18S INSECTS AT HOME. 



coin])letely through the bark, until she gets between the bark 

 and the solid wood. She next drives a tunnel, scarcely wider 

 than her own body, and then goes back along the tunnel, and 

 deposits her eggs along it. In many cases she exhausts all her 

 life-powers in the effort, and dies before she can entirely escape 

 from the burrow, the entrance of which is stopped up by her 

 body, so that no foe can enter. 



The eggs are soon hatched, and then the larvae begin their 

 destructive work. They feed on the soft inner bark, and each 

 larva, as it feeds, instinctively turns itself at right angles to the 

 burrow in which it was hatched, and gnaws for itself a tunnel, 

 which widens in proportion to the growth of the larva. These 

 burrows extend for an inch and a half or two inclies in length, 

 and the result is, that a piece of bark, some three inches or 

 more in diameter, is completely severed from the tree and can 

 no longer perform its office. At the widened end of the burrow 

 the larvae ass une the pupal form, and, after undergoing their 

 change into tlie perfect insect, gnaw their way through the 

 bark, and are ready to lay the foundations of new colonies. 



When a great number of these insects bore into a tree, they 

 often destroy it entirely, the bark being separated as com- 

 pletely from the wood as turf is severed from the ground when 

 the spade is passed under it. There is a tree — or rather, what 

 was a tree — standing within a few yards of my house, which 

 has been killed by the Scolytus. The whole of the bark has 

 peeled off, and nothing is left but the naked wood, scored all 

 over with the radiating tunnels of the destroying insect. 



Should the reader wish to examine this insect for himself, 

 he will find no difficulty in so doing. He has only to visit any 

 place where elm-trees grow, and he is nearly sure to find the 

 Scolytus under the bark. August is perhaps the best time for 

 the purpose, as then the perfect insects, the larvae, and the 

 pupae can be discovered. The larva is white, thick, and fleshy, 

 the back is deeply wrinkled — probably to aid the creature in 

 forcing its way through the wood, this being an absolute con- 

 dition of existence. It cannot remain in the same place, 

 because it grows so fast that the unyielding substances around 

 would not permit its increase in size, and it woidd in conse- 

 quence soon perish. It is forced, therefore, to push itself 

 onwards, and to occupy the space which was originally filled 



