596 
JOURAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
economic forms on a stable basis. Woodworth (1888-89) published a 
preliminary review of the genera but did not attempt to define the 
species. Gillette (1898) in his “American Leaf-Hoppers of the Sub¬ 
family Typhlocybinae” ignored fabae of Harris, the genus Chloroneura 
of Walsh, and did not place C. maligna or C. malifica , the two injurious 
species from apple which Walsh described under this genus. Hartzell 
(1924) in his “The Genus Empoasca in North America” followed Gillette 
in the use of color characters for the separation of species and also 
failed to recognize any of the earlier described injurious species. 
A careful study of some of the more common species of Empoasca 
has shown that many of them are widely variable in color characters, 
ranging all the way from uniform green or yellowish to definitely lined, 
spotted, banded, or highly ornamented forms. It is therefore probable 
that when the entire genus is carefully studied there will be other syno¬ 
nyms added to the lists below. These will not, however, affect the name 
of the species as in this study the older names have all been considered. 
In this connection it is well to remember that Harris, LeBaron, 
Walsh, and Forbes were only interested in discussing species sufficiently 
abundant to be injurious to crops. Walsh described other species be¬ 
cause as he states, “Of these six divisions, the four last all comprise 
species of about an eighth of an inch in length, and of a uniform pale 
green or yellowish color, with scarcely any markings. These I propose 
to describe, as they are liable to be confounded with the two foes of the 
apple and pear.” Naturally these must have been representatives of the 
more common and widely distributed species in the region. A detailed 
study of his species bears out this conclusion. 
The Rose Leafhopper ( Typhlocyba rosae Linn.) 
This species is white with a golden tinge and is considerably larger than 
fabae. The nymphs are white instead of green as in the two following 
species. It has two generations annually. The winter is passed as an egg 
under the bark, usually of a rose bush, the first generation nymphs then 
live on the underside of the rose leaves, their punctures whitening the 
upper surface. The adults fly to the apples and the second generation 
follows unicolor in whitening the older apple leaves and doing serious 
damage. This is in nature a rose pest and both generations may remain 
on that plant. On the other hand, in seasons of unusual abundance, the 
overwintering eggs may be laid on the apple. This is the common pest of 
apples in the northwestern states and is occasionally seriously injurious in 
