Some insects injurious to forests . (Original.) out upon the ground, as appears to be the case with some other moving about from the entrance of the hole in the wood to theplace where food is obtained, very distinct channels are made throughthis mass of refuse (fig. 21). This habit appears to continue until the larva is ready to pupate, when, ofcourse, it retires to the pupal cham-ber (fig. 19, c) already constructed,where it remains until the adultstage is reached. Previous to pu-pation the larva extends the galleryin the sap wood until the heartwoodis reached. As a general thing t
Some insects injurious to forests . (Original.) out upon the ground, as appears to be the case with some other moving about from the entrance of the hole in the wood to theplace where food is obtained, very distinct channels are made throughthis mass of refuse (fig. 21). This habit appears to continue until the larva is ready to pupate, when, ofcourse, it retires to the pupal cham-ber (fig. 19, c) already constructed,where it remains until the adultstage is reached. Previous to pu-pation the larva extends the galleryin the sap wood until the heartwoodis reached. As a general thing thegallery here turns in a longitudinaldirection for 2 or 3 inches, thenturns again toward the surface,giving the entire gallery a U-shapedappearance (fig. 19). Sometimesthe bottom of the U extends ashort distance into the heartwood,but as a usual thing it merely reaches it. In the bottom of the U isto be found the pupal cell. The gallery is here greatly widened andenlarged in order to accommodate the insect while going through its. Fig. 20.—The pine sawyer: Cross section of pupalcell. About natural size. (Original.) THE SOUTHERN PINE SAWYEB. 53 transformations (figs, L9, cf 20). The unfinished arm of the U isusually extended by the larva to within aboul one-quarter of an inchof the surface of the wood. When the larva pupates, the head ofthe pupa is turned toward the end of the chamber. When the pupachanges to the adult, the beetle extends the chamber to the surface ofthe wood and through the bark, if the bark is still upon the tree or
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsectp, bookyear1910
