INSECTS AFFECTING FOREST TREES. 



523 



Description. The beetle varies in color from a light brown to black, is a very lit- 

 tle over y^(, of an inch long and relatively stout. The mouth parts are tipped with 

 black. The eyes are black, coarsely granulated, transversely elongated and partly 

 divided near their middle. The prothorax is rather coarsely and thickly punctured 

 and tapers very much anteriorly. The wing covers or elytra are margined 

 anteriorly, deeply striate and thickly clothed with short, yellowish hairs. 



A pupa nearly ready to assume the adult form is yellowish white, about the 

 length of the beetle and stouter. The eyes are a brown and the mouth parts almost 

 black. Four of the abdominal segments project beyond the wing pads. 



The typical burrow, figures 25, 26, and plate io„ figure 3, has a very characteristic 

 form. From the three lobed primary or entrance chamber a broad burrow about -^^ 

 of an inch long runs nearly parallel with the wood fibers. Eggs are laid in minute 

 notches on botji sides of the primary channel and the )-oung Avork for a short 

 distance at nearly right angles and then they are apt to take an oblique direction. 



FIG. 25. PHLAEOSINUS DENTA TUS 



ADULT GALLERY AND EGG NOTCHES. ORIGINAL. 



FIG. 26. PHLAEOSINUS DENTA TUS 



SMALL GALLERY AND LARVAL MINES. ORIGINAL. 



The larval burrows score the sap wood lightly at first but as the grubs increase in 

 size the wood is entered more deeply, till nearly half the burrow may be in the 

 wood. 



Natural Eiicviics. This little insect appears to be kept well in check by natural 

 enemies, of which a number have been recorded. Dr. Hopkins states that the pre- 

 daceous Cyniatodcra bicolor Say, and Clcriis quadrisignatus Say, var. nigripcs Say, 

 have been observed under red cedar bark with this insect. Several small parasites 

 also prey upon this species. Spathiiis canadensis Ashm., a species of Ptcroinalus and 

 a species of Eiirytoina have been observed by Dr. Hopkins preying upon this borer. 

 The writer has reared another small parasite from this insect, which has been kindly 

 determined by Mr. Ashmead as Caudonia pityophthori Ashm. MS. 



