New York Aghicultueal Expekimext Statiox. 373 



round and near the apex of the wings; another on the costal 

 margin, which is nearly rectangular and is about half the distance 

 from the base to the apex of the wing, another on the inner 

 margin about one-fifth the distance from the apex to the scutellum. 

 The black spots on the elytra remain constant during the insect's 

 life, but the yellow markings are subject to change. The bright 

 yellow of summer turns to salmon before the insects leave the vine 

 in autumn, and by winter the markings become red. These indi- 

 viduals change again to yellow in the spring after the insects have 

 been feeding on the grape. 



The variety octonotata differs from the typical comes in having 

 a broad, dark median stripe on the scutellum (the triangular piece 

 at the base of the wings) and has a large dark spot on the inner 

 margin near the base of the "wing." During 1911 there were less 

 than one-tenth as many of the variety octonotata in the vineyards 

 as of the typical comes. On certain varieties of grapes (which 

 are listed later) T. comes is practically absent but its place is 

 taken by another species T. tricincta^ Fitch which is rather 

 striking in appearance. This species is seldom found on the Con- 

 cord in Chautauqua county and so cannot be called a common 

 insect. So far as it has been studied its life history is similar to 

 T. comes and it is apparently susceptible to the same treatment. 



FOOD PLANTS. 



The several species of grape leaf-hoppers doubtless fed origin- 

 ally on the various species of wild grapes that are indigenous to 

 the Lake Erie valley. Since T. comes and T. tricincta differ in 

 the variety of grapes each infests the food plants of each species 

 will, for the sake of clearness, be discussed separately. T. comes 



1 This species is slightly larger than T. comes and may be recognized by 

 the following characters: Across the elytra there are three dark bands. The 

 band at the apex is dusky, except a dark spot, and covers the apical fourth 

 of the elytron. The middle band extends across each wing cover, being sub- 

 triangular. The outer portions are composed of a black spot almost rec- 

 tangular in shape and situated about one-half the distance from the base to 

 the apex. From this spot the band widens until it reaches the inner margin, 

 being a dark red. The third band extends across the base of the elytra, the 

 scutellum and the posterior part of the prothorax, and varies from red 

 to purple. The eyes and sides of the prothorax are purple. 



