1899] FLOWERS AND INSECTS 39 
and dry that it is apt to be blown away as soon as it is liberated 
from the anthers. The first step in the development of entomo- 
philous flowers was the secretion of nectar somewhere about the 
stamens and pistils, correlated with the modification of the flower 
so as to afford convenient resting places for insects, and the 
pollen becoming more adhesive, so that it would remain on the 
anthers after dehiscense and become attached finally to the 
bodies of the guests. The object of insect visits being the 
nectar, modifications favoring cross-pollination resulted in the 
various forms of diclinism and dichogamy. The perfection of 
nectar-bearing flowers naturally reached a high grade in the less 
specialized groups of plants, as, for example, the orchids, and 
was most frequently associated with the less specialized antho- 
philous insects. 
Along with the development of convenient landing places 
and sticky pollen, there has no doubt been an increasing number 
of insects which resorted to flowers for pollen. Finally, the 
most highly specialized of anthophilous insects, the Hymenop- 
tera, gave rise to a still more highly specialized group of insects 
which adopted the habit of provisioning their nests with nectar 
and pollen. Along with the acquisition of this habit the bees 
developed a coat of feathery hairs to which the pollen might 
cling, these hairs on certain parts of their bodies, as the hind 
legs and ventral surface of the abdomen, being greatly modified 
to form special pollen-carrying apparatus called scope. Thus 
the pollen became absolutely essential in the economy of the 
most highly specialized anthophilous insects. To the flowers, 
on the other hand, the bees became the most important visitors, 
because they had to resort to flowers more frequently than other 
Msects, and because they were provided with a coat specially 
fitted to retain the pollen, and at the same time exerted them- 
selves to get the coat as full of pollen as possible. 
That the development of entomophilous flowers with sticky 
pollen preceded the development of the bees is indicated by the 
fact that the less specialized bees only collect adhesive pollen. 
The most highly specialized bees, however, have acquired the 
