July 10, 1914 
11 C> C)'^ 
Vol. XXVII, pp. 125-136 
PROCEEDINGS 
OF TIIK 
BIOLOGICAL SOCIETY OF WASHINGTON 
KEY TO ^ITIE NEARCTIC GENERA AND SPECIES OF 
GEOCORIN^. 
(Hetehoptera ; Lygaeid^e.) 
BY W. L. .^IcATEE. 
U. S. Biological Survey. 
This paper is liased largely on material contained in the U. S. 
National Museum, for the privilege of using which the writer 
is indebted to Messrs. J. C. Crawford and Otto Heidemann. 
Mr. W. D. Pierce also kindl}’- submitted for examination the 
specimens collected by the staff of the Southern Crop Insects 
Investigation. 
The key includes 9 species and 8 varieties, and the paper 
makes some reference to every form known to have been 
described from the Nearctic realm except Geocoris duzeei Mon- 
tandon. 
The earlier descriptions of species of Geocorinai, like those of 
many other groups, often are de.scriptions of single specimens. 
As a rule, one may also say, color characters only are men¬ 
tioned. It remains therefore for subsequent writers to fix the 
description upon some form, and to point out structural char¬ 
acters sufficient to properly distinguish the species. 
Color is not only extremely variable, l)ut in the Hemiptera at 
least depends very much on age of the individual. In using 
color characters it must also he remembered that albinistic or 
melanistic forms of any of the species may occur, and that the 
structural characters variable as they also are must be allowed 
to decide the identification. In the species of Geocorina3 repre¬ 
sented in the United States, the color pattern of the undersurface 
is remarkably uniform. This is not to say that there may not 
be considerable variation in the details, but any of the species 
(12o) 
30— Proc. Biol. Soc. Wash.. Vol. XXVII, 1914. 
