238 TRANSFORMATIONS OF INSECTS. 
that isolated female wasps originate different nests, or colonies, in 
the spring-time. He has proved that these females were born in 
the previous summer, and that they lived in the virgin state until the 
autumn, when they were fertilised just before their sinking into the 
profound sleep of hybernation. He states that when the female 
thus fertilised awakens in the spring-time, she lays eggs which 
turn to females, but not to males. The progeny consists at first of 
small females, and not of workers or neuters, as stated above. 
Von Siebold has dissected many of them, and has found that 
they are not workers — that is to say, females whose reproductive 
organs are dwarfed and arrested in their growth— but that they 
are perfectly formed females, full of eggs. This progeny, con- 
sisting of virgin females full of eggs, assists the original mother, 
not in working, but in filling the cells, for the eggs they lay are 
fertile, although they have never been fecundated. The increase of 
the nest takes place rapidly, and the larvae, receiving abundance of 
nourishment, are transformed into wasps as large as the mother. 
Towards the end of June or the beginning of July the comb 
presents a large -surface, and is composed of a very great number 
of cells. At this period some male individuals may be remarked 
for the first time among the numerous large and small females. 
Their number soon increases considerably. The observations of 
these facts suggested to Von Siebold that there might exist in 
Polistes a division of physiological labour — in this sense, that the 
fecundated females of the preceding year produce only female 
eggs, whilst the virgins of the new generation produce male eggs 
parthenogenetically. Experiment has confirmed this hypothesis 
in the most striking manner. Von Siebold selected a certain 
number of nests in the spring, at a period when the mothers had 
already reared one or two assistants. He removed the mothers 
from the nests and dissected them, in order to ascertain the con- 
dition of their egg-bearing organs. He always found evidences of 
fertilisation which must have occurred the year before. At the 
same time he entirely emptied all the cells of those nests which 
contained eggs, or any small larvae, preserving only the larvae of 
large size. Notwithstanding the disappearance of the mothers, 
the little virgins continued to take care of the larvae which had 
been preserved, and consequently the colonies did not perish. He 
