1880.] 129 



few hatched out more or less completely, and died. Two, however (of 

 the seven in one batch), were more fortunate. These came out on 

 July 29th, and for some hours seemed very feeble and barely alive. 

 Next morning I found that one, which subsequently took the lead of 

 its fellow in all respects, had crawled away under cover, and the other 



, was able to follow its example. I could not find that they had eaten 

 anything till the even of the 31st. After that, however, they throve 

 apace. The larger one passed its first and second moults on the 3rd 

 and 7th of August, the smaller following it on the 4th and 8th. The 



\ former pupated on the 14th, and the imago was excluded on the 

 19th. The latter, having pupated, August 15th — 16th, appeared to go 

 on well till the time for the exclusion of the beetle, when its further 

 development became arrested, and it died. The survivor was weakly 

 at first, and rather imperfect always as regards the elytra, which are 



: somewhat small, and do not close in the middle line. It has, however, 



| thriven well, and developed that enlargement of the abdomen peculiar 

 to the female. But up to the present (September 22nd) it has laid no 

 eggs, nor shown any inclination towards males placed in the pot with it. 

 When it became obvious that no more parthenogenetic eggs were 

 to be obtained from these beetles, I placed the survivors of them in 

 succession in a pot with a (the same) male beetle, with the result that 



imost afterwards laid fruitful eggs in the ordinary way. I mention 

 this because it seems to be in contradiction, as far as these insects are 

 concerned, with the statement of von Siebold (" Beitrage," p. 89): 



|'*Es ist nun eine bekannte Sache, dass, wenn Insecten-Weibchen vor 



Lder Begattung erst einmal Eier zu legen angefangen haben, ihre 

 Mannchen alsdann mit ihren verspateten Liebesbezeigungen bei ihnen 



Ilnichts mehr auszurichten im Stande sind." 

 If now I may be permitted to make a few general observations 

 Ion some of the points indicated for further inquiry, rather than 

 I established, by the foregoing experiments, I would say : (1) that 

 parthenogenesis seems to occur chiefly in the first-laid batches ; (2) 

 that it is peculiar to some females, while others appear to be exempt 

 I from it ; (3) that confinement and domestication, as it were, acting 

 i hereditarily, which we already know so profoundly to affect the 

 I generative system in the higher animals, appear to favour this mode 

 f }f reproduction in Gastropliysa raphani ; (4) that there are degrees 

 pf viability in parthenogenetic embryos, so that the development seems 

 1 to be arrested chiefly at certain points, as at the hatching of the egg 

 and the exclusion of the imago. In this respect the Gastropliysa egg 

 behaves very much as the ovum of Bombyx mori is reported to do (v. 



