October, ’24] 
ball: names for apple and potato leafhoppers 
595 
namely Typhlocyba rosae, Empoasca maligna and E. fabae. A key to the insects and 
another to the injury will assist in determination. The earliest species described by 
Harris and Walsh are for the first time considered and their scientific names applied. 
This should give a stable scientific nomenclature and if the common names recom¬ 
mended are adopted, confusion can be avoided in the future. 
There has been much confusion and uncertainty in regard to the 
number of species of leafhoppers infesting the apple as well as to the 
scientific and common names that should be applied. The fact that two 
of these species also seriously injure other economic plants has served to 
complicate the situation. Sufficient study has now been made of the 
subject in different parts of the United States to warrant a fairly defi¬ 
nite statement that three species of the Eupteryginae ( Typhlocybinae) 
and only three are commonly found on apple trees. Parrott (1909) 
was the first to point this out for New York conditions. Lathrop (1918) 
working at Geneva differentiated the nymphs and worked out the life 
histories. Later studies by Childs (1918), the writer (1918), Fenton 
and Hartzell, (1923) Ackerman, and others, have confirmed these re¬ 
sults for the different apple-growing regions of the United States. 
These three leafhoppers can be readily separated by the following key.— 
A. Nymphs white, adults white or pale golden; two generations of nymphs, the 
first one early. The Rose Leafhopper ( Typhlocyba rosae Linn.) 
AA. Nymphs and adults green. 
B. Adults stout, deep green, with a blunt head, a single generation of nymphs 
appearing early. The Apple Leafhopper ( Empoasca maligna Walsh) 
BB. Adults slender, fragile, pale green, with an angled head, two generations 
of nymphs, the first one appearing late. 
The Potato Leafhopper (Empoasca fabae Harr.) 
These leafhoppers may also be separated by the appearance of the in¬ 
jury they cause. 
A. White spotting on the upper surface of the older leaves, especially in the lower 
part of the crown of bearing trees, leaves remain flat, (nymphs found on under 
surface only, eggs winter in bark.) 
B. Nymphs and adults white; occur throughout the season on rose and apple. 
The Rose Leafhopper. 
BB. Nymphs and adults green, nymphs early only, adults later and confined 
to apple. The Apple Leafhopper. 
AA. Curling and distortion of young leaves of watersprouts, tips or nursery stock; 
tips and margins of badly affected leaves turn brown, no white spotting. On 
potato, apple, beans, raspberries, gladioli, etc. Adults hibernate and lay eggs 
through a long period. The Potato Leafhopper. 
No serious attempt has been made previous to this time to accurately 
determine or place the earlier described species of Empoasca and Typhlo¬ 
cyba of Harris and Walsh and thus place our nomenclature of these 
