PARTHENOGENESIS AND ITS SEQUEL 301 



sporadically, apparently according to the abundance of 

 food. The winged form is sometimes so abundant as 

 to float about in swarms that darken the air. There are 

 at least three kinds of males — winged males, wingless 

 males with a functional mouth, and small wingless males 

 which have no mouth, and, one need hardly say, are 

 very short-lived. The Aphides are a feeble folk, indi- 

 vidually, but collectively a power in the land, causing at 

 times incalculable loss to the farmer and gardener ; but 

 on this head and on the subject of their strange habits, 

 and sometimes adventurous lives as slaves in the service 

 of Ants, no more than a hint may be dropped in these 

 pages. But some such aids to faith seem to be necessary 

 when those who are not tolerably familiar with these 

 insects are told of their amazing fertility. Linnaeus 

 long since estimated, in regard to one species, that in the 

 course of one year a single Aphis will give rise to a 

 quintillion of descendants — all produced without the 

 aid of a male. Every one of these females begins to 

 reproduce within from ten to twenty days of her birth, 

 but even this statement does not bring home the result 

 of such an astounding fecundity like Huxley's calculation 

 which was carefully worked out. He estimated that 

 the produce of a single female would, in the course of 

 ten generations, supposing all the individuals to survive — 

 and possess the normal fertility of their race — " contain 

 more ponderable substance than five hundred millions of 

 stout men: that is, more than the whole population of 

 China." 



To explain such a riot of reproduction one might 

 almost suppose these insects to be imbued with a dread 

 of the impending dissolution of their race, and endowed 

 with the power to avert such a calamity by these 



