INSECTS AFFECTING PARK AND WOODLAND TREES 295 



Minute oak bark beetle 

 Pityoplit horns vtinutissimns Zimm. 



A minute slender, dark brown beetle, about '/ 16 inch long, sometimes riddles the dead 

 inner b;\rk of red oaks. 



This species was found by the writer in great numbers at Manor, Oct. 

 3, 1900, mining the bark of piled red oak cord wood which was probably 

 cut the preceding winter. Dr A. D. Hopkins has recorded this species as 

 infesting black oak, white oak, jack oak, chestnut oak and dogwood, and he 

 has observed a chalcid fly attack the adults. This species has also been 

 recorded by Dr Riley as mining the dry oak bark. 



Description. The adult is a small, rather slender dark brown beetle, 

 about ■ ,„ inch long. The head is ornamented with two bunches of yellow- 

 ish, curved hairs. The prothorax is rather coarsely tuberculate and the 

 wing covers or elytra are very finely striated. Certain structual details of 

 this beetle are shown on plate 67, figure 11, and its method of work on 

 plate 39, figure i. 



The beetle runs its galleries transversely to the bark fibers, depositing 

 eggs on either side, the young hatching therefrom work at nearly right 

 angles to the parental grooves and therefore nearly parallel to the grain of 

 the wood. This insect, when present in numbers, soon riddles the bark and 

 as the numerous exit holes allow ready access to moisture, decay soon fol- 

 lows. This can hardly be considered a species of much importance, except 

 as it aids in hastening the decay of the wood, since it apparently confines 

 its operations to dead bark. 



A small beetle, Silvanus surinamensis Linn., was reared from 

 a piece of infested bark, and it was evidently living on either decaying 

 vegetable or animal matter, rather than preying on this bark borer. 



Bibliography 

 1893 Hopkins, A. D. W. Va. Agric. Exp. Sta. Bui. 32, p. 208, 228 



