SHOT-BORER. 33l 



one of our rarest species, although on the Continent it has 

 been recorded as occasionally doing enormous mischief to 

 various kinds both of young orchard and forest trees. 



The injury is caused by the beetles driving their tunnels, so 

 as in the case of quite young trees to partially ring them, and 

 also to clear out an inch or so of the central pith ; in the 

 older, though still far from full-grown, trees, although the 

 borings were not so regularly placed, still, from their large 

 number, they interfered with the passage of the sap and did 

 great harm. 



The first observation of its presence was sent me from the 

 Toddington Fruit-grounds on September 1st, by the Deputy 

 Superintendent, Mr. Charles D. Wise, who reported as follows : — 

 " I enclose a portion of the stem of a young Plum tree, in 

 which you will see a small beetle, which has bored its way into 

 the wood, and killed the tree. We are losing several trees 

 from the same cause." 



On examination I found that the cause of the injury was 

 the " Shot-borer" Beetle (as it is called in America). These 

 beetles are of a pitchy-brown or pitchy-black colour ; the 

 wing-cases are of a redder brown in the male than the female. 

 The fore part of the body behind the head is granulated ; the 

 wing-cases have alternate rows of fine punctures, with flat 

 spaces still more finely punctured, and rows of hairs. The 

 horns are clubbed at the ends, and, as well as the legs, of 

 some shade of yellow or reddish tint. 



The great peculiarity of these insects is the difference in 

 shape and size between the male and female (the disparity), 

 from which the beetle takes its name of dispar. The female 

 is about the eighth of an inch long, narrow and cylindrical, 

 with the thorax (the fore body) large in proportion, and raised 

 in the middle so as to make a kind of hump. The male is 

 only about two-thirds of the length of the female, and much 

 wider in proportion, and the back is flatter. The wings which 

 I examined in the female were well developed, and thickly 

 sprinkled with very short, bulbous-rooted bristles. 



The reason of the singularly rapid and complete destruction 

 of the stem of young trees attacked by these beetles was 

 plainly shown on laying open their tunnels. In the specimens 

 of these from Toddington which I examined (figured life size 

 opposite), I found that the injury began by a small hole like 

 a shot-hole being bored in the side of the attacked stem, from 

 which a tunnel ran to the pith, and a branch about the eighth 

 of an inch across ran horizontally about half or two-tliirds 

 round the stem. Sometimes this tunnel was about midway 

 between the outside and the centre, but in one instance quite 

 at the outside of the wood. From these horizontal borings 



