NATURAL ENEMIES OF THE FOREST. 



243 



Fig-. 91. Brood Galleries of 

 the Oak Hark Beetle, showing- 

 Character of Primary Gallery 

 at b; Larval or Brood Mines a"t 

 a. \Agric. Tear Book, 1903, Fig-. 

 30, page 318.] 



Pig-. 92. Work of Ambrosia Beetle, 

 Xyloborus celsns, in Hickory Wood: a, 

 Larva; />, Pupa; c, Adult beetle; d. Char- 

 acter of work in' lumber cut from in- 

 jured log-; .', Bark;/, Sap wood; g. Heart- 

 wood. \_Affric. Tear Book, 1904, Fig-. 44, 

 P.384.J 



There are two general types or classes of 

 these galleries, one in which the broods de- 

 velop together in the main burrows, the other, 

 in which the individuals develop in short 

 separate side chambers extending at right 

 angles from the primary gallery, Fig. 93. 

 The galleries of the latter type are usually 

 accompanied by a distinct staining of the 

 wood, while those of the former are not. 

 (Hopkins, Agric. Yr. Bk., 1904, p. 383.) 



Bark and ivood borers, Fig. 94. This 



class of enemies differs from the preceding in the fact that the parent beetles 

 do not burrow into the wood or bark, but deposit their eggs on the surface. 

 The elongate, whitish, round-headed ( Cerambycid ) , flat-headed (Buprestid), 

 or short, stout (Curculionid) 

 grubs hatching from these 

 eggs cause injury by bur- 

 rowing beneath the bark, or 

 deep into the sap-wood and 

 heart- wood of living, in- 

 ]ured and dead trees, saw- 

 ]ogs, etc. Some of the spe- 

 cies infest living trees, Fig. 

 95, causing serious injury 

 or death. Others attack 

 only dead or dying bark and 

 wood, but this injury often 

 results in great loss from 

 the so-called wormhole de- 

 fects. (A. D. Hopkins, 

 Entom. Bull, No 48. p. 10.) 



Fig-. 93. Wcrk of Ambrosia Beetles in 

 Oak: a, Monarthum mali, and work; 

 b, Platypus compositus, and work; c, 

 Bark; ~d, Sap-wood; e. Heart-wood; /", 

 Character of work in lumber from in- 

 iured log-. [Agric. Tear Book, 1904, Fig-. 

 *45, p. 384.] 



