1919] 



ECONOMIC ZOOLOGY ENTOMOLOGY. 



253 



In experiments with leaf hoppers as carriers of lire bli.^ht {BaciUus amylov 

 orous), positive results were obtained with the aiiple leaf hopper hut no infec- 

 tions were noted in similar efforts with the other species. 



A number of natural enemies were observed, including Anngrus armatus 

 which parasitizes the egg. Control measures consist chiefly in protection 

 through spraying with soap and nicotin mixtures to combat the yoimger 

 nymphs. The destruction of weeds which harbor the insects serves as a supple- 

 mentary measure. 



"In a series of spraying tests in which soap, nicotin, and kerosene emulsion 

 were also compared, a high degree of effectiveness was indicated for a spray- 

 ing mixture of nicotin sulphate 1 pint, lumi) lime 60 lbs., copper sulphate 4 lbs., 

 and water 100 gal." 



The life histories as observed at the station are illustrated in the following 

 diagram (tig. 2) : 



Fig. 



-Diagram of life histories of leaf hoijpers injurious to apple trees as observed 

 at Geneva, N. Y. 



Leaf hoppers injurious to apple trees, F. H. Lathrop {New York State Sta. 

 Bui. Jf51, popular ed. {1918), pp. 3-6, fig. 1). — A popular edition of the above. 



A new genus for Tettigonia trifasciata (Homoptera; Euptergidae), W. L. 

 McAtee (I'ror. Biol. Soc. Wash., 32 {1919), pp. 121-123. figs:. 2), 



Preliminary key to the Nearctic species of Eupteryx (Homoptera; Euptery- 

 gidae), AY. L. McAtee {Ent. News, 30 {1919), No. 7, pp. 182-186). 



Some studies on the eggs of important apple plant lice, A. Peterson {New 

 Jersey Sfns. Bui. 332. pp. 5-63, fig.?. 17). — This detailed report of investigations 

 on the structure, behavior, and susceptibility of the eggs of three important 

 aphidids found on apple trees {Aphis avenee, the apple aphis, and A. sorbi) is 

 summarized in part as follows: 



A morphological study of the eggs of these three apple plant lice " shows two 

 distinct layers in the eggshell, an outer semitransparent layer which is soft 

 and glutinous when the egg is deposited, but hardens and becomes somewhat 

 tough (maybe brittle) and impervious upon long exposure to weather, and an 

 inner, soft, t^lastic, membranous, black layer. A third layer, thin and mem- 

 branous, may be seen about the nymph when it starts to emerge. This skin is 

 probably the first exuvium, since it is shed by the nymph as it emerges. 



" Under out-of-door conditions the outer layer of the egg usually splits along 

 the dorsomesal line a number of days (2 to 30 or more for A. aveiur) before 

 the nymph emerges. So far as observed under greenhouse conditions the eggs of 

 all three species split their outer covering at least a few hours before the pig- 

 mented layer is severed. In 1918 the first eggs of A. avenw with split outer 

 132688°— 19 5 



