THE GOAT-MOTH 



65 



this or any other insect-pest, if there are no other breeding- 

 grounds close at hand. It is possible to find and destroy 

 the pupae, which lie up on palings, walls, and similar objects. 

 A quick eye is needed to distinguish them, and unless their 

 places of shelter are scrupulously searched at frequent intervals 

 they become safe retreats instead of traps, and should be 

 abolished as far as possible. No means of extermination 

 that man can devise is nearly so effectual as the ichneumons, 

 an account of which is given in Lesson 22. In certain 

 years so large a proportion of the larvse are ichneumoned 

 that for some years afterwards the cabbage whites are com- 

 paratively few. In this, as in other cases of insect attacks, 

 liberal feeding may help the crop over the time when it 

 is most liable to serious injury. 



16. THE GOAT-MOTH (Cossus ligaiperda) 



The caterpillars of the goat -moth are very destructive 

 to standing timber, devouring the wood of healthy trees of 



Fig. 48.— Goat-moth (female). After Roesel von Rosenhof. 



many sorts. They are most commonly met with on the 

 willow and poplar, but the damage which they do to oaks 

 causes the most serious loss. 



The female is a large, thick-bodied moth of brown and 

 grey colours, from 70 to 90 mm. across the expanded wings ; 

 the male is decidedly smaller. The fore wings are long, 

 and marbled or mottled with black and white; the hmd 

 wings are short, rounded, and nearly uniform in colour. The 



