NATURAL ENEMIES OF THE FOREST. 



245 



develop in the wood of a tree without affecting its life but the wood Is ren- 

 dered worthless for most purposes by the so-called wormhole and pinhole 

 defects resulting from their burrows. The same species also breed in the 

 wood of dying and dead standing trees, and in the stumps and logs of felled 

 ones, often for many years after the trees are felled. One species sometimes 

 attacks freshly sawed oak lumber, new stave bolts, etc. They are among 



the most destructive ene- 

 mies of hardwood forest 

 trees, especially in rer 

 ducing the value of the 

 wood of the best part of 

 the trunks. ( Hopkins, 



Fig-. 96. Work of Powder Post Beetle, Sinoxylon basi- 

 lare, in hickory pole: a, Character of work by larvae; 

 , Exit holes made by emerging- broods. r 



Book, 1904, Fig. 49.] 



[ Agric. Tear 



Forestry Bulletin No. 48, 



p. 10.) 



The carpenter worms, 



Fig. 98. These are large 



pinkish caterpillars which are the larvae of stout-bodied moths. They enter 

 the bark and wood of living oak, locust, poplar and other trees, from eggs 

 deposited by the moths in the crevices of uninjured bark, or in the edges of 

 wounds. They burrow deep into the solid wood, where they live for two or 

 three years before transforming to the adult. The wood is seriously injured 

 by the very large wormhole defects, and while the life of the tree is but 

 slightly, if at all, af- 

 fected by the earlier at- 

 tacks, the continued 

 operations of this class 

 of borers year after year, 

 finally results in the de- 

 cay of the heart-wood, or 

 a hollow trunk and a 

 dead top. (Hopkins, 

 Forestry Bulletin, No. 

 48, p. 11.) 



Columbian Timber- 

 beetle. One of the com- 

 monest wormhole defects 

 in white oak, rock oak, 

 beech, and tulip ("white- 

 wood" or "yellow pop- 

 lar") is one known to 



the lumber trade as grease spots, patch- worm, or black holes, Fig 99, steam 

 boats, Fig. 100, etc., caused by the Columbian timber beetle (Corthylus co- 

 lumUanus Hopk.) The characteristic feature of this wormhole defect, which 

 will enable it to be readily recognized in oak and beech, is transverse series 

 of two or more black holes about the size of the lead in an ordinary lead 

 pencil, with a streak of stained wood extending with the grain two or three 

 or more inches each side, as in Fig. 99. In quarter-sawed oak or split or 



Fig. 97. Work of Timber Worms in 

 Oak: , Work of oak timber worm, 

 Eupsalis minuta; b, Barked surface; 

 c, Bark; </, Sap-wood timber worm, Hy- 

 tocaetus Ingubris, and its work; e. Sap- 

 wood. [Agric. Tear Book, 1904, Fig-. 47, 

 p. 386.] 



