10 U.S. NATIONAL MUSEUM BULLETIN 261 



such genera as Cuerna and Oncometopia, which are obviously closely 

 related in other morphological characteristics. When the metepimeron 

 is exposed, in some genera it may have a flattened, angular, shelflike 

 projection which extends laterally above the meron. 



The legs off'er more characters than are vised in the present classi- 

 fication. The anterior tibiae are broadly flattened and dilated in some 

 genera. The posterior femora in most taxa of leafhoppers bear chaeto- 

 taxal characters at the apex of the femur (fig. Ib-e), as first shown by 

 Ribaut (1952a). These characters tend to be much more variable in 

 Cicadellinae than in other subfamilies of leafhoppers. They are much 

 more variable in the Proconiini than in the Cicadellini, although varia- 

 tion in the latter tribe has already been demonstrated by Frediani 

 (1954, 1956). There is always at least a pair of setae at the apex of the 

 posterior femur. Rarely, there are three setae in this position. More 

 basally there may be one, two, or three setae. If two or more are 

 present proximal to the distal pair, they are almost always arranged 

 serially. A very unusual arrangement of the apical setae of the posterior 

 femora occurs in some Proconia species. These are discussed under that 

 genus. The posterior femoral setal arrangement is expressed herein- 

 after by a formula, e.g., 2:0:0 (paired apical setae, none more proximal 

 to these) (fig. lb), 2:1:0 (paired apical setae, one more proximal) 

 (fig. Ic), 2:1:1 (paired apical setae, and two serially arranged more 

 proximal setae) (fig. Id), or 2:1:1:1 (paired apical setae, and three 

 serially arranged more proximal setae) (fig. le). The length of the pos- 

 terior femur, whether or not, with the legs at rest position, it extends 

 forward far enough so that the hindknee (femorotibial joint) attains 

 the posterior proepimeral margin, is a character which has been pre- 

 viously used in cicadellid taxonomy; it is found to be quite useful in 

 the present classification. The shape of the posterior tibia, whether in 

 cross section it is quadrilateral (fig. If) with the sides more or less equal 

 in length, or whether it is greatly flattened, is useful in classification to 

 some degree. Each of the angles of the posterior tibia bears a row of 

 large setae in this subfamily. There is some variation in the arrange- 

 ment of the very large posterior tibial setae. For descriptive purposes, 

 the rows of setae on the posterior tibiae have been numbered (fig. If). 

 The innermost of the tibial setal rows, located on the surface of the 

 tibia which lies distal to the adlateral of the paired apical femoral setae, 

 in rest position, is designated row 1. The tibial row of setae located 

 distally from the ablatcral of the apical pair of femoral setae is desig- 

 nated row 2. Continuing around the tibia in the same direction are 

 rows 3 and 4. The useful taxonomic characters have been found in 

 tibial rows 1 and 2 of the posterior tibiae. Row 2 may consist entirely 



