666 THE STUDY OF INSECTS. 



of the genus Andrena (An-dre'na). Some of these nearly 

 or quite equal in size the workers of the honey-bee. They 

 build their nests in grassy fields, sinking a perpendicular 

 shaft with branches leading sidewise to the cells. The 

 main shaft sometimes extends to a depth of more than one 

 foot. These bees, though strictly solitary, each female 

 building her own nest, frequently build their nests near to- 

 gether, forming large villages. Sometimes a village, or we 

 might say a city, of this kind, covering only one square rod 

 of ground, will include several thousand nests. While 

 writing this account we have received from a correspondent 

 a description of a collection of nests of this kind which was 

 fifteen feet in diameter, and in the destruction of which 

 about two thousand bees were killed a terrible slaughter 

 of innocent creatures ! 



The smallest mining-bees, in fact the smallest of all our 

 bees, belong to the genus Halictus (Ha-lic'tus). These 

 measure from one one-hundredth to three one-hundredth's of 

 an inch in length. They usually burrow in the sides of cliffs, 

 and especially in sand-banks, which often look as if they 

 had been used as targets for practice with a shot-gun, so 

 thickly are they studded with burrows of these bees. A 

 remarkable feature in the habits of the bees of this genus is 

 that several females unite in making a burrow into a bank, 

 after which each female makes passages extending sidewise 

 from this main burrow or public corridor to her own cells. 

 While Andrena builds villages composed of individual 

 homes, Halictus makes cities composed of apartment- 

 houses. 



Family APID^E (A'pi-dae). 

 The Long-tongued Bees. 



In the Apidae we find that the lower lip has been highly 

 specialized for the procuring of nectar from deep flowers. 

 Here the glossa is slender and greatly elongate, being longer 



