50 THE FERTILISATION OF FLOWERS. [PART Il. 
be of greater service in honey-getting (1, Fig. 13). In a state of 
rest, the lower parts of the mouth are even more securely hidden, 
and the mandibles can move even more freely, in Sphecodes and 
many species of Halictus than in Prosopis, for the upper lip (br, 2, 
Fig. 12) folds down and completely covers the laminz and maxillary 
and labial palps. 
The three genera Sphecodes, Halictus, and Andrena have advanced 
farther from the state of the ancestral bees in regard to the develop- 
ment of their hairy coat than of their mouth-parts. Sphecodes has 
made the first step in advance; Halictus and Andrena have 
proceeded farther. 
Fria. 12.—Sphecodes. 
1.—-Right hindleg of S gibbus, L. 9., hind view. Lettering as in Fig. 10. 
2.—Head, with mandibles opened, but the lower mouth-parts folded and hidden by the labrum. © 
8.—Head, after removal of the mandibles and labrum, with unfolded and protruded mouth-parts. 
4.—End of labium, more highly magnified. 
Lettering of 2, 3, 4, asin Fig. 11. 
In Sphecodes the whole body is sparingly covered with hairs 
which show the first traces of feathery branching; the legs are 
more thickly clothed with hairs, especially the outer side of the 
tibize of the hindlegs (#, 1, Fig. 12); the tarsi (¢’, 1, Fig. 12) are 
about as narrow as in Prosopis, but the brushes on their inner side 
are a little better developed. The species of Sphecodes feed their 
young in a most primitive manner, viz. on the disgorged surplus of 
their own food; yet they certainly derive advantage from the 
hairy covering on their body and hindlegs, for the pollen which 
sticks there in their visits to flowers they wipe off with their tarsal 
brushes and use incidentally as food for themselves or their young. 
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