116 
BRITISH BEES. 
pedes or naked-legged, from tlieir not having the neces¬ 
sary apparatus of hair upon the posterior thighs or shanks, 
for the conveyance of pollen wherewith to store their 
nests. Thus nature, having rendered them unable to 
perform this duty to their offspring, has imposed upon 
them the necessity of resorting to strangers to support 
them, and they are not led to it by idleness or indifference. 
These insects consist, with us, of six genera, the species 
of which are individually attached to some particular 
bee, who thus nurtures their young. They are, as a rule, 
gayer insects than those which they infest, and the genus 
most abundant in species is Nomada , which attaches 
itself chiefly to Andrena , although some of its species, 
especially the smaller ones, infest the species of Halic- 
lus, and one frequents Eucera. Melecta appears confined 
to Anthophora; Epeolus to Colletes ; Stelis perhaps to 
Osmia, judging from the great similarity of habit; and 
Ccelioxys to the constructive Megachile. None of these 
parasites resemble their sitos, but Nomada is exceed¬ 
ingly different, being in its gay array more like a wasp 
than a bee. The only close approach in the appearance 
of a parasite to the insect upon which it is parasitical is 
in the resemblance between Apathus and Bomhus, which 
are so alike that they were long continued to be united in 
the same genus, until the peculiar characteristic of the 
parasitical bees was detected, when they were readily se¬ 
parated. Although, cuckoo-bees as they are familiarly 
called, they could not be associated with the Nudipedes, 
because their posterior legs, though not pollen-conveying 
organs, are hairy; but the Cenobites, to which section 
they belong, have a peculiar and distinguishing structure 
of that limb. They are further separated from the Nudi¬ 
pedes by several frequenting the same nest, thus habi- 
