164 HONEY-DEW 



of their life upon a single spot on a single plant hardly 

 need the luxury of wings ; and so, in nine cases out of ten, 

 natural selection has dispensed with those needless encum- 

 brances. Even the legs are comparatively little wanted by 

 our modern aphides, which only require them to walk away 

 in a stately sleepy manner when rudely disturbed by man, 

 lady-birds, or other enemies ; and indeed the legs are now 

 very weak and feeble, and incapable of walking for more 

 than a short distance at a time under exceptional provoca- 

 tion. The eyes remain, it is true ; but only the big ones : 

 the little ocelli at the top of the head, found amongst so 

 many of their allies, are quite wanting in all the aphides. 

 In short, the plant-lice have degenerated into mere mouths 

 and sacks for sucking and storing food from the tissues of 

 plants, provided with large honey- tubes for getting rid of 

 the waste sugar. 



Now, the greater the amount of food any animal gets, 

 and the less the amount of expenditure it performs in 

 muscular action, the greater will be the surplus it has left 

 over for the purposes of reproduction. Eggs or young, in 

 fact, represent the amount thus left over after all the wants 

 of the body have been provided for. But in the rose-aphis 

 the wants of the body, when once the insect has reached 

 its full growth, are absolutely nothing ; and it therefore 

 then begins to bud out new generations in rapid succession 

 as fast as ever it can produce them. This is strictly 

 analogous to what we see every day taking place in all the 

 plants around us. New leaves are produced one after 

 another, as fast as material can be supplied for their nutrition, 

 and each of these new leaves is known to be a separate 

 individual, just as much as the individual aphis. At last, 

 however, a time comes when the reproductive power of the 

 plant begins to fail, and then it produces flowers, that is to 

 say stamens (male) and pistils (female), whose union results 



