52 UTILIZATION OF MINUTE LIFE. 



forth young. He immediately placed tlie latter in 

 confinement, and observed them give birth to other 

 young aphides. By following up the experiments 

 he saw produced before his eyes nine generations 

 of aphides, successively born without the concourse 

 of the two sexes. But it had been certainly ascer- 

 tained that there exist male and female aphides, and 

 it was also given to Bonnet to observe their accou- 

 plement. In autumn he saw the little winged aphides 

 couple with the females, which are much larger, 

 after which he saw no more young aphides appear : 

 the females laid eggs, which both Bonnet and Reau- 

 mur looked upon as averted foeti, as they never 

 seemed to hatch. Lyonnet was more fortunate : he 

 observed the hatching of eggs laid by the aphis of 

 the oak-tree. Dutrochet, in a short paper read in 

 1818, at the Paris Academy of Sciences, shows the 

 complete organization of the generative organs of the 

 male and female aphides, and has come to the con- 

 clusion that these insects are not hermaphrodite, as 

 Reaumur supposed, but that the opinion professed 

 by Trembley, that the fecundation which takes place 

 in autumn is sufficient to render fertile the nine 

 successive generations of females, appears most 

 probable.* 



The marvellous tinctorial properties of the cochi- 



* Dutrochet's paper was subsequently published in 1833 

 (' Ann. des Sciences Naturelles," vol. xxx.) 



