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, Avhen 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 arc 

 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 

 PoUsics 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 Q^^'^ 

 parthenogcnetically. 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 larvse, 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 



