THE HOME OF THE BEES. 371 
in eating out her cells, for our active little carpenter is 
provided with strong cutting jaws, moved by powerful 
muscles, and on her legs are stiff brushes of hair for 
cleaning out the tunnel as she descends into the heart 
of the solid wood. She must throw out the chips she 
bites off from the sides of the burrow with her hind legs, 
passing the load of chips backwards out of the cell with 
her fore-limbs, which she uses as hands. 
The partitions are built most elaborately of a single 
flattened band of chips, which is rolled up into a coil four 
layers deep. One side, forming the bottom of the cell, 
is concave, being beaten down and smoothed off by the 
bee. The other side of the partition, forming the top 
of the cell, is flat and rough. 
At the time of opening the burrow, July 8th, the cells 
contained nearly full-grown larvæ, with some half devel- 
oped. They were feeding on the masses of pollen, which 
were large as a thick kidney-bean, and occupied nearly 
half the cell. The larve (Plate 10, Fig. 4) resemble 
those of the Humble-bee, but are slenderer, tapering 
more rapidly towards each end of the body. 
The habits and structure of the little green Ceratina 
ally it closely with Xylocopa. This pretty bee, named 
by Say Ceratina dupla, tannels out the stems of the 
elder or blackberry, syringa, or any other pithy shrub, 
excavating them often to a depth of six or seven inches, 
and even, according to Mr. Haldeman (Harris MS.), 
bores in acorns. She makes the walls just wide enough 
to admit her body, and of a depth capable of holding three 
or four, often five or six cells (Plate 10, Fig. 11). The 
finely built cells, with their delicate silken walls, are 
cylindrical and nearly square at each end, though the free 
end of the last cell is rounded off. They are four and a 
