92 



TRUE PARTHENOGENESIS IN THE SILK-WORM MOTH. 



Having proved the occurrence of a true Parthenogenesis, com- 

 bined with such extremely remarkable phenomena, in the Bees, 

 I return once more to the Lepidoptera, in order to refer to the 

 Bombyx Mori, regarding which notices were constantly coming 

 to my ears, sometimes here, sometimes there, which indicated 

 the Silk-worm Moth as one which sometimes laid eggs capable 

 of development sine concubitu. The older statements relating 

 to this appeared to me at first to be equally unfounded with 

 the other cases of Parthenogenesis in the moths elucidated by 

 me (p. 12). 



How little inclination there was even formerly to believe in 

 any such Parthenogenesis of the Silk- worm, appears from a letter 

 written by Constans de Castellet, General Inspector of the Silk 

 establishments in the kingdom of Sardinia, in which* he reports 

 that eleven female silk-worm moths which had just crept out of 

 the cocoon were observed by him, which, in their virgin state, 

 deposited eggs, from which caterpillars and cocoons were 

 reared. Castellet, who had not expected this, and wished to be 

 sure that he had not deceived himself, repeated the experiment, 

 imprisoned the female cocoons in different rooms, and convinced 

 himself of the thriving of the silk-worms which he afterwards 

 obtained from the virgin brood deposited by these moths. He 

 made a report upon this case to Reaumur, who however an- 

 swered him shortly : ex nihilo nihil fit, and doubted the cor- 

 rectness of the facts. By such an answer from so distinguished 

 a naturalist, Castellet found himself induced to investigate the 

 affair closely once more, and believed that he had at last got at 

 the reason of it, by thinking that he saw that silk-worms in his 

 breeding-place, which were already very near the time for spin- 

 ning themselves up, had copulated. He thought he observed, 



* See the letter referred to : Sulle uova de* vermi da seta fecondate senza 

 V accoppiamento delle farfalle, in the Opuscoli Scelti sidle scienze et sidle arti, 

 torn, xviii. 17^5, p. 242. 



