204. PHIL RAU AND NELLIE RAU 
10. In animals (similar to those considered in this paper), 
in which the female is fertilized once for all, is there any relation 
between time spent in copulo and the fertility of the eggs; i.e., 
does a long period of copulation insure the fertility of all the eggs? 
11. Is copulation itself correlated with longer or shorter life? 
12. The effects of climate. 
13. Food conditions of the adult; its effect upon the present 
and the subsequent generations. 
14. Nutrition and environment in developmental stages. 
These ideas, which make no claim of completeness, were gleaned 
principally from work with these insects, hence many are inade- 
quate or cannot apply to other forms. It is true that many organ- 
isms will not permit of such investigation, and that confinement 
in some cases will cause marked changes. It may be years before 
sufficient and conclusive data can be had for the solution of the 
problem, but the vital importance of the phenomena of longevity 
in relation to the interests of the human race, as well as biologically, 
should at once arouse investigators to. the accumulation of such 
data, even though it be only as by-products to their chosen line of 
work. 
St. Louis, Mo., October 30, 1911. 
