1922.] 205 



move or less triangular, figure with their inner edges in contact ; in 

 Hardya the plates stand at right angles to the valve and each is a large 

 equilateral triangle having its base equal to and in contact with one-half 

 of the free edge of the valve, consequently there is, in the cephalad 

 aspect, a large V -shaped space between them. The only extra-British 

 record for H. inelunopsis with wdiich I am acquainted is Irkutsk 

 (Jakovlev in litt.), Oshanin, Cat. 1908. The genera Ophiola, Mocydia, 

 Recilia, and Drylix are all well distinguished by their facies ; and the 

 removal of their components from the genera in which they are 

 commonly placed contributes to the homogeneity of the latter. 



The Comstock-Needham terminology has rendered possible the 

 intelligible use of characters derived from venation. The venation of 

 the elytra in Cicadina is much less stable than in some other groups, but 

 the instability is not sufficient to neutralize the phylogenetic significance 

 of venational characters. 



I distinguish Jassina from the other eight divisions of Jassidae as 

 follows : — Frontal sutures not meeting above the antennae ; ocelli on the 

 forehead, i. e. that part of the epicranium where the crown passes into 

 the frons ; M forked on the disc of elytra ; both edges of the outer face 

 of hind tibiae multi-spinose. 



JASSINA. 



1 (10) li2+3 in elytra running to tlie termen rather than the costa. Crown 



with a distinct keel at the hind margin, or separated from the frons 

 by a well-defined ridge, or strigose in front parallel with the free 

 sides. 



2 (3) Crown four-sided, bounded behind by a fine keel 



. . Grypotes Fieb. 



3 (2) Crown five-sided. 



4 (5) Ocelli nearly or quite touching the eyes Platymetopius Burm. 



5 (4) Ocelli evidently free from the eyes. 



6 (9) Crown separated from the face by a well-de fined ridge. 



7 (8) Pronotum separated from prosternum by a ridge. Crown with a deep 



impression parallel with its front edge .... Grophocraenis Thoms. 



8 (7) Sides of pronotum not margined. Crown refiexed in front 



. .Dorafnra J. Sahib. 



9 (6) No ridge separating the face from the crown, the latter strigo,«e in front 



parallel with its free sides. Face pale with a black chevron on the 

 upper half reaching from side to side Rhytistyliis Fieb. 



10 (1) R2+3 in elytra running to the costa. Crown ecarinate at the hind 



margin, not separated from the face by a well-defined ridge, nor 

 strigose in front parallel with its free sides. 



11 (20) Intermediate m-cu present. 



12 (13) Elytra with many irregular supernumerary white cross-veins. Crown 



widely rounded in front Jassus Fab. 



