Miscellaneous. 299 



ovcnvhelincd with work, can only furnish her young with a scanty 

 supply of nourishment. These small individuals have hitherto been 

 regarded as workers or neuters; but tliis denomination is erroneous. 

 Von Siebold has dissected many of these small individuals of ralistes, 

 and ascertained, by the examination of their generative apparatus, 

 that they are not, like the worker bees, females ai'rested in their 

 development, but perfectly developed females the turgid ovaries of 

 which are filled with eggs ready to be laid. 



As soon as the origiu;d mothers have thus produced assistants in 

 the form of these active virgins, the increase of the nest takes place 

 rapidly, and the larva), receiving more abundant nourishment, are 

 transformed into wasps as large as their mother. Towards the end 

 i)f June or the beginning of July the comb presents a large sui-face 

 and is composed of a verj- great number of cells. At this period 

 sonu> male individuals may be remarked for the first time among the 

 numerous large and snitill females. Their number soon increases 

 considerably. The observation of these facts suggested to Von Siebold 

 tliat there might exist, in Polistes, a division of physiological labour — 

 in this sense, that the fecundated females of the preceding year pro- 

 duce oidy female eggs, whilst the virgixis of the new generation 

 ])roduce male eggs parthenogenetically. This hypothesis seemed to 

 find sujiport in the small number of ovarian tubes in FoUstes, which 

 can only produce an inconsiderable number of eggs. 



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 from these nests the mothers, and dissected them in 

 order to ascertain the condition of their generative organs. He 

 always found the ovarian tubes in full activity, and the seminal re- 

 ceptacle fidl of mobile spermatozoids. At the same time he entirely 

 emi)tied all the cells of these nests which contained eggs or any 

 small larvaj, preserving only the larva) of large size, N'otw^thstand- 

 ing the disappearance of the mothers, the little virgins continued to 

 take care of the larvoe which had been preserved, and consequently 

 the colonies did not perish. Von Siebold took the precaution to 

 mark, hi each of the nests experimented upon, the occupied and 

 empty cells. In a few days he perceived that some of the latter 

 contained eggs. Careful examination even enabled him to surprise 

 some of the little virgin wasps at the moment when they were 

 ovipositing at the bottom of a cell. These individuals were at once 

 sacrificed, when the sLx ovarian tubes were found to be completely 

 developed, filled with ova in different stages of growth, whilst the 

 seminal receptacle was perfectly formed but completely empty. 



Duiing this time, thanks to the assiduous care of the young virgins, 

 new fem;de indiWduals, produced from the large larva) which had 

 not been sacrificed, arrived at their complete development, and at once 

 took part in the labours of the society. The nests were consequently 

 eidarged by new ceUs, which were speedily occupied by eggs laid by 

 the virgins. AU these eggs (and this is the important fact) were 

 developed notwithstanding the absence of fecundation, and gave 



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