66 GRAMMAR OF ENTOMOLOGY. 



CHAPTER XIII. 



HISTORY OF THE HOP-FLY.* 



Class Hemiptcra. i Genus Aphis. 



Order Aphitcs. I Species Humuli. 



206. The crop of hops is entirely dependent 

 on a little, and apparently insignificant fly, well 

 known to hop growers under the name of the 

 hop-fly. 



207. The duty on hops is a considerable source 

 of revenue to the British Government : when the 

 hop-fly has been unusually numerous, the whole 

 duty on hops throughout the kingdom has amounted 

 only to 15,000Z. ; when, on the contrary, the fly 

 has not appeared, the duty has been 468,000^ : 

 this little insect thus appears capable of abstracting 

 from the British treasury 453,000?. per annum. 



208. The duty, 18s. 8d. per cwt., is but 

 about a sixth part of the value of hops ; so that 

 the real sum over which this little creature exer- 

 cises its influence is at least 2,700,000/. per 



* RnsTicvs, in the Entomological Magazine. 



