146 THE SCOLYTID BEETLES. 



It is evident that the price of cleaning becomes then very high; but we are com- 

 pensated by preserving precious trees to continue the existence of the planting. 



In conclusion, we counsel, therefore, repeated visits during the summer months in 

 the forests where the presence of D. micans has already been determined and in those 

 where it may be expected; then, visits less frequent during the months of spring and 

 winter. We counsel, also, the assembling of all the official personnel of the forest 

 service as soon as the presence of the insect is found and the giving of instruction as 

 to the characteristic appearances attended by the insect attack. If necessary, a bounty 

 might be paid. 



After examining the trees designated, the foresters will decide whether it is best to 

 cut down the trees or clean them. 



In this maimer it will be everywhere as in Herzogenwald, where a rigorous sur- 

 veillance, but not at all expensive, has rendered the existence of the insect almost 

 impossible. 



SPECIMENS. 



This species is represented in the forest-insect collection of the 

 Bureau of Entomology by 90 specimens, including adults, larvae, 

 and work. 



BIBLIOGRAPHY. 



Ratzeburg, 1839 (under Sylesinus (Dendroctonus) micans), p. 217; Stein, 1854, 

 (under Hylesinm micans), pp. 277-279; KoUar, 1858, pp. 23-28; Eichhoff, 1881, pp. 

 125-128; Altum, 1881, pp. 262-266; Judeich u. Nitsche, 1889, pp. 458-462; M6n6gaux 

 et Cochon, 1897, pp. 206-209; Severin, 1902, pp. 72-81, 145-152; Weber, 1902, p. 108; 

 Brichet et Severin, 1903, pp. 244-258; Baudisch, 1903, pp. 151-152; Quairifere, 1904-5, 

 torn 11, pp. 626-628, torn 12, pp. 183-186; Qui^vy, 1905, pp. 334-335; Ntisslin, 1905, 

 pp. 175-178; Severin, 1908, pp. 1-20; Hopkins, 1909, pp. 143-146. 



No. 22. THE BLACK TURPENTINE BEETLE. 

 {Dendroctonus terebrans Oliv. Figs. 95, 96.) 



The black turpentine beetle is a large, stout, dark-brown or black, 

 cylindrical barkbeetle, 5 to 8 mm. in length, with broad prothorax, 

 coarsely punctured pronotum, the sides slightly narrowed toward 

 the head, but not strongly constricted; the elytra with coarse, trans- 

 verse to .oblique rugosities between distinct to obscure rows of punc- 

 tures; the declivity convex, with moderately deep grooves, the 

 intervening spaces slightly convex and roughened, and the entire 

 body sparsely clothed with long hairs. (See fig. 95.) It attacks the 

 living bark, usually at the base of injured, dying, or healthy trees, or 

 the stumps of felled pine and spruce, from Long Island, N. Y., south- 

 ward to Florida and westward to Texas and West Virginia, but it is 

 more common in the South Atlantic and Gulf States. The parent 

 beetles excavate broad, somewhat irregular, winding, longitudinal 

 or sometimes transverse egg galleries through the imier bark and 

 groove the surface -of the wood. The eggs are placed in groups or 

 masses at intervals along the sides of the galleries. The stout, yel- 

 lowish-white, cylindrical larvae, with reddish heads and stout spines 



