METHOD OF DETERMINING GENERA. 
179 
of tlie posterior tibiae, tbe 
centre glabrous. 
Body densely hirsute, spurs to 
all the tibiae. Bombus (26). 
Body subpubescent, no spurs 
to the posterior tibiae . . . Apis (27). 
It will be desirable to add a few observations to the 
preceding table to facilitate its use, and because, as 
many of the characters upon which it is framed are ex¬ 
clusively those of the female, it is necessary to point out 
the differences of their males, that the sexes of the 
genera may be duly recognized and associated. 
It may be first noticed generally that the antennae, 
in the males, are not usually geniculated at the scape, 
which is nearly always the case in the opposite sex, and 
they are also, with rare exceptions, always longer than 
those of their females. In Collates, Prosopis, Dasypoda, 
Panurgus, Ceratina, Nomada, Melecta, Epeolas, Stelis , 
and Anthidium , the habit or colouring of the males is 
so similar to that of the females, that their genus may 
be thus at once determined, and, in fact, the brief cha¬ 
racters in the table will embrace them. 
The male Eucera can be distinguished from those of 
Anthophora and Saropoda , both by the differences in the 
number of the submarginal cells of the wing, and by the 
extreme length of its antennae, whence the genus derives 
its name. In Andrena and Cilissa , the males have 
usually lanceolate bodies. In the latter genus there 
will be no difficulty in associating the legitimate part¬ 
ners ; but in Andrena , although general habit will usually 
