MARCH 71 



' Owing to the great numbers in which the species of BiUonidce 

 sometimes appear, these insects have been supposed to be very 

 injurious. Careful inquiry, however, exculpates them as doers 

 of serious injury, though Dilophus febrilis, a so-called fever fly, 

 appears to be really injurious in this country when it multiplies 

 excessively, by eating the roots of the hop-plant.' 



Rooks cannot help us against Dilophus, as the grubs 

 are beyond their reach. 



Lastly the corn-ground beetle Zabrus belongs to a 

 fiercely predaceous family, which, both as larvce and 

 perfect insects, attack worms, grubs, and soft-bodied 

 insects. It is true that Zabrus sometimes feasts on 

 growing corn, but so does the rook itself. 



It is evident, I think, that Dr. Hollrung has failed to 

 re-establish the rook's character in relation to agriculture ; 

 indeed he concludes his report with some observations 

 highly creditable to his impartiality. While claiming for 

 them approval for their diligence in hunting up insect 

 pests, he admits that they are omnivorous ; that they are 

 harmful to game preserving from their partiality for eggs ; 

 that ' in the neighbourhood of rookeries the harm done 

 easily outweighs the good ' ; that their numbers should be 

 kept within reasonable limit, and that farmers ought to 

 co-operate to that end. 



Our own Board of Agriculture, in noticing in their 

 journal for last October Dr. Hollrung's report, strongly 

 support this recommendation; and the necessity for 

 judiciously repressive measures is enforced by Mr. J. 

 Sparrow Worth in a letter to the Field newspaper of 

 8th December 



' Within the last few years I have killed some thousands, a 

 great many of which I have opened and examined, and have 



