PARTHENOGENESIS. 21 



perceived by him. The other case which is also usually reckoned 

 as a proof of a Parthenogenesis, relates to the observations made 

 by Pallas* upon Psyche graminella and Fumea nitidella,to which 

 I shall hereafter pay a closer attention (p. 24). Those cases of 

 Lucina sine concubitu which are supposed to have been observed 

 in Bees and Gall-flies, are also passed over here, as I must sub- 

 sequently subject them to a separate criticism. 



If we glance once more over all the cases hitherto referred to, 

 which were supposed to give evidence of a Parthenogenesis, the 

 whole of them agree in that the soi-disant spontaneous evolution 

 of the brood w r as noticed accidentally and unexpectedly by the 

 observers, so that all those precautions which are necessary for 

 the attainment of a certain observation fulfilling all the require- 

 ments of science, were entirely neglected. For this reason, 

 therefore, we must doubt the correctness of the consequences 

 which the above-mentioned naturalists have derived from their 

 observations, and the more so, as we can directly oppose to these 

 observations, others which were made from the commencement 

 with the view of obtaining a certainty with regard to the possi- 

 bility of a spontaneous development of the unfertilized eggs of 

 insects, and which, with the employment of all the necessary 

 precautions, have only furnished negative results. As evidence 

 of this I may cite the multifarious observations of Reaumur, 

 Rosel, and the Theresians, who never obtained caterpillars from 

 the eggs laid by unimpregnated female moths. Direct experi- 

 ments in rearing caterpillars from the unimpregnated eggs of 

 moths have been made by Kefersteinfj according to his own 

 statements, in which however he always came to a negative re- 

 sult. But there is an observation made by Blancard and Aude- 

 bert upon Parthenogenesis in Spiders which may even be placed 

 in opposition to the above-mentioned inadmissible observations, 

 and this shows that the Spiders also are subjected to the general 

 physiological laws in their reproduction. Blackwall J, namely, 



* See Nova Ada Physico-medica Academiae Natura Curiosorum, torn. iii. 

 1767, p. 430: " Phalaenarum biga, quarum alterius Femina artubus prorsus 

 destituta, nuda atque vermiformis, alterius glabra quidem et impennis, attamen 

 pedata est, utriusque vero, sine habito cum masculis comraercio, foecunda ova 

 parit." t See Entomologische Zeitung, 1842, p. 90. 



J See Annals of Natural History, 1845, vol. xv. p. 227. 



