ORCHARD INSECTS 291 



Fig. 208, while the male scale is much smaller, snowy 

 white, and with three distinct ridges. The life history is 

 similar to the last species and it is controlled by the same 

 means. 



154. The Fruit-tree Bark-beetle.* The fruit-tree bark- 

 beetle (4, 41), is often known as the "shot-hole borer" from 

 the fact that an affected tree looks as if it had been struck 

 with a charge of bird shot. More or less gum often exudes 

 from these holes on stone fruits. Injury is largely due to 

 allowing dead and dying trees to stand in or near the orchard, 



a 6 c d ^ 



FIG. 209. The fruit-tree bark-beetle (Scolytus rugulosus}. (After 

 Chittenden, U. S. Dept. Agr.) 



a, b, beetle; c, pupa; d, larva enlarged. 



as such trees are most subject to attack, and healthy trees are 

 not usually injured in well-cared-for orchards. The holes 

 are caused by the exit of the small parent beetles and the 

 entrance of the females to lay then- eggs. The beetle is 

 about one-tenth inch long, and of a black color, except the 

 tips of the wing-covers and parts of the legs, which are red. 

 The beetles emerge in the spring. Between the bark 

 and the sap-wood the females eat out small burrows along 

 the sides of which the eggs are laid. The larvae excavate 

 little side-galleries which branch out and widen as they in- 

 crease in size. They become full grown in about three 

 * Scolytus rugulosus Ratz. Family Scolytidce, see page 127. 



