444 Mr. Macleay on the. devastations 



that this tendency of the Mice to cat tlie bark of young trees, 

 had heretofore been observed there. 

 I have the honour to be, 

 Dear Sir, 

 With sincere respect and esteem, 

 Your very faithful and obliged humble servant, 



Glenbervie. 



Art. LVI. Remarks on the devastation occasioned hy the 

 Hylohius ahietis in Fir Plantations^ bj/W. S. MacLeay, 

 Esq. A.M. F.L.S. <Sc 



[In a letter addressed to the Conductors of the Zoological Journal, 

 4th Dec. 1824.] 



Gentlemen, 



I HAVE attentively perused, at your request, the late Lord 

 Glenbervie's very interesting letter to Sir Joseph Banks, on the 

 important subject of the mischief done to the Royal forests in the 

 years 1813 and 1814; and I think that no reader of the details 

 there so clearly given can be otherwise than convinced that his 

 Lordship has concluded rightly, that the principal cause of the 

 mischief was the unexampled multitude of Mice which then infested 

 these forests. In addition to the strong arguments by which his 

 Lordship proves that the destruction was effected by Mice, the fol- 

 lowing may be given as almost conclusive to the point that it was 

 not effected by insects. Herbivorous insects, and especially those 

 which are intended by nature to keep vegetable luxuriance within 

 due bounds, have, I believe, been invariably found to affect parti- 

 cular species of trees, attacking them in different ways according 

 to their peculiar economy. Now Lord Glenbervie mentions that 

 the Hollies and Oaks, the Ash, Chesnut, Beech, &c. and, " as 

 has been lately observed, even Larch and Fir,^'* have been 



* From the manner in which the attack on the Larch and Fir is mentioned, 

 the cause of it may have been different, perhaps the Hylobius abietis. 



