24 



TRUE PARTHENOGENESIS IN SOME SAC-BEARING 



LEPIDOPTERA. 



From the statements previously published I was unable to 

 convince myself, that the possibility of a true Parthenogenesis in 

 the insect-world was established beyond all doubt. In what 

 way the observations so constantly repeated of a Parthenogenesis 

 in the Psychidce were to be received and explained, I have shown 

 in a previous memoir in the Zeitschrift fur wisseaschaftliche 

 Zoologie*. A mistake is the more possible in this case, as the 

 excluded footless females of the genus Psyche copulate in the 

 interior of their former caterpillar-sac, and after the performance 

 of the copulation creep back again into the pupa- case, in order to 

 store it with fecundated eggs. A fertilized female Psyche of this 

 kind, which has retired completely into her pupa-case, has often 

 been regarded as an unexcluded virgin individual, whose power of 

 laying eggs capable of development could not but excite the 

 astonishment of those who were unacquainted with the mode of 

 life of the true Psychce, but could not in the least surprise any one 

 who was familiar with these mysteries. The Sac-bearers which 

 are separated from the true Psychides according to the modern 

 system and referred to the genus Fumea, may also give rise to 

 similar errors, as, although their females, which are furnished 

 with six legs, do certainly quit the former caterpillar-sac after 

 their exclusion, and await the males clinging firmly to the out- 

 side of the sac by means of their laying- tube, yet, after copula- 

 tion has taken place, they stuff the pupa-case, which remains in 

 the sac, so completely from top to bottom with eggs and wool 

 from the extremity of their abdomen, that the full pupa-case, the 

 cleft thorax of which is thus completely pressed together and 

 consequently appears to be closed, may very easily be confounded 

 with a still unexcluded pupa. 



After I had called attention to these important facts in the 



* Band 1. 1849, p. 93, " On the Reproduction of Psyche." 



