16 Annals Entomological Society of America [Vol. VIII, 
the professed ecologists, and that they are quite disposed to 
meet the latter gentlemen a very liberal halfway in the explora- 
tion and exploiting of their common territory. It is something 
of an obstacle, to be sure, to a codperative understanding of 
these two groups that they look in opposite directions, and thus 
approach each other backwards, the economic entomologists 
being interested primarily in conditions as they are and may 
be made to become, referring to the past only for clues useful 
in the solution of problems of the present and the future, while 
the pure ecologists are looking rather to the reconstruction of a 
vanished or vanishing past, and tracing ecological history as 
far back as their data will permit. Each of these two groups is 
performing, indeed, its most essential function; but it will cer- 
tainly be to the advantage of both that they should understand 
each other and should make the cross-connections necessary 
to enable each to apply the other’s products and to avail itself 
of the other’s services. 
It will help us perhaps to a clearer idea of just what kind of 
ecology is most needed in applied entomology if we see what, 
in general, the economic entomologists have lately been doing 
in the ecological field. A survey of reports and papers which 
have appeared in quite recent years will show us that, in ad- 
dition to the kinds of ecological data which have now become 
standard in discussions of economic species, there is a consider- 
able quantity of most interesting new work being done by en- 
tomologists on the effect of variations in temperature and mois- 
ture upon the metabolism, reproduction, and life history of 
insects—virtually an attempt to isolate the elements of weather 
and climate and to experiment with them separately as pre- 
liminary to experiment with the various combinations of them 
present in nature. These are the first steps in a very long road, 
with branches running in many directions. 
Pursuing one of these branches a few years ago I found 
myself on the boundary line of vegetable physiology, where I 
was fortunate enough to meet a botanical ecologist willing to go 
my way, and to him I was permitted to turn over the inquiry 
I was making, with a result, lately published in a doctor's 
dissertation at the University of Illinois, that the reason why 
I was sometimes driving injurious insects away from corn hills, 
with no injury to the seed or plants, by 4*preliminary treatment 
of the seed with repellant oils, but sometimes, on the other 
