IN THE SILK-WORM MOTH. 99 



but still a month or two later than these. Unfortunately I had 

 not the satisfaction of obtaining caterpillars from the unfertilized 

 eggs which had become slate-grey and remained tense, and 

 which I had preserved with care through the winter, for they 

 also shrivelled and dried up entirely, when the next spring had 

 arrived. The same thing happened to me with a great number 

 of slate- grey and tense eggs, possessing exactly the appearance 

 of fecundated eggs, which were handed over to me by Herr 

 Steiner with the assurance that they were laid by virgin silk- 

 worm moths. After several months I found these eggs entirely 

 shrivelled, without my obtaining a single larva from them. 



In the year 1854, Herr Schmid of Eichstadt, who has occu- 

 pied himself for eighteen years with the breeding of silk- worms, 

 sent me a quantity of bluish-grey, tense silk-worm eggs, which, 

 according to his assurance, were derived from virgin moths. 

 From all these eggs caterpillars were actually developed. It 

 was of much consequence to me to rear the moths from these 

 caterpillars, in order to see whether only a single sex, either only 

 males or only females, would make their appearance from all 

 these unfertilized eggs which had arrived at development, as in 

 the case of the Psychidae and that of the Bees. 



Although I could state no definite motive by which I might 

 have been induced to expect beforehand the evolution of male 

 moths from the unfertilized eggs of the Silk-worm moth, I must 

 admit that, although without any definite ground, I cherished 

 the expectation that those silk-worms evolved from unfertilized 

 eggs would furnish nothing but male moths. For my justifica- 

 tion, I might certainly cite that remarkable notice of Carlier's 

 already mentioned (p. 20), which Lacordaire has communicated 

 in the following words* : "Get observateur a obtenu, sans ac- 

 couplement, trois generations du Liparis dispar, dont la derniere 

 ne donna que des males, ce qui mit naturellement fin a Pexpe- 

 rience." Although, as already remarked, this short notice con- 

 tains no proof that the observation therein communicated was 

 made with the necessary care and exactitude, it now acquires a 

 peculiar importance, since Dzierzon's theory has proved to be 

 correct. Even in the year 1852, 1 urged upon Dzierzon himself 



* See Lacordaire, Introduction, &c. torn. ii. p. 383. 



H 2 



