The Ecoloyy of a Sheltered Clay Bank 245 
The parasites also love the sunlight. This point leads 
us at once into a maze of interrelations between sun- 
light, parasites and hosts. The very short life cycle of 
Anthophora abrupta eliminates from consideration prac- 
tically all of the Dipterous parasites, because by their 
early emergence they escape the parasites and their suc- 
ceeding generation is practically provided for before the 
most of the parasites are born. Hence Anthophora has 
to struggle against only the Chalcids, the cuckoo-bees 
and possibly one species of Diptera in order to main- 
tain her species. While these three parasites did evi- 
dently prey upon this Anthophora population to some 
extent, their success depended to a far greater extent 
upon the white-banded bees as hosts since the duration 
of the life of the latter was more than twice that of the 
Anthophora bees, and since the white-banded bees emerg- 
ing later in the summer were the possible hosts of more 
than three times as many species of parasites. It is 
little wonder then, that the species which was being 
rapidly exterminated left the sunshine and the enemies 
which swarmed in it, and sought the ill-lighted recesses 
of the bank. Of course, it is really a problem whether 
these bees actually left the sunshine and crept away, or 
whether the parasites had merely exterminated all those 
which persistently remained in the sunny areas. With 
nations of bees—as with nations of men—there is not 
place in the sun for all. The numerous and the mighty 
occupy the favored places, and any others that wish to 
live may occupy the remaining corners of the earth until 
such a time as the powerful wish to usurp the places in 
the shade also. Usually the only hope of the ultimate 
survival of such oppressed species depends upon their 
powers of adaptation. Thus run the histories of the sur- 
