BEES 



297 



compared with the beautiful comb of the honeybee, with 

 its symmetrical six-sided cells. In the great group of 



From Brehm's "Ttiierleben" 



FIG. 107. A leaf-cutting bee (Megachilc) : a, female; b, male; c, a rose leaf with 

 parts removed by the bee ; d , a nest in a cavity in a plant stem ; f-i, details of the 

 construction of the cells of a nest ; k, a pupa. 



bees we find still preserved representatives of numerous 

 stages of evolution, from the simple tunnel of the soli- 

 tary bee, to the complicated nest, with no less com- 

 plicated habits, of the most completely socialized kinds. 

 The true honeybees (Apis} are confined to the Old 

 World, except where they have been introduced by 

 man. In the tropics of both hemispheres, however, 

 are numerous species of stingless social bees (Tngona 

 and Melipona), mostly of small size. Some of these, 

 as if to make up for the absence of stings, have the 

 power of emitting an irritating liquid, and are ex- 

 tremely pugnacious when disturbed. 



4. Just as we find a series of types of nests, so also Mouth 

 do we find in the mouth parts of bees a beautifully " 

 graduated series leading from the wasplike type to 



