INTRODUCTION. 75 



Instances of their depredations are indeed of such 

 ordinary occurrence as to have fallen under the 

 observation of almost every one, and absolve us from 

 any necessity of giving many details on the subject. 

 Perhaps the species which have proved most in- 

 jurious to the produce of our fields in this country, 

 are those of the Brown-tail-moth (Porthesia auri- 

 flua, Steph., Bom. phceorrhoea, Curtis. Don.), the 

 Gamma-moth (Plusia gamma), the Antler-moth 

 (Charceas gramims), the Lackey (Clisiocampa 

 neustria), the Buff-tip (Pygcera bueephala), the 

 Cabbage-moth (Mamestra BrassicceJ, the small 

 Ermines ( Yponomeuta), and a few others. The first 

 mentioned of these increased to an extraordinary 

 degree in several parts of England in the summer 

 of 1782, and by completely defoliating the trees, 

 occasioned such alarm that prayers were ordered to 

 be read in the churches to avert the calamity. It 

 was apprehended, by those ignorant of their history, 

 that these caterpillars would likewise destroy the 

 growing corn and grass ; but it was soon shown that 

 the leaves of trees and shrubs form their only food, 

 and that these valuable productions would conse- 

 quently escape their attack. So numerous were 

 these creatures, that subscriptions were opened in 

 many parishes, and poor people employed to cut off 

 the webs at the rate of a shilling a bushel, which 

 were burned under the inspection of the overseers 

 of the parish; and it is stated that no less than 

 fourscore bushels were for a while collected daily in 



