38o 



TRANSFORMATIONS OF INSECTS. 



them. Now in the spring these eggs are hatched, but they do 

 not produce caterpillars or grubs, but imperfect Aphides, which 

 have no wings, and which are all females. So far as is known, 

 all the males die in the autumn, and the females also as soon 

 as they have laid their eggs, so that in the early spring there 

 are no other Aphides in the world except these imperfect females. 

 Now these, as everybody knows, are the mothers of millions and 

 millions of plant lice, which are exactly like them — that is to 

 say, imperfect because they are wingless. These children are pro- 

 duced time after time, each set giving birth to others, and sometimes 

 there are nine or ten successive generations. The last generation 



THE ROSE Aphis. 



of Aphides does not produce those like unto itself, but perfect 

 male and female individuals with wings. All the generations of 

 imperfect females are not born from eggs, but they are born 

 alive, and they may be traced with the microscope like little 

 buds within the old ones. Bonnet, Reaumur, Owen, Huxley, 

 Carus, Leydig, and Balbiani especially have studied these interest- 

 ing insects. As soon as they are hatched the imperfect females 

 begin to grow and increase in size, and they attain their full 

 dimensions in ten or twelve days ; and then these curious little inside 

 buds are born at the rate of three, four, or seven a day. When 

 they are born they are miniatures of their mother, and in ten 

 days thc)^ begin to produce others. The second generation does 



