parr u.] THE INSECTS WHICH VISIT FLOWERS. 47 
enormously, and at last formed the widely ramified family of bees ; 
the still extending branches of this family, our recent bees, show 
us in many ways gradations in their adaptations to a floral diet, 
which help us to recognise to some extent the lines of their 
evolution. | 
The species of Prosopis stand just on the same level with the 
primitive ancestral types of bees. In their almost hairless bodies, 
the narrow first tarsal joint, scantily provided with hairs (Fig. 10, ¢’), 
and their very slightly elongated mouth-parts, they completely 
resemble the Sand-wasps, and only claim to be admitted to the 
family of bees by their manner of feeding the young. They fill 
Fic. 10.—Right hindleg of Prosopis variegata, 9. Seen from. behind. 
ce, coxa ; tr, trochanter; /, femur ; ti, tibia; t, tarsus: @, first joint of tarsus. 
(The tibia and tarsus are drawn too hairy). 
their brood-chambers (which are lined with a hard cement’ by 
means of the broad tongue) with a mixture of disgorged honey 
and pollen, which serves as food for the larve on hatching. These 
little active insects, which themselves have a peculiar odour, prefer 
strongly scented flowers, Reseda, Ruta, Lepidium sativum, Matricaria, 
Achillea, ete., where they alternately suck honey and eat pollen. 
In spite of their smooth bodies, sticky pellen adheres frequently 
to them, especially to the parts of the mouth and to the slightly 
hairy legs; these have feebly developed brushes on their tarsi 
(Fig. 10, ¢’), by which the bee can clean the whole upper surface 
of its body after burrowing, but no other part of the body. has 
any development of hairs suited for collecting pollen. 
