206 
BRITISH BEES. 
and it proceeds to the elaboration of another receptacle 
for a fresh brood until its stock of eggs becomes ex¬ 
hausted. Some species have two broods hatched in the 
year, especially the earlier ones,—for several present 
themselves with the earliest flowers,—but others are re¬ 
stricted to but one. The quantity of pollen they col¬ 
lect is considerable, and in fact they are supplied with 
an apparatus additional to what is furnished to any of 
the other genera in a curled rather long lock of hair 
that emanates from the posterior trochanters. This, with 
the fringes that edge the lower portion and sides of the 
metathorax, as well as the usual apparatus upon the 
posterior legs, enables the insect to carry in each flight 
home a comparatively large quantity of pollen, but per¬ 
haps scarcely enough at once for the nurture of one 
young one, and it therefore repeats the same operation 
until sufficient is accumulated. 
The exact period occupied by their transformations is 
not strictly known; it will, of course, vary in the spe¬ 
cies, as also in those in which two broods succeed each 
other in the year, but the larva rapidly consumes its 
store and then undergoes its transformation. It does 
not spin a cocoon, but in its pupa state it is covered 
all over with a thin pellicle, which adheres closely to 
all the distinct parts of the body. It is not known how 
this is formed; perhaps it is a membrane which trans¬ 
udes in a secretion through the skin of the larva, or it 
may be this itself converted to its new 7 use, which seems 
to be for the protection of all the parts of the now 
transmuting imago, until these in due course shall have 
acquired their proper consistency. 
These insects in their perfect state vary very consi¬ 
derably in size, both individually and specifically, the 
