RAVAGERS OF CROPS 237 



Aphides, to give them the varied names by which 

 they are known, are the most universal and at 

 the same time the most appallingly destructive 

 of all the insect ravagers of crops. No part of a 

 plant escapes their attack, the stem and branches, 

 leaves, fruit, and roots, all being liable to their 

 unwelcome attentions ; while the extraordinary 

 rapidity with which they multiply, render the 

 Aphides one of the most difficult pests to exter- 

 minate when once they have been permitted to 

 establish themselves upon the plant. Strictly 

 speaking, the word " Aphis " is a family term for 

 these insects, of which some one hundred and 

 eighty species are to be found in England ; and 

 in many cases a species will be found to confine 

 its attention to one particular food-plant, exer- 

 cising by its almost continuous attacks a very 

 great influence upon the growth of various crops. 

 Some species, however, may be found on 

 different food-plants at certain seasons of the 

 year; thus the Hop Aphis, which is responsible 

 for such appalling destruction in the hop 

 gardens during some seasons, may be found 

 in the earlier part of the year, before the 

 bines make luxuriant growth, feeding upon the 

 sloe. 



Individually the Aphides would be compara- 

 tively harmless, for they are diminutive in size 

 and of comparatively frail structure ; but so 

 great and swift are their powers of multiplication 

 and development, that in an incredibly short 

 space of time thousands may be found crowding 

 the stems and leaves of plants which a week 

 previously harboured but a few specimens. 



