246 Trans. Acad. Sci. of St. Louis 
vival of the fittest, the one proving its fitness by re- 
maining in the sunshine thereby accelerating its devel- 
opment, but curtailing its life, and the other proving its 
strength by continuing its existence in spite of tre- 
mendous opposition. One man’s meat is another man’s 
poison; one bee’s sunshine is another bee’s death. 
We eagerly await further developments in this com- 
petition, but at present we cannot forgo the temptation 
to speculate upon it. Will the white-banded bees, thus 
hard pressed, be finally exterminated? If so, what will 
be the effect upon Anthophora in return? Perhaps by 
that time they will have become so strong that, like the 
oak and the ivy, they will be able to carry on prosper- 
ously the work of the mining-bees and also maintain the 
various parasites without seriously feeling the strain. 
But again, if this happens, what will become of those 
later parasites which depended upon the white-banded 
bees, etc., those which, in fact, have killed the goose that 
laid the golden eggs? They will be compelled either to 
change their mode of living in some way, to migrate and 
perhaps perish in the attempt, or to quit living. If, how- 
ever, the parasitic Diptera adhere to their tendency to 
confine themselves to sunny areas, and if at the same 
time the white-banded bees can adapt themselves to their 
dim corners where they have taken refuge, there is a pos 
sibility that the white-banded bees may again increase 
and at some time regain prestige. Of course, these last 
Sentences are merely speculative, and yet it is by pre 
cisely such cat and mouse methods as these that nature 
lets her many species run on in constant and deadly 
competition. 
