THE rSITIIYRUS VES TALIS. 



■^ij 



pellets crowded one over the other is observed, and tliese little 

 things form the paste which is destined to nourish the future 

 larvae. Mixed with them, and encircled with wax, there are either 

 eggs, larvae, or cocoons, and at certain times of the year cups of 

 wax, which contain a very pure honey, may be seen on the sides 

 of the nest. The larvae resemble those of other bees, and they 

 spin themselves cocoons, which are egg-shaped, and which are 

 usually found pressed one against the other. They are of different 

 dimensions — the smallest, always the most numerous, are the 

 cocoons of workers ; those of medium size belong to males ; and 

 the largest contain fertile females. Before getting out of the 

 cocoons they have to be cut round at one end so that a portion 

 comes off resembling a lid. 



In the accompanying engraving there are many workers of 

 this bee, and a large female is represented on the ground on the 

 right hand side. The cocoons are exposed to view. 



Another humble bee {Bombus terresiris) is a very large kind, 

 and forms its nests in the earth at a considerable depth. These 

 bees do not use mosses, but make a lining to tlie roof of their 

 dwelling with layers of wax. 



Formerly certain Hymenoptcra were classed by all naturalists 

 amongst the humble bees, and, indeed, a superficial examination 

 of them permitted this to be done, for they have the same shape, 

 size, and colours, and look like them ; but Lepeletier de Saint- 

 Fargeau recognised them as parasites, and collected them under 

 the genus Psithyms. These insects which are so like the humble 

 bees have only two kinds of individuals amongst them, for none of 

 them are workers. There are males and females, and these have, 

 as might be expected, no implements for working. Every species 

 of humble bee has its parasite, its particular Psithyms ; and 

 curiously enough the parasite has the peculiar colouring of the in- 

 sect it robs, and usually there is no difficulty in telling the habits 

 of a Psithyms by its shape and tints. There is something in this 

 resemblance more than chance, for it will be found that some flies, 

 not wasps or bees, but Diptera of the genus Volucclla, which are 

 parasites in the nests of humble bees and wasps, resemble their 

 unwilling hosts in their colours. One of the commonest species 

 of the genus Psithyms {Psithyms vcstalis) resembles the common 



