IOWA ACADEMY OF SCIENCES. 
37 
by symbols or letters, as is often done, especially as in the 
majority of cases these varieties have already received 
names. 
In the prosecution of this work, I have had for study the 
collection of the Iowa State College and the Van Duzee 
collection, both very rich in material, through the kind- 
ness of Prof. H. E. Summers; the National Museum col- 
lection, through the kindness of Dr. L. 0. Howard; the 
Ohio State University collection and the private collection 
of Prof. Herbert Osborn; a series of Florida forms from 
Prof. H. A. Gossard; and a fine series of Eastern forms 
from Mr. Otto Heidemann; the Colorado Agricultural 
College collection; some typical specimens of Woodworth’s 
species, from the Illinois Laboratory, through Prof. Hart; 
and numerous smaller series sent in for determination. 
My own collection includes all but one of the forms enu- 
merated in the paper, as well as a large number of species 
from Mexico, the West Indies and South America, some 
two hundred species in all. 
This large amount of material has made it possible to 
more thoroughly investigate and define the ordinary vari- 
ations of a species and to recognize some hitherto very 
puzzling forms as only extreme variations in a specific 
type. Some of these variations were found to run through 
a considerable number of species, disrtibuted through sev- 
eral genera, often the same variation would be found to 
occur in a majority of the species of a given locality. 
The most striking structural variation commonly met 
with was the broadening of the head and consequent rela- 
tive shortening of the vertex noticed in the specimens 
from the Pacific Coast and Mexican points. This was 
particularly noticeable in the Western specimens of T. 
hieroglyphica var. confluens and in the Mexican specimens, 
tripunctata and bifida ; specimens of bifida from the West In- 
dies were intermediate in this character. Another common 
variation was the change in the ground color in pronotum 
and elytra from red to blue and even green, with all possible 
combinations and variations in these colors. The varia- 
tions in T. hieroglyphica and 0. undata are striking exam- 
