352 



YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. 



in the heartwood or even in the bark. It appears probable that 

 the winter may be passed either in the larval, pupal, or adult stage, 

 the larval stage evidently predominating. The period during which 

 adults emerge is quite extended, apparently from March to Septem- 

 ber, inclusive, depending considerably on latitude and altitude and 

 on the stage of development reached before hibernation began during 

 the previous winter. The same period represents the time when eggs 



are deposited for another gen- 

 eration. 



The usual preventive measures 

 are recommended, i. e., remov- 

 ing the bark from trees when 

 felled or treating rustic work 

 as recommended for the black- 

 horned pine borer, except those 

 felled in late fall or early winter, 

 which should not be injured by 

 this borer. 



THE WESTERN CEDAR BARK-BORER. 



(Hylotrupes amethystinus Lee.) 



The western cedar bark-borer 

 is a relative of the preceding, 

 the cedar-tree borer. Unlike the 

 latter, however, its range is con- 

 siderably restricted. The rec- 

 ords of the branch of forest in- 

 sect investigations, Bureau of 

 Entomology, indicate that it is 

 found only in the Pacific Coast 

 States. It is of considerable eco- 

 nomic importance, however, in 

 injuring the bark and wood of 

 recently felled giant arborvitae 

 and incense cedar. 



The larva (fig. 25, a) is a 

 large, fleshy, yellowish-white grub, provided with three pairs of 

 feet. The largest larvae are about 25 mm. long at maturity and 

 about 8 mm. in width at the broadest part of the body, the pro- 

 thorax. The adult (fig. 25, b) is a medium-sized to large, robust 

 beetle, 12 to 23 mm. in length. The prothorax is black to reddish 

 brown. The elytra, or wing-covers, are of a brilliant blue to vio- 

 let color. The larvae mine in the inner bark, making broad wind- 





FIG. 25. Work of the western cedar bark- 

 borer. (Hylolrupes amethystinus). Sec- 

 tion of incense cedar log, showing larval 

 mines, a, Larva; 6, adult; e, entrance 

 hole of larva into wood. Insects slightly 

 reduced from natural size. (Original.) 



