May— July iSSq.J 



psrcHE. 



213 



Dicraiieura Hardy 

 Notus Fieber 

 Erythia Fieber 

 Typhlocyba Germar 



Erythro)ictira Fitch 

 Empoa Fitch 

 Idia Fieber 

 Ano77iia Fieber 

 Zyginla Fieber 

 Eupteryx Curtis. 



These genera may be very readily 



distinguished by the following synopsis : 



A marginal vein extending all around 



the posterior wing parallel with the 



margin. 



Elytra margined posteriorly. Alebra. 

 Elytra not margined. 

 Two apical cells in the posterior wing. 

 Dicranejira. 

 One apical cell in the posterior wing. 



Empoasca. 

 No marginal vein at the tip of the 

 posterior wing so that here the veins 

 end in the margin. 

 The hrst two longitudinal veins unit- 

 ing before reaching the margin. 



Typhlocyba. 

 All four veins attain the margin. 



Eupteryx. 

 North American species have been 

 described as follows: by Say (Proc. 

 acad. nat. sci. Phila., v. 4, 1S25 ; 

 Compl. works, v. 3, p. 259) four 

 species ; Harris (Encyclopaedia Amer- 

 icana 1S31 and Injurious insects 1841) 

 three species. Fitch (Rep. on state 

 cab. nat. hist., N. Y., 1S51) and (Third 

 report on the noxious and other insects 

 of the state of New York 1S56) eight 

 species; Stal (Stett. ent. zeit. v. 19, 

 p. 195-196) three species Walsh as 



cited above thirteen species. Uhler 

 (Bull. U. S. geol. surv. v. 3, 1S77) one 

 species and Forbes (13th rep. 111. state 

 entomologist 18S4) one. 



To Alebra belongs aztrea^ pallida 

 and binotata of Walsh but the descrip- 

 tions are so meagre that no one can cer- 

 tainly say that they are distinct. I know 

 cjuite a number of very pretty forms of 

 this genus still undescribed. 



Of the described forms of the genus 

 Empoasca we may make four groups of 

 what may be but four species. The first 

 includesya(5a^ of Harris, viridesceiis con- 

 sobrlna and malejica of Walsh and /?/;-« 

 of Stal which are uniform green witlTOut 

 markings. Second obttisa and maligna 

 of Walsh which are certainly not distinct 

 from each other but difter from the first 

 in having a much more obtuse vertex. 

 Third albopicta of Forbes which is dis- 

 tinguished by the white markings on the 

 vertex. And fourth the brilliant aiirca- 

 viridis of Uhler. 



Dicranezira is represented by abnor- 

 mis of Walsh and ca;-/;^«/a of Stal which 

 may not be different. 



In the genus Typhlocyba we have one 

 of the most variable species in existence 

 as regards the coloring, the so-called 

 grape thrips Typhlocyba vitis of Harris. 

 Just how many of the forms described 

 as distinct species of this genus will be 

 found to be varieties, of course it is im- 

 possible at present to say, but certainly 

 half of the colored species so far de- 

 scribed have been definitely made out 

 to be varieties. The colored species are 

 vitis of Harris basilaris, comes, obli- 

 qua, and trifasciata of Say, vulneratcr., 

 tricincta.^ coccirzia., vitifex and affiuis 



