OBJECTIONS ANSWERED. 31 



the web-like nests which so often deform our fruit 

 trees, without suspecting that new armies of assailants 

 will wander from those on other plants which they 

 have suffered to remain. Thus will thousands be pro- 

 duced in the following season, which, had they known 

 how to distinguish them, might have been extirpated. 

 Another instance occurred to me last year, when walk- 

 ing with a gentleman in his estate at a village in York- 

 shire. Our attention was attracted by several circu- 

 lar patches of dead grass, each having a stick with rags 

 suspended to it, placed in the centre. I at once dis- 

 cerned that the larva of the cock-chafer had eaten the 

 roots of the grass, which being pulled up by the rooks 

 that devour this mischievous grub, these birds had 

 been mistaken by the tenant for the cause of the evil, 

 and the rags were placed to frighten away bis best 

 friends. On inquiry why he had set up these sticks, he 

 replied, " He could n't beer to see'd nasty craws pull 

 up aird gess, and sae he'd set'd bairns to hing up some 

 aud clouts to flay 'em away. Gin he'd letten 'em alean 

 they'd sean hev reated up all'd close." Nor could 1 

 convince him by all that I could say, that the rooks 

 were not the cause of the evil. Even philosophers 

 sometimes fall into gross mistakes from this species of 

 ignorance. Dr. Darwin has observed, that destroying 

 the beautiful but injurious wood-peckers is the only 

 alternative for preventing the injury they do to our 

 forest-trees by boring into them'; not being aware 

 that they bore only those trees which insects have previ- 

 ously attacked, and that they diminish very considerably 

 the number of such as are prejudicial to our forests. 



' PhytGlogia, 518. 



