MISCELLANEA. 345 



pas de bien determiner la nature mineralooique — il me parait etre de roche phitoniqne; 

 ce caillou de la forme et de la grosseur dun petit ceuf de poule, ou mieux encore de 

 la forme d'un ceuf de Palmipede, avait du servir, suivant M. Mantell, a faire cuire 

 Ics oiseaux. 



" 2*. Un grand eclat de silex noiratre, offiant sur I'une de ses faces presqiie 

 plane, le renflement en cassure conchoidale si characteristique des eclats de silex ob- 

 tenus artificiellement; I'autre face presente deux plans obliques separes par une 

 arete mediane et longitudinale: Tun des bords est plus tranchant que I'autre. 

 Suivant JNI. Mantell ce silex taille a du servir a couper les chairs. 



" 3". Plusieurs eclats d'obsidienne a, bords plus ou moins tranchants mais sans 

 forme definable. M. Mantell n'a donne d'autre renseignement sui- ces eclats 

 d'obsidienne que leur provenance de Rangataque. 



" 4". Un autre fragment de gres lustre a plans de cassure multiples et une seule 

 facette lisse, simplement indique comme pi-oveuaut de Ruamoa." 



These additional facts will, I think, be read with interest, and fully 

 justify the conclusion,* that in all probability the " Moa was ex- 

 " terminated, like the Irish gigantic Deer and the Dodo, by the 

 *' agency of man." 



Parthenogenesis in the Silk-worm Moth. 



In the Philosophical Transactions for 1856 I have endeavoured to 

 record all the species of Articulata in which virgin females have 

 produced fertile eggs. Among the Lepidoptera the genera Psyche 

 and Solenohia multiply generally by Parthenogenesis, while in other 

 genera this only occvu's as a rare and exceptional phenomenon. 

 While, however, some cases seem to be satisfactorily established, we 

 have no observations on the conditions of their occurrence. In the 

 Comptes E,endus for the 16th December, M. Jourdan records the 

 results of some experiments on the silk-worm moth. There is a 

 tradition among some of the ancient families of silk-growers in the 

 south of Prance, that one of the best ways of regenerating their 

 races of silk-worms was to employ what is called " virgin seed," that 

 is to say, unimpregnated eggs. 



To test the truth of this statement M. Jourdan made the 

 following experiments. He isolated 300 cocoons of a variety which 

 has four moults, and only gives one yearly silk crop ; and from these 

 he obtained 147 female moths and 151 males. Out of these 147 

 females only six laid fertile eggs — two gave 7, two 4, one 5, and one 

 2. These 29 eggs were the only ones which were hatched, though 

 many others passed through the early stages of embryonic develop- 

 ment. The whole number of eggs laid was about 58,000, so that the 

 proportion of fertile ones was about one in two thousand. 



He made a second experiment on a variety which, instead of one 

 generation in a year, has five or six, and undergoes three moults. 

 Out of 50 cocoons he bred 23 females and 26 males. Seventeen out 



• Rupert Jones, in Mantell's Wonders of Geology, 7th edition, p. 129. 



