OBJECTIONS ANSWERED. 29 



recommended that they should be encouraged as friends 

 to 1 man, since no insects are greater devourers of the 

 Aphides. The confounding of the apple Aphis (A. lani- 

 gera, Myzoxyla ? a ) that has done such extensive injury 

 to our orchards, with others, has led to proceedings still 

 more injurious. This is one of those species from the 

 skin of which transpires a white cottony secretion. Some 

 of the proprietors of orchards about Evesham, observing 

 an insect which secreted a similar substance upon the 

 poplar, imagined that from this tree the creature which 

 they had found so noxious was generated ; and in con- 

 sequence of this mistaken notion cut down all their pop- 

 lars 5 . The same indistinct ideas might have induced 

 them to fell all their larches and beeches, since they also 

 are infested by Aphides which transpire a similar sub- 

 stance. Had these persons possessed any entomological 

 knowledge, they would have examined and compared the 

 insects before they had formed their opinions, and being 

 convinced that the poplar and apple Aphis are distinct 

 species, would have saved their trees. 



But could an entomological observer even ascertain 

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

 without further information, he may fall short of his pur- 

 pose of prevention. Thus we are told that in Germany 

 the gardeners and country people, with great industry, 

 gather whole baskets full of the caterpillar of the destruc- 

 tive cabbage moth (Mamestra Brassic<z\ and then bury 

 them, which, as Roesel well observes , is just as if we 

 should endeavour to kill a crab by covering it with wa- 

 ter ; for, many of them being full grown and ready to 



a See Latr. Families Naturelles du Regne Animal, 429. 



b Collet, in Month. Mag. xxxii. 320. c Roesel I. iv. 170. 



