154 SPHIKG. 



perfect certainty, but it is exceedingly probable, as the 

 white ones are turned up by the plough as early as 

 the middle of January, while they are not found in 

 the air till May, or the end of April, a little sooner or 

 later, according to the season. 



It is inconsistent with the general practice of 

 nature that an insect which has thus always a store 

 of at least four generations in the earth, should be 

 without a number of destroyers, because its numbers 

 would otherwise accumulate, not only in an undue 

 proportion, but in such a manner as to destroy the 

 succession of its own means of subsistence. When 

 in the air it has many enemies, and when in the 

 earth it has none more general or more efficient than 



THE ROOK. 



The whole of the CROW tribe (the COR v us of Lin- 

 naeus), are of great service in the destruction of 

 noxious insects and disagreeable substances ; and 

 though they often commit depredations of a different 

 and even of a serious kind, probably the good that is 

 done by the whole race more than counterbalances 

 the evil ; and experience has shown that with the 

 rook this is really the case. There is no need of a 

 minute description of the personal appearance, or even 

 of the more remarkable habits, of the animal; for, 

 unless in those desolate and upland parts which they 

 do not frequent, there is hardly any body that has 

 not seen a rook, and their nests are often met with 

 in cities, if there happen to be a few tall trees ; and in 

 those places of Britain which the rook does not fre- 

 quent, the carrion crow or the hooded crow (if these be 



