CHIASMUS. 391 



Synopsis of Genera. 



A. Vertex as long as breadth bet-^een eyes ; 



posterior margins of tegmina rounded .... Ciijasmus, p. 391. 



B. Vertex shorter than breadth between eyes ; 



posterior margins of tegmiua truncate. 



a. Vertex about half the length of breadth 



between eyes, as long as pronotum ; 



posterior angles of tegmina acute Doratulina, p. 392, 



b. Vertex more than half as long as breadth 



between eyes, longer than pronotum ; 



posterior angles of tegmina rounded .... Kaiitwa, p. 394. 



Genus CHIASMUS. 



Chiasmus, Muh. if Rey, Ann. 'Soc. Linn. Lyon, 1855, p. 215 ; Melich- 



Horn. Faun. Ceylon, p. 163 (1903). . 

 Atractotvpus, Fieh. liev. May. Zool. (3) iii, p. 392 (1875) ; Melich. 



Cicad. Mitt.-Eur. p. 184 (1896). 



Type, C. transhicidus, M. & E., a Paloearctic species. 



Distribution. Palcearctic and Oriental Regions, 



" This genus is distinguished by the acutely angulated produced 

 and marginally sharpened vertex ; front with a flattened lono-i- 

 tudinal furrow at the point ; the teguiina are usually short, 

 parchment-like, not covering the abdomen, rarely developed, in 

 which case they are thin." {Melichar.) 



As at present I only know this genus from the Oriental Region 

 by a species described by Dr, Melichar, I have thought it best to 

 give his generic diagnosis, 



2661. Chiasmus uzelii, Melich. Horn. Faun. Ceylon, p. 164, t. iv, f. 7 a 

 (1903). 



" Body brownish-yellow ; vertex triangularly produced, between 

 eyes as broad as long, pointed at anterior border, flattened above 

 with a black quadrangular mark at tip in which is a short white 

 apical dash, behind this two large quadrangular black spots which 

 are rectangularly margined on the inner side and border, a paler 

 middle line not projecting behind to the front border of the pro- 

 notum ; eyes sessile, longly oval, brown ; face as long as the 

 breadth between the angles of the cheeks, pale yellowish with a 

 brown ( 5 ) to black ( J ) transverse band which runs in the 

 middle of the face from one eye to the other and colours the 

 antennal cavities black ; antennae pale yellowish ; on the upper 

 margin of the face are four brown or black marginal spots, of 

 which the inner ones are approximate on the tip of the face and 

 commonly coalesce into a blotch ; pronotum half as long as vertex, 

 very finely transversely stippled, white with two black dots in the 

 middle near the anterior margin and with several coalescing black 



