INSECTS INJURIOUS TO THE GRAPE 



521 



The adult hoppers are about one-eighth inch long and the 

 wings are prettily marked with yellow and red as shown in Fig. 

 375. " In summer the young and adult insects are light yellowish 

 in color, but before going- into hibernation, the eyes of the adults 

 darken and the peculiar yellow spots on the wings change to an 

 orange red, thus giving the hibernating adults a general reddish 

 appearance. These darker markings on the adults vary so much 

 that nine different varieties are now recognized, two of which are 

 represented at 6 and c, in Fig. 375. Often several of the varieties 



FIG. 375. Grape leaf -hopper (Typhlocyba comes): a, adult female; 6, adult 

 male; c, another form of the species, showing variation in markings; 

 d, newly-hatched nymph; e, last stage nymph; /, appearance of injured 

 leaf; g, cast pupa skins a, e, much enlarged; g, less enlarged; /, reduced. 

 (From Marlatt, U. S. Dept. Agr.) 



may be found together on the same vines, but usually one color 

 form largely predominates." The nymphs are a light yellowish- 

 green color with lemon-yellow stripes on each side of the body. 

 They pass through five molts before becoming adults, the wing- 

 pads gradually getting larger in the later stages. No very similar 

 insects are common on the grape, so that the pest is readily recog- 

 nized. 



Life History. The adult hoppers hibernate over winter under 

 leaves, grass, or trash in or near the vineyard, in neighboring 



