430 INSECTS AT HOME. 



ptera ^-enerally are quiescent, and few can do more than jerk 

 the tail from side to side when irritated, it is rather startling 

 to see a chrysalis wriggle itself up and down the burrow which 

 it has made while in the caterpillar state. 



We now come to the Goat Moth {Cossus ligniperda), 

 so-called on account of the very strong odour which is given 

 out by the larva, and bears some resemblance to the powerful 

 scent of the he-goat. A figure of this insect is given on 

 Woodcut XLV. Fig. 2. 



The colour of this Moth is nothing more than brown of 

 different shades, arranged as shown in the illustration. As far 

 as the perfect insect goes, there is but little interest about it, 

 but in the larval condition it is peculiarly interesting, were it 

 only for the fact that everything which can do harm contains 

 within itself an element of interest. We will rapidly trace the 

 life of the Goat Moth, from the deposition of the egg to the 

 development of the perfect insect. 



It has already been mentioned that the female JMoths of this 

 family possess a long ovipositor. With this instrument the 

 female Goat Moth carefully lodges her eggs deeply in the crevices 

 of the bark of some tree, and there leaves them. In process of 

 time they are hatched, and, tiny as they are, soon are able to 

 bore their way into the tree. They spend four years in the 

 body of the tree, apparently never ceasing to eat, and boring 

 their tunnels through and through the solid wood. These 

 tunnels increase in size according to the development of the 

 caterpillar, and, as a great number of larvae generally inhabit 

 one tree, it is no wonder that so many trees are killed by 

 them. 



The number of these destructive creatures that are found in 

 one tree may be imagined from an experiment made by Mr. 

 Douglas. He found an elm lying on the ground, having been 

 blown down in consequence of the galleries of the Goat Moth 

 caterpillar weakening the trunk so much that it could not 

 endure the wind. He cut off a piece of the trunk two feet 

 long, and twenty-three inches in diameter at one end and 

 fifteen at the other. Wishing to place it in a vessel sixteen 

 inches in diameter, he was obliged to cut it to the required 

 size, and in so doing turned out no less than sixty-seven 



