THE INIMICAL LEAFHOPPER. 75 
in the nymphal stages, ranging from those recently hatched to 
mature, but a few adults also were secured. 
Its particular habitat is throughout the country where bluegrass 
is the common pasture grass, and this is, perhaps, its favorite food 
plant. So generally distributed is it that it is almost impossible 
to sweep over any patch of bluegrass anywhere from Maine to Wash- 
ington without ‘finding representatives of this species among the 
leafhoppers that are captured. Throughout most of this territory 
it is usually the most abundant of the species taken, and in many 
cases it far exceeds all other species in numbers. In the statement 
of relative abundance, written by Mr. V. L. Wildermuth in another 
Yj 
Fia@. 13.—Map showing distribution of Deltocephalus inimicus. (Original.) 
place (pp. 14-15), it will be observed that this species may comprise 
about nine-tenths of the numbers captured. While bluegrass and 
timothy are the more common food plants, the species has a wide 
range and has been observed on wheat, oats, corn, millet, rye, clover, 
alfalfa, and a considerable number of wild grasses of the plains region. 
This general occurrence on different food plants makes it possible for 
the species to survive in almost any locality, and it is thus given 
abundant opportunities to migrate to any favorable crop which may 
grow within a reasonable range. 
LIFE HISTORY. 
(Figs. 11, 12.) 
Although the larva was mentioned by Say in his original descrip- 
tion, no study of the life history seems to have been made until 1892. 
General descriptions of the different stages are given in Pulletin 
No. 30 of the Bureau of Entomology and in Bulletin No. 20 of the 
