234 THE WOODLANDS. 



thousandth part of a grain, and that it requires a man 

 to be very stout to weigh more than two million grains,, 

 he shows that the tenth brood of aphides alone, 

 without adding the products of all the generations 

 which precede the tenth, if all the members survive 

 the perils to which they are exposed, contains more 

 ponderable substance than five hundred millions of 

 stout men ; that is, more than the whole population 

 of China. Enormous as this calculation may seem, 

 it is clearly below the mark, for subsequent calcula- 

 tions, based on ascertained facts given in Buckton's 

 " Monograph of Aphides," throws the one above given 

 into the shade. 



If this reproductive power really exist, then it 

 will be asked, how is it that the world is not all 

 aphides ? This may be as readily accounted for in 

 the fact that the persistent destruction almost keeps 

 pace with their production. Ladybirds, both in their 

 larval and mature condition, devour myriads of plant- 

 lice. For this purpose they swarm around the hop- 

 gardens of Kent and Sussex. The larvae of these 

 little beetles are voracious enemies of the " Hop-fly " 

 and its kindred. This, however, is but one out of 

 many foes. Take, as an example, the aphis which 

 attacks wheat-ears, when in the pupa state it is 

 attacked by a small black fly called Ephedrus^ which 

 deposits an egg in its interior. This egg soon de- 

 velops a small maggot, which flourishes within, and 

 at the expense of the aphis. Later in the season 

 another small fly visits the wheat, and deposits its egg 

 within the already infected pupa. This egg in the 

 course of time is hatched, and now preys upon the 



