146 



Insects and Diseases. 



Fig. 179. Apple-tree Borer. 



The perfect insect is a brown and white striped beetle (Fig. 179), 

 about three-fourths of an inch long, which flies at night. It deposits 

 its eggs late in spring or the first of sum- 

 mer, in the bark near the surface of the 

 ground, and sometimes in the forks of the 

 branches. The first indication of its pre- 

 sence is the appearance of numerous 

 small round holes, as if the bark had been 

 perforated by buck-shot. These holes 

 will soon become more visible by the 

 ejected dust. 



Dr. Fitch gives the following d r stinct 

 account of this insect in the Illustrated 

 Annual Register : 

 " The beetle comes abroad in June, and drops its eggs under the 

 loose scales of the bark, low down near the surface of the earth. 

 The worm which hatches therefrom eats inward through the bark, 

 till it comes to the wood. It there remains, feeding upon the soft 

 outer layers of the wood, and thus excavating a shallow round 

 cavity under the bark, the size of a half-dollar ; though wheie two, 

 three, or more worms are lodged in the same tree, as they always 

 preserve a narrow partition between their cells, one never gnawing 

 into that of another, these cells by crowding upon one another 

 become of an irregular form, and almost girdle the tree. 1 he cell 

 is always filled with worm dust, crowded and compacted together, 

 some of which becomes crowded out through a crack in tho bark, 

 or a hole made by the worm. And it is by seeing this sawdust-like 

 powder protruding out of the bark, that we detect the presence of 

 these borers in the tree. The worm continues to feed and enlarge 

 its cell under the bark for about twelve months, until it has become 

 half grown and is from a half to three-fourths of an inch in length. 

 Its jaws have now acquired sufficient strength for it to attack the 

 solid heart wood of the tree, and it accordingly bores a cylindrical 

 hole from the upper part of its cell, upward in the solid wood, to a 

 length of three or four inches or more, this hole inclining inwards 

 towards the centre of the tree, and then curving outwards till its 

 upper end comes again to the bark. It then stuffs the upper end 

 of this passage with fine chips or worm dust, and its lower end with 

 short fibres of wood, arranged like curled locks of hair, thus form- 

 ing an elastic bed on which to repose during its pupa state. These 

 operations being completed, it throws off its larva skin and becomes 

 a pupa, usually at the close of the second summer, or about fifteen 



