10 
BULLETIN" 19, U. S. DEPARTMENT OF AGRICULTURE. 
work a great amount of injury has not been observed. The other 
species most commonly found associated with T. comes is T. tricincta 
Fitch (fig. 6,b). This species, when present, is more likely to be found 
on the foliage of Delaware, Catawba, Brighton, and some of the wild 
species of grapevine growing along ravines or in woodlands. It 
is readily distinguished from comes by the larger size and by the 
fact that it has three broad black bars situated as follows: One 
just back of the head, another about midway across the elytra, and 
Fig. 6. — The two species of grape leafhopper most common in vineyards of the Great Lakes Region: 
* a, Typhlocyba comes; b, Typhlocyba tricincta. Greatly enlarged. (Original.) 
the third at the tips of the elytra. Nymphs of tricincta (fig. 7) 
have two black spots back of the eyes and two on the thorax. 
While making trips through the vineyard areas along the shore of 
Lake Erie as far west as Sandusky, Ohio, it was observed that in the 
Ohio vineyards east of Cleveland Typhlocyba tricincta was present in 
greater numbers than in the vineyards of Chautauqua County, N. Y., 
and of Erie County, Pa., although more than 80 per cent were still 
Typhlocyba comes. In the vineyards west of Cleveland T. tricincta 
