LEAF HOPPERS INJURIOUS TO CEREAL AND FOEAGE CROPS 



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The adult insects (fig. 8, a) are small, robust creatures, with a 

 rather distinctly pointed head and with the fore wings broad and 

 rather short in many cases, exposing the tip of the abdomen beyond 

 the end of the wings. They are dark brown, with distinct light 

 markings and a fairly distinct band across the wing base and again 

 back of the middle of the fore wings. They are a trifle more than 

 one-eighth inch in length. 



The nymphs (fig. 8, g) are rather slender and have a distinctly 

 angular head. They are colored much as in the adult, but the ar- 

 rangement of the markings is different. There is a narrow middle 

 line of white extending from the tip of the head to the end of the 

 abdomen, where it widens and 

 nearly covers the tip. A broad 

 stripe extends along the side from 

 the eye back to near the tip of the 

 abdomen and an indistinct narrow 

 one extends from the inner margin 

 of the eye, broken by white spots, 

 one on the posterior end of each 

 abdominal segment ; a second row of 

 dots lies midway between the first 

 and the marginal stripe on each side. 



Although the broods are not very 

 definitely separated, it would seem 

 from the observations made that the 

 first brood of nymphs occurs from 

 May until the early part of June, the 

 adults of this brood from the last 

 week in May until the middle of 

 July. The second brood nymphs 

 are present from the last week in 

 June until the first week in August. 

 while the second brood of adults, 

 beginning to appear about the mid- 

 dle of July, extends through Au- 

 gust; a third brood of nymphs, 

 appearing first about the middle of 

 August, develops during August and 

 September, and the third group of 

 adults, beginning to appear in early September, survives through Oc- 

 tober. From this life history it is obvious that it will be difficult to 

 fix upon any time at which mowing of the grass would be distinctly 

 effective in exterminating the species; consequently direct treatment 

 with hopperdozers or sprays or the effect of general rotation of crops 

 must be depended upon as the principal means of control. 



This species has been found to be quite extensively parasitized 

 by the small hymenopterous parasites of the family Dryinidae. At 

 one time at Cedar Point, Ohio, about 20 per cent of the individuals 

 collected showed the presence of the little external sacks of these 

 parasites. Doubtless they constitute an important factor throughout 

 its range in keeping the species reduced in numbers. 



Figure 8. — Say's leaf hopper (Delto- 

 cephalus sayi) : a, Adult, X 10 ; b, 

 face ; c, vertex and pronotum ; d, fe- 

 male genitalia ; e, male genitalia ; f, 

 wing ; g, nymph. (After Osborn and 

 Ball) 



