SAC-BEARING LEPIDOPTERA. 27 



only amongst the Aphides, but also amongst some moths*. 

 Subsequently, however, the thought occurred to me, that by the 

 careful dissection of these questionable Solenobia-nurses, a much 

 greater anatomical difference ought to be exhibited between 

 them and the females of Solenobia than between the Aphis- 

 nurses which produce living young and the egg-laying female 

 Aphides f ; for it is well known that all female Lepidoptera 

 possess two sexual orifices, one behind the other, of which the 

 extreme or hindmost one serves for the deposition of the eggs, 

 whilst the second orifice, placed before this (anteriorly), has to 

 receive the male generative organ during the act of copulation. 

 If these moths which laid eggs capable of development were 

 nurses, I expected, on examining them carefully, to find neither 

 the second sexual orifice on the exterior, nor the copulative 

 pouch (bursa copulatrix) and seminal receptacle in the interior, 

 parts which I had previously found in all female Lepidoptera J. 

 I was, however, quite deceived in my expectations, for all those 

 Talceporia which had been at first regarded by me as nurses, 

 proved, without exception, to be perfectly developed female 

 moths ; they all possessed the double sexual orifice, the copulative 

 pouch, and seminal receptacle, arranged and developed in the 

 same way as in other female Lepidoptera. The copulative pouch 

 and seminal receptacle were always empty and unexpanded. 

 Moreover no difference was discoverable (as to number, form 

 and contents) between the ovaries of these supposed nurses and 

 the same organs in other female Lepidoptera ; in short, I con- 

 vinced myself in the most positive manner, that in this case we 

 had nothing to do with nurses, but with virgin females §. 



After this discovery, the name of Parthenogenesis, which the 

 English naturalist Owen applied to the alternation of genera- 

 tions, must be peculiarly the most suitable denomination for the 



* See my Bemerkungen uber Psychiden, in the Jahresbericht der Schhsis- 

 chen Gesellschaft fur vaterldndische Cultur uber das Jahr 1850, p. 84 ; re- 

 printed in the Entomol. Zeitung, 1851, p. 341, and in the Transactions of the 

 Entomological Society of London, vol. i. 1851, p. 234. 



t See Froriep's Neue Notizen, Bd. xii. loc. cit. supra. 



% See Muller's Archiv, 183/, p. 417- 



§ I have already called attention to this fact at the meeting of German 

 naturalists at Gotha, as appears from the short notice in the Tagblatt der 

 2Sten Versammlung deutscher Naturforscher und Aerzte, No. 3. p. 28. 



