continue after cold 

 weather sets in, and the wood freezes. 



Character of Insect Damage. Ambrosia beetles aid in bluing fire- 

 killed timber, but it is seldom that the sapwood escapes bluing even 

 without their assistance. If timber is cut before it is badly infested 

 by the larger borers, the work of the ambrosia beetles is usually re- 

 moved with the slabs. 



The larger borers if abundant will in time completely riddle a log, 

 so that it is worthless save as firewood. In a single season they may 

 reduce its value from thirty to fifty percent. 



Effect of the Season of the Fire. The severity of attack by boring 

 insects varies with the season of the fire. It can of course take place 

 immediately after one only during the season when the adults are 

 flying. The further removed from this period the fire comes the less 

 will be the strength of the beetle attack, since the wood has more 

 •chance to dry out and the bark to become detached. 



