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-tenth to three one-tenths of an 
inch in length. They usually burrow in the sides of cliff’s, 
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 A?idrena 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 
