THE VESriDM. 233 



progeny with sufficient nourishment. The larvce soon become 

 full-grown, and spin a silken cocoon, which fills up the little cell, 

 and thus enclosed they are transformed into nymphs, the meta- 

 morphosis into the adult form occurring shortly. The new wasps 

 thus produced are all workers, or rather workeresses, for they are 

 sterile females, and they are created to take the part of nurses to 

 a progeny which does not belong to them. These workers begin 

 their duties as soon as they become perfect, and from that 

 moment the mother of the nest, who has been so laborious, and 

 who was so industrious when all alone, begins to lead a quiet life, 

 and to do little or nothing, for she has plenty of nurses to take 

 care of the little ones. The workers increase the extent of the 

 nest, and prepare cells for the larvae, and, when this is done, the 

 mother completes another great batch of egg-laying, and deposits 

 an egg in each cell. The larvae which come from these eggs do 

 not turn into workers only, but into male insects and females 

 which are not sterile. It is not known, how many egg-layings 

 take place during the year, but they probably vary with the 

 species. Very often the combs of the nests are found to con- 

 tain larvse late in the season, and when cold weather suddenly 

 sets in. In this case the wasps appear to understand that the 

 fruits will soon be all gone, and that the means of subsistence 

 will be cut off; but, in order that the larvae shall not sufter from 

 prolonged starvation, these intelligent creatures kill them at once, 

 so that the nest which was a few days before full of life, activity, 

 and animation, becomes a dreary solitude. The wasps construct 

 their nests out of vegetable matters, such as woody fibres and dead 

 leaves, and they make a sort of paper from these substances. 

 They triturate their building materials between their mandibles, 

 moisten them with their saliva, and mould them into a homo- 

 "•eneous paste, admirably suited for the construction of the cells 

 and the walls of the nests. The nests are made upon different 

 plans, all of which appear to have a distinct reference to some 

 peculiar conformation of the insect. But, although there are many 

 minor differences, still, in the main, all wasps' nests resemble each 

 other. The essential and most important parts of the nests are 

 the cells of the comb, and they are always built upon the same 

 plan. In the commencement the cell is a kind of cylindrical cup, 



