5H 
Saw-flies, Gall-flies, Ichneumons, 
Fig. 7). They are as large as bumblebees and with their heavy thick 
body and black color look much like them; they have 
the body more flattened and less hairy, however, and the 
hind legs of the females are never provided with a 
“corbiculum,” or pollen-basket (a concave smooth 
place bounded on each side by a row of long stiff curv¬ 
ing hairs), but are covered by a stiff brush of short 
hairs. These giant bee-carpenters tunnel into solid 
wood for a foot or more, dividing the burrow into a 
series of cells by partitions made of small chips stuck 
together. They are common all over the country, 
“choosing in civilized regions fence-posts and boards.” 
Certain very large species make their nests in the 
great fallen sugar-pines and yellow pines of the Sier- 
ran forests and are among the most characteristic in¬ 
sects of the giant-tree forests. 
The long-tongued family Megachilidae includes a 
F IG 719^ Nest of num ber of common and interesting bees, most familiar, 
perhaps, being the mason-bees (Osmia), the potter-bees 
(Anth'dium), and the leaf-cutters (Megachile). The 
Osmias are metallic, black, blue, or green, and make 
their nests of clay and sand, moulded into cells, and 
built in already existing cavities in stone walls, old posts, tree-trunks, etc., 
or in tunnels bored by the bee in plant-stems and twigs. The various 
species of Anthidium are black and rufous, or rufous 
and yellow, with the abdomen always banded or spotted 
with yellow, white or rufous. The females normally 
construct globular cells rather like the earthen vases 
of Eumenes (Fig. 701), but made of the resinous exuda¬ 
tions of pine-trees and other plants, or dig burrows in 
the soil which they line with down stripped from 
pudescent or woolly-leafed plants. Both Osmia and 
Anthidium sometimes make their nests in deserted 
snail-shells! The leaf-cutting bees (Figs 719 and 720) 
are usually carpenters as well as tailors; that is, they first 
bore a tunnel in some plant-stem or in wood, and then Fl ?- 7 2 °^ Smgle cell 
cut out pieces of green leaves with which they line the ter b ee> Megachile 
tunnel and partition in such a way as to form a series anthracina. (After 
of thimble-shaped cells each partially filled with a paste enlarged ^ somewhat 
of pollen and nectar on which an egg is deposited. The 
pieces of leaf are fastened together with a gummy secretion from the mouth 
of the bee. Comstock has found leaf-cutter nests in a “crack between 
leaf-cutter bee, Me¬ 
gachile anthracina . 
(AfterSharp; some¬ 
what enlarged.) 
