﻿THE GRAPE LEAFHOPPER IN THE LAKE ERIE VALLEY. 



S3 



one instance of parasitism was noted. In tliis instance, on July 31, 

 1907, Mr. P. R. Jones, of the Bureau of Entomology, observed the 

 female of Aphelopus sp. in the act of thrusting her ovipositor into 

 the body of a nymph. No attempt was made to determine if eggs 

 were deposited in the body of this nymph, nor was any further evi- 

 dence of parasitism of the nymphs or the adults of the grape leafhoppcr 

 observed. 1 



On the other hand, the nymphs seem to be especially subject to the 

 attack of many predaceous insects, mites, and spiders, while the 

 adults become entangled in spider webs and are 

 preyed upon by the occupants. 



The literature on the grape leafhopper con- 

 tains the following records of attack by preda- 

 ceous enemies on either the nymphs or the 

 adults : 



B. D. Walsh, in 1862, records Ilemerodromia 

 superstitiosa Say, one of the dance flies, as feeding 

 on the " hoppers " in Illinois. 



Townend Glover, in 1875, records Hydliodes 

 vitripennis Say, the glassy-winged soldier-bug, 

 as feeding on the nymphs. 



M. V. Slingerland, in 1902, records a mite, 

 Rlvyncholophus parvulus Banks, the larvae of 

 Chrysopa, and aphis lions as feeding on the 

 nymphs. 



J. H. Quayle, in 1908, records the destruction 

 of the nymphs by the beetles and larvae of lady- 

 birds, aphis lions, and ants, but states that all 

 of these predaceous enemies put together have little apparent influ- 

 ence in lessening the number of the pest. 



During the investigation of this pest at North East, Pa., aphis 

 lions, ants, mites, and spiders were frequently observed preying upon 

 the nymphs, and in addition, to them a very active orange-colored 

 mite (Anystis agilis Banks) was often found feeding upon the nymphs 

 and occasionally upon the adults, especially just after the latter had 

 transformed and had not the full use of their wings. Both the nymph 

 and the adult of a capsid of the genus Diaphnidia near D. Jiamata 

 Van Duzee were frequently found with nymphs of T. comes impaled 

 on their long probosces. Yet all of these predaceous enemies com- 

 bined failed to have any appreciable influence in reducing the destruc- 

 tive numbers of the leafhopper. 



i While Mr. J. F. Strauss, of this bureau, was making drawings of adults of T. comes for this paper he 

 found an adult among some material in alcohol with the pupa of a dryinid (see fig. 13) attached to the body. 

 These specimens were collected by the writer in vineyards near Euclid, Ohio, Aug. 9, 1911. 



Fig. 13.— Adult grape leaf- 

 hopper parasitized by a 

 dryinid, and showing 

 cocoon of parasite pro- 

 truding from abdomen, at 

 left. Greatly enlarged. 

 (Original.) 



