W. L. MC ATEE 269 



a value of .033 nun. in the focal plane. The measurements or 

 ratios g,iven are median length of vertex (LM), length straight 

 across vertex from anterior angle of eye (LE), width between ant- 

 erior angles of eyes (WA), greatest width of head (WP), dis- 

 tance from median point of posterior margin of vertex to anterior 

 angle of eye (OA), from same point to posterior angle of head 

 (OP), from same point to posterior angle of pronotum (OH), 

 median length and greatest width of pronotum, and distance from 

 humeral angle of tegmen to point nearest apex of scutellum and 

 from thence to apex of tegmen. Unless otherwise stated mea- 

 surements are from type specimens. 



Key to the Groups of Species 



For the purposes of this key, and throughout the paper, the 

 apical cells and cross-veins of tegmina are given numbers, in 

 order according to their position from costal to radial margin. 

 The cross-veins are, respectively: one, between costal margin and 

 first sector; two, Ijetween first and second sectors; three, between 

 second and third sectors; and four, between third sector and rad- 

 ial margin. 



A. Normally the thinl sector and third apical vein are not contimious, a 

 portion of the angulate or curved third cross-vein being interjMsed between 

 them, the fom-th ajncal cell, therefore, being angulate or curved at base. 

 (Figs. 7 to 10.) 



B. Normally the base of the fourth ajjical cell is distinctly angulate. 

 (Figs. 7, 9, 10.) 



C. Second apical cell distinctly shorter than third, and a fourth or more 

 shorter than fourth apical cell (fig. 7); vertex rather long and pointed. 



(Fig. 5.) Group 1 



CC. Second apical cell about the same length as third; not a fourth 

 shorter than fourth. CFigs. 9, 10.) 



D. Normally half or more of third cros,s-vein Iiordering fovn-th apical 



cell, which is unusually wide and hicks a black dot near base. Group 3 



DD. Normally less than half of third cross-vein borders fourth apical 



cell, which is narrower and almost invariably is black or has a black 



dot at base Group 4 



BB. Normally the base of the fourth apical cell is a smoothly curved line 



(fig. 8); vertex of medium length and acuteness (fig. 4) Group 2 



AA. Normally the third sector and the third apical vein are continuous, and 



the fourth apical cell is merely oblique or rectangular at base. (Figs. 11, 12.) 



B. Fourth cross- vein normally oblique, joining radial margin so that 



posterior angle formed by their juncture is less than a right angle (fig. 11) ; 



apex of second apical cell not marked with black Group 5 



TRANS. AM. ENT. HOC, XLVI. 



