29 



1893, Hopkins, Bui. 32, W. Va. Agri. Exp. Sta., p. 214, No. 307. 



1895, Dyar, Trans. Am. Ent. Soc, pp. 301-302. 



1896, Marlatt, Bui. 3, (tech. ser.) Div. Ent. U. S. Dept Aeri 

 pp. 66-67. ^ * 



THE TWO MARKED TREE HOPPER. 

 Enchenopa binotata Say. 

 Order Hemiptera; Family Membracidae. 



This little tree hopper is very common in Ohio, and may be found at 

 any time from the first week in May until the end of the season. Its 

 favorite food plant is said to be the Hop tree (Ptelea trifoliata), but it 

 has also been observed feeding upon the bittersweet, grape, butternut, 

 white birch, red bud, black locust and on weeds. 



The adult measures, when full grown, three-tenths of an inch in 

 length, including the horn, and one-fifth of an inch without it. The gen- 

 eral color is a rusty-brown, with two bright pale yellow spots on the 

 ridge of the back just at the base of the horn. 



The small elongate, almost cylindrical, delicate green colored eggs- 

 are deposited, overlapping each other, in two parallel rows of sjx to 

 twelve each, in a slit made in the bark of the twig, and a thick, sticky, 

 viscid, white covering of stringy albuminous matter is placed over them 

 by the female. This covering of the eggs has often been mistaken for 

 insects, even by eminent entomologists, as it resembles very closely the 

 frothy excretions of several members of the family Cercopidse. These 

 masses measure about an eighth of an inch in length by one-tenth in 

 width, somewhat hemispherical in form, and the strings of albuminous 

 material are arranged in ribs, those on the one side meeting and lapping 

 slightly onto those from the other at the median line. These egg masses- 

 were observed on a black locust tree at Ontario, Ohio, September 3, 

 1904, the adults being quite numerous on the tree at that time. During 

 the following winter they were also noted on the Ptelea. The young 

 were first noticed at Columbus on the black locust on May 8, 1905, and 

 shortly afterward in large numbers on the Ptelea. 



The nymphs are gregarious in habit, clustering together at the base 

 of the tender twigs where they remain stationary for hours at a time. 

 When disturbed, however, they move very briskly, but it is claimed that 

 they do not acquire the power to jump until after the third molt. Those 

 observed measured about one millimeter in length; dark brown color 

 above, yellowish-brown below; the dorsal surface of abdomen covered 

 with white tipped spines arranged in five longitudinal rows, one occupy- 

 ing the median line and two on either side. Until the third molt they 

 lack the horn, which in the adult projects prominently above the head,, 

 giving them an appearance which some have likened to a bird. 



