1880 .] 
129 
few hatched out more or less completely, and died. Two, however (of 
the seven in one hatch), 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 r 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 81st. 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 showm 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 
most 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, w r ith the statement of von Siebold (“ Beitrage,” p. 89) : 
‘‘ Es ist nun eine bekannte Sache, dass, wenn Insecten-Weibchen vor 
der Begattung erst einmal Eier zu legen angefangen haben, ihre 
Mannchen alsdann mit ihren verspateten Liebesbezeigungen bei ihnen 
nichts mehr auszuriehten im Stande sind.” 
If now I may be permitted to make a few general observations 
on some of the points indicated for further inquiry, rather than 
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 
from it ; (3) that confinement and domestication, as it were, acting 
hereditarily, which we already know so profoundly to affect the 
generative system in the higher animals, appear to favour this mode 
of reproduction in Gctstrophysa raphani ; (4) that there are degrees 
of viability in parthenogenetic embryos, so that the development seems 
to be arrested chiefly at certain points, as at the hatching of the egg 
and the exclusion of the imago. In this respect the GnstropJiysa egg 
behaves very much as the ovum of Bombyx mori is reported to do (v. 
