166 
BRITISH BEES. 
those which collect it upon the whole limb, viz. the coxa, 
the femur, the tibia, and first joint of the tarsus, (the 
femoriferee) , and those which gather it merely upon the 
shank and basal joint of the foot (the cruriferce). These 
collectively form a well-defined group, and why Panur- 
gus should be separated from the brush-legged bees, 
when it is a most conspicuous instance of the faculty, 
even more so than any other of the Scopulipedes, I have 
yet to learn. It is true its mode of collecting closely 
resembles that practised by the Andrenidce, as does also 
the furniture for the purpose of its posterior legs, but 
being essentially collocated with the Apulce or normal 
bees by its tongue, it fittingly links itself to the other 
brush-legged Apidee (which have hitherto been placed be¬ 
tween the Dasygasiers and the Social Bees), by means of 
the genus Eucera, by reason of its two submarginal cells, 
the structure of its maxillary palpi, its mode of burrow¬ 
ing, and by each being infested by a similar parasite— 
a Nomada, which in accommodation to the size of the 
sitos is the largest of the genus. Nomada does not 
occur as a parasite upon any other of the brush-legged 
bees, or indeed upon any other of the true bees at all, 
which peculiarity brings these two genera into close 
contiguity to all non-parasitical Andrenidee , all of which 
have their legs furnished with polliniferous brushes, and 
upon which subfamily, exclusively of these two instances 
of Panurgus and Eucera , Nomada is solely parasitical. 
With respect to the two submarginal cells to the 
wings, nature must have some reason for the limitation, 
for we find it prevalent also throughout the Dasygasiers , 
or hairv-bellied bees. 
t/ 
The next very natural group is consistently central. 
It comprises the cuckoo-bees, which are naked-legged 
