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 D)-. 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 ki a majority of the species of a given locality. 



The most striking structural variation commonly met 

 with w^as 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. 

 hier()f/li/phic(f var. cotifluens and in the Mexican specimens, 

 ^ t r ( p nndaf a Sina bifida; specimens ot 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. hieroghjpJiica and O.undata are striking exam- 



