82 
BULLETIN OF WISCONSIN NATURAL HISTORY SOCIETY. VOL. 2. NO. 1. 
SUMMARY AND CONCLUSIONS. 
I. The form unit of Acris gryllus v. crepitans for Madi- 
son, Wisconsin, has been described. 
II. Quantitative determinations from one hundred individ- 
uals have been made of a number of characters and seriated. 
III. The variation of color of the back and of the number of 
tuberosities has been found to be verv- great. 
IV. The males are smaller than the females. 
PLACE-MODES. 
The determination of place-modes has for its object the investi- 
gation of evolution by exact quantitative methods. It results in 
fixing the conditions of a species in a particular locality at a 
particular time, thus giving a basis upon which to determine any 
change which that same species may undergo in the same locality 
after a definite lapse of time. The changes which a species may 
undergo in a relatively small number of years under ordinary 
conditions of environment are not sufficient to be detected in 
cases where descriptions are quaHtative only or based upon a 
few individuals, but where a large number of individuals, taken 
at random, are measured the modes may be used as standards for 
reference. 
Aided by such determinations, we can know the rate and di- 
rection of any change which a species may undergo, so that we 
may draw more definite conclusions concerning the causes of spe- 
cific change. The comparison of place-modes throughout the 
range of the species has yielded important results. To quote Dr. 
C. B. Davenport: ''The establisliments of these place-modes for 
various species in various localities is the first sure step towards 
the solution of the problem of the Origin of Species.'^ 
Work of this nature is suggested for those who desire to make 
actual contributions to our knowledge of botany or zoology^ and 
yet lack the facilities or knowledge necessary for original contri- 
butions to the structure or relations of species. 
The following classes seem especially favorable for study be- 
cause of size, variability, ease of collecting, and, in many cases, 
of the presence of serial structures, which may be counted^ — rep- 
tiles, batrachians, fishes, decapods and myriapods. In plants the 
flowers and leaves offer numerous opportunities. 
This work was undertaken in response to the appeal of 
Dr. C. B. Davenport for the quantitative study oi variable species 
for the purpose of throwing light on the origfin of species. I 
would call attention of the members of naturalists' field clubs to 
the articles by Dr. Davenport in the bibliography. This work is 
