THE PAINTED HICKORY BORER 193 



distinct or else cross each other in places. Prom beginning to end, however, 

 all the galleries increase in width and depth, until, just before the pupal 

 cell is formed, they measure from J to J inch wide and J inch in depth. 

 In small branches, in which a large number of larvae are at work, the 

 sapwood may be entirely honeycombed to a depth of an inch or more, 

 the different burrows being indistinguishable from each other. The 

 nature of the wood seems also to have a decided influence on their shape, 

 those in wood free from knots being more or less regular and linear, while 

 those in knotty material may be very irregular. On felled material, the 

 galleries may extend in either direction with the grain of the wood, but 

 in standing timber the majority of them first extend downward. 



The burrows are firmly packed with the coarse, sawdust-like borings 

 chewed off by the larvae, whose gnawings can be heard for a considerable 

 distance and resemble the noise made by the so-called " sawyers " in pine. 

 The writer was unable to determine whether all of the gnawed material 

 passed thru the body of the larvae. That dissections showed the alimen- 

 tary canal full of sawdust-like particles, and that the material filling the 

 burrows was so tightly packed and stuck together that it took considerable 

 work to dislodge it, are facts tending to confirm this view. Furthermore, 

 it is not easy to see how the larvae could store the loose sawdust so 

 compactly, were it not previously moistened by passage thru the alimen- 

 tary canal. Here and there along the course of the burrows, air holes 

 are eaten thru the bark to the exterior, the number of these for a single 

 burrow varying from one to four. 



The pupal cell 



The larva becomes full grown in from ten to twelve weeks. At the 

 end of that time it gnaws a large, oval-shaped hole thru the bark to the 

 exterior, and begins the construction of the pupal cell. This extends 

 into the solid wood to a depth of from i to 2\ inches, and then parallel 

 with the grain of the wood for about 2 inches. In making the pupal 

 cell, the larva apparently does not eat the sawdust, for as soon as an 

 appreciable amount is chewed off, the larva, using its head as a scraper, 

 pushes it to the exterior thru the hole previously made in the bark. After 

 pushing out one load, the larva backs down into the burrow again and soon 

 reappears with another supply. This process is continued until the entire 

 pupal cell is completed. Evidence of the borer's attack on timber is 

 therefore seen at this time in the large, oval holes in the bark and in 

 the great amount of sawdust pushed out, which accumulates in small 

 heaps beneath infested material. The making of large holes thru the bark 

 before pupating seems rather unusual, as many of the Cerambycid larvae 



