HYMEN OP TER A. 
669 
to place their cells. We have found these cells in a crack 
between shingles on a roof, in the cavity of a large branch 
of sumach, beneath stones lying on the ground, and in 
Florida in the tubular leaves of a pitcher-plant. 
Some species of bees make nests similar to those of the 
leaf-cutter bees, except'that the cells are formed of pieces of 
petals of flowers. The petals of Pelargonium are often used 
for this purpose. 
The small Carpenter-bee, Ceratina diipla (Ce-rat'i-na 
du'pla).—The nests of this bee are built in dead twigs of 
sumach and in the hollows of brambles and other plants. 
They are more common than those of any other of our 
solitary bees that build in these situations. This is a dainty 
little bee, about a quarter of an inch long, and of a metallic 
blue color. She always selects a twig with a soft pith 
which she excavates with her mandibles, and so makes a 
long tunnel. Then she gathers pollen and puts it in the 
bottom of the nest, lays an egg on it, and then makes a par¬ 
tition out of pith-chips, which serves as a roof to this cell 
and a floor to the one above it. This process she repeats 
until the tunnel is nearly full, then she rests in the space 
above the last cell, and waits for her children to grow up. 
The lower one hatches first; and, after it has attained its 
growth, it tears down the partition above it, and then waits 
patiently for the one above to do the same. Finally, after 
the last one in the top cell has matured, the mother leads 
forth her full-fledged family in a flight into the sunshine. 
This is the only case known to the writer where a solitary 
bee watches her nest till her young mature. After the last 
of the brood has emerged from its cell, the substance of 
which the partitions were made, and which has been forced 
to the bottom of the nest by the young bees when making 
their escape, is cleaned out by the family, the old bee and 
the young ones all working together. Then the nest is used 
again by one of the bees. We have collected hundreds of 
these nests, and, by opening different nests at different sea- 
