244 TRANSFORMATIONS OF INSECTS. 
lumps of mud which have been thrown against the walland be- 
come dried up. They are the constructions of this ymenoptera, 
and when they are examined closely they will be found to be as 
hard as Roman cement, and to be made up not with mud, but with 
a mixture of gravel and earth. The lumps are more or less arched, 
and it is very evident that their rounded state is not a matter of 
chance. This mixture of earth and gravel sticks to the wall with 
the greatest tenacity, and the chisel and hammer are requisite to 
detach it. Now, these ugly and dirty looking masses have been 
carefully built up, with a wonderful amount of art, by a single 
flymenoptera, which has been the architect and workman at the 
same time. The labours of the Chalicodoma begin in the month 
of May, and soon after it is born. The female explores and 
goes over a wall and chooses a particular spot, and having 
settled that essential point, she goes off to collect building 
materials, and if followed, will be noticed to alight upon a 
‘sandy and gravelly soil. The insect takes up little masses of 
sand and small stones, of a certain size, with its mandibles, then 
it disgorges a little saliva and sticks them to some grains of earth, 
and thus agglutinates the earth and the sand so as to form the 
mortar which it is going to use in building. When it has worked 
up a little piece it flies off with its burden, and returns to its 
wall to fix on this ‘first quantity of cement. The same trouble 
is taken over and over again, and then, the mass of mortar 
appearing sufficient to permit other building operations to be 
commenced, the bee sets to work to mix all the earth, and usually 
she labours so well as to complete a little cell in one day. This 
cell is open to a certain extent, and the bee enters it several 
times to make the inside walls smooth. Then something else 
besides building has to be done, for the cell has to be victualled, 
and the Chalicodoma flies off to collect honey and pollen from the 
flowers. It makes up a sweet cake from them, which will be the 
future nourishment of its larva, and then it stuffs the cell nearly 
full of this food, and lays an egg in the midst. The Hymenoptera 
walls up the cell and sets to work to construct another close to it, 
then a third, and sometimes as many as twelve or more. These 
cells are placed rather irregularly, and are not found to be of the 
same number in every nest. All the cells are built, filled with 
