PARTHENOGENESIS. 23 



case, if the windows had been imperfectly closed, might a copu- 

 lation of the female Psychce have been possible and yet have 

 remained unobserved ! What unexpected errors one may be 

 exposed to in such observations, is also shown by a communica- 

 tion made by Lucas*, according to which a male and female 

 moth were evolved from t\vo pupae of the silkworm enclosed in a 

 common cocoon. It might be possible, if perchance both the 

 moths in such a common cocoon quitted their pupa-cases simul- 

 taneously, that they might have copulated in the interior of the 

 cocoon notwithstanding the narrow space ; and if then the female 

 alone had quitted the cocoon and laid eggs capable of develop- 

 ment, how easily might the still-concealed male have been over- 

 looked, and the case itself regarded as one of reproduction sine 

 concubitu \ 



* See Annales de la Societe Entomologique de France, torn. iii. 1845, p. Ixxxii. 



