SHOT-BORER. 187 



in the male than the female. The fore part of the body 

 behmd the head is granulated ; the wing-cases have alternate 

 rows of fine punctures, with flat spaces still more finely 

 punctured, and somewhat hairy. 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 disjyarity), 

 from which the beetle takes its name of disjiar. 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, 

 at p. 185), 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-thirds 

 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 

 other borings were taken straight up and down the stem ; 

 these might be certainly as many as four (perhaps more in 

 one stem), and were from half an inch to upwards of an inch 

 and a half long, and of these tunnels (in the pieces of stem 

 I examined), one ran along the pith, which was completely 

 cleared away. The great injury caused by these galleries 

 fully accounted for the death of the stem. 



At the time of examination, that is, on or about September 

 12th, the tunnels were filled with beetles ; w4iere the width 

 only was enough for one, the beetles were arranged in a row 

 one after another in procession, as it were ; where the tunnel 

 was a little wider (as where the pith had been cleared away), 

 they were less regularly arranged, but crowded in, so that 

 there scarcely seemed to be room for another. In one length 

 of wood of about two inches I found, as near as might be, 

 thirty beetles. The work of destruction was still evidently 

 going on, for in some instances I found that, instead of being 

 as usual black and discoloured, the sides of the tunnel or the 

 extremity were white and moist, showing the beetles were still 

 feeding. The instinct of tunnelling was so strong at the time, 



