242 TRANSFORMATIONS OF INSECTS. 



are either permanent or only last a year. The solitary species 

 lead a life like that of the fossorial Hyuicnoptcra ; and a single 

 female constructs a nest, makes the cells for its larvae, and 

 victuals them. The social bees have three kinds of individuals — 

 namely, males, fertile females, and neuters, which are also called 

 workers or sterile females. In those colonies which only last a 

 year some solitary female lays the foundation of the hive, and the 

 workers are gradually born and increase in number; but the 

 fertile females which are found in permanent colonies never do 

 any work, and, indeed, they are incapable of it, for the neces- 

 sary structures are wanting in them. There are certain species 

 amongst the bees — whose habits are like those of some insects 

 which have already been noticed in treating of the SphegidcE — 

 which have the instinct to enter the nests of industrious kinds, 

 and to deposit their eggs in the cells that have been partly filled 

 with food intended for the larvse. 



The bees we shall first notice differ from all others by not having 

 their hind legs made to collect pollen, and the genus Osviia con- 

 tains the most important of them. These Hyvienoptera build very 

 elaborate structures, and take almost a fantastic care about the dif- 

 ferent materials which they use for their cells, each species choosing 

 particular substances. They collect pollen, like other nest-making 

 Hyuicnoptcra, and make a cake of it for their larvae, but their legs 

 do not assist them in collecting it. But there are some stiff and 

 crowded hairs which cover the lower part of the abdomen of 

 these bees, and they answer the purpose of pollen collectors just 

 as well as the hind legs of the other bees. The Osmia rubs itself 

 against the stamens of flowers, and detaches the pollen, then it 

 collects some grains against the hairy structure, which retains 

 them, and then the insect returns to its nest carrying a greater 

 or less quantity of this important food. Of course the first care 

 of the bee .should be to get rid of its burden, but it does not 

 appear, at first sight, how this sticky pollen is to be moved 

 from off the hairs ; but a structure is at hand by Avhich this diffi- 

 culty can be overcome at once, for the Osniia is provided with a 

 kind of brush, which is placed under the first joint of the hind 

 legs, and as these extremities can* be moved in all directioi?s, 

 every morsel of pollen is speedily detached from the whole body. 



