so OBJECTIONS ANSWERED. 



the species of any noxious insect, still in many cases, 

 without further information, he may fall short of his 

 purpose of prevention. Thus we are told that in Ger- 

 many the gardeners and country people, with great 

 industry, gather Avhole baskets full of the caterpillar 

 of the destructive cabbage moth {Noctua Brassicce, 

 Fab.) and then bury them, which, as Roesel well ob- 

 serves % is just as if we should endeavour to kill a crab 

 by covering it with water ; for, many of them being full 

 grown and ready to pass into their next state, which 

 they do underground, instead of destroying them by 

 this manoeuvre, their appearing again the following 

 year in greater numbers is actually facilitated. Yet 

 this plan applied to our common cabbage caterpillar, 

 which does not go underground, would succeed. So 

 that some knowledge of the manners of an insect is 

 often requisite to enable us to check its ravages eftec-r 

 tually. With respect to noxious caterpillars in gene- 

 ral, agriculturists and gardeners are not usually aware 

 that the best mode of preventing their attacks is to de- 

 stroy the female fly before she has laid her eggs, to do 

 which the moth proceeding from each must be first 

 ascertained. But if their research were carried still 

 further, so as to enable them to distinguish the pupa 

 and discover its haunts, and it would not be at all diffi- 

 cult to detect that of the greatest pest of our gardens, 

 the cabbage butterfly, the work might be still more ef- 

 fectually accomplished. Some larvae are polyphagous, 

 or feed upon a variety of plants ; amongst others that 

 of the yellow-tail moth {Bombj/x chrysorhcea., F.) ; yet 

 gardeners think they have done enough if they destroy 



* Roesel I. iv. ITO. 



