INSECT INJURIES TO FOREST PRODUCTS. 



387 



i juries a iv made by elongate, slender worms or larva 1 which hatch 



roni eggs deposited by the adult beetles in the outer bark, or, where 



lere is no bark, just beneath the surface of the wood. At first the 

 'oung larva 4 bore almost invisible holes for a long distance through the 



ipwood and heartwood, but as they increase in size the same holes are 



'nlarged and extended until the larvae have attained their full growth. 



icy then transform to adults and emerge through the enlarged 



itranee burrows. The work of these timber worms is distinguished 

 >m that of the timber beetles by the greater variation in the size of 



)les in the same piece of wood; also by the fact that they are not 

 )i*anched from a single entrance or gallery, as are those made by 



le beetles. 



POWDER POST BORERS. 



The character of work of this class of insects is shown in figures 48, 



r>n. and 51. The injury consists of closely placed burrows packed 



*ith the borings or a completely destro} r ed or powdered condition of 



FIG. -I*. Work of powder post beetle, Sinoxylon bastiare, in hickory poles, showing transverse egg 

 galleries excavated by the adult: a, entrance; 6, gallery; c, adnlt. Natural size (original). 



the w T ood of seasoned products, such as lumber, crude and finished 

 handle, cooperage, and wagon stock, furniture, and inside finish wood- 



a 



FIG. 49. Work of powder post beetle, Sinoxylon basilare, in hickory pole: a, character of work by 

 larvic; b, exit holes made by emerging broods. (Original.) 



work in old buildings, as well as in many other crude or finished and 

 utilized woods. This is the work of both the adults and voung'stages 



