80 HYMENOPTERA. 



Professor Siebold has combated the theory of Landois, 

 and maintains his own views of the parthenogenesis of the 

 males ; and refers to the results that have been obtained by 

 anatomical and microscopical investigations of the larvae of 

 insects in the process of development in the egg; he conse- 

 quently expresses the greatest doubt of the correctness of the 

 theory set up by Landois. 



In support of his own views, Siebold refers to the great 

 work of Herold on the development of the cabbage butterfly, 

 wherein it is shown, that germs of the undeveloped repro- 

 ductive organs of the sexes are distinctly visible; and this 

 discovery, he has shown, has been confirmed by Weisman 

 in his remarkable work on the embryology of insects. 



In addition to this, Dr. Siebold combats the opinion of 

 Landois, tliat abundant nourishment produces females, and 

 a scanty supply males, by quoting the authority of some of 

 the most experienced observers of bee life, who all agree, 

 that all larvae up to the sixth day receive the same kind of 

 nourishment; that which is called food paste, upon which 

 the queens are abundantly fed until they change to the pupa 

 state; whilst the larvae of workers and drones, after the 

 sixth day, receive a coarser kind of food, so that here we 

 see workers and drones receiving the same kind of 

 nourishment. 



Assuming that the law of development of the sexes is 

 applicable to the whole of the Insecta, in what way can we 

 apply the theory of Landois to the Lepidoptera ? — the 

 cabbage butterfly, for instance ; the quality, as well as the 

 quantity of the food, is the same, and all the larvae are equally 

 free to consume the same amount of food. The same is the 

 case in a very large number of Coleoptera ; we may instance 

 those tribes that feed upon wood, and also the necrophagous 

 beetles, as well as many others. 



