4 INSECTS INJURIOUS TO FORESTS. 



their work, is reddish to dunnish yellow in color and has a claylike 

 consistency. The mines eventually end in a broad chamber, the 

 entrance to which is plugged up by the excelsior-hke fibers of wood 

 chiseled out by the strong mandibles of the larva. Here the resting 

 stage (fig. 3), or pupa, is formed, and in this chamber the perfect adult 

 spends considerable time before emerging. Often all stages from very 

 young larvae only about one-fourth inch long to full-grown larvae over 



1 inch long, pupae, and 

 adults in all stages to 

 maturity are present in 

 the same pole. Adults 

 have been found flying 

 from July to Septem- 

 ber. As yet the sea- 

 sonal history of this 

 borer has not been com- 

 pletely worked out. 



DISTRIBUTION. 



Fig. 2.— The chestnut telephone-pole borer: Female beetle, three ^ "^^ inseCt ^ IS Very 



and one-half times natural size. Head and pronotum of male widely distributed, 



beetle. (Original). ranging from Ontario, 



Canada, to Texas, eastward to the Atlantic coast, and westward to 

 Arizona and southern CaHfomia. It is common throughout the 

 natural range of the chestnut — and in this coimection it should be 

 observed that most of the chestnut poles are purchased from local 

 timber-land owners. 



CHARACTER OF THE INJURT. 



The injury to the poles consists in large mines in the wood near the 

 line of contact of the pole with the ground, necessitating the frequent 

 resetting or even the replacement of the damaged poles. These 

 irregular galleries of the grub (Plate II, fig. 1) run both transversely 

 and longitudinally throughout the heartwood, and are sometimes 7 

 inches long, but vary with the individuals, which show great differ- 

 ences in size. The borers usually work in the outer layers of the 

 wood at the base of the pole for a distance of from 2 to 3 feet below, 

 and sometimes from 1 to 2 feet above the line of contact of the pole 

 with the surface of the ground. The greatest damage is to that area 

 just below and just above the surface of the ground (Plate I, fig. 3) ; 

 here the conditions of air and moisture are most favorable. Often 

 the entire butt up to a distance of from 4 to 6 feet and higher, 

 according to the depth of setting, is mined. The numerous galleries, 

 often very close together, completely honeycomb the wood in a zone 



