6 M. W. NIELSON 



Coelidiine leaf hoppers vary in size from about 4 mm to nearly 14 mm and in 

 shape from slender (Tharrini) to robust (Teruliini). In general habitus they 

 often resemble some issid or ogeriine fulgoroids by virtue of their narrow heads and 

 broad elytra. Many species are brightly coloured but most are fuscous to 

 testaceous, particularly the elytra. 



The head, which varies in length and width in relation to the pronotum, is 

 always narrower than the pronotum in all tribes except for one genus in the tribe 

 Teruliini. More important is the length and shape of the crown, particularly 

 that portion distad of the anterior margin of the eyes, which may be even with 

 the anterior margin of the eyes or extend distally to one-half or more of its entire 

 median length and vary from rounded to broadly or sharply angulate. Of similar 

 value is the disk of the crown which may be slightly depressed or distinctly elevated 

 above the level of the eyes (Tharrini) and with the lateral margins distinctly 

 carinate or not, and/or parallel or convergent posteriorly. Numerous striations 

 are present on the disk which radiate posteriolaterally at a point near the middle 

 of the apex and are particularly prominent in Tharrini. The ocelli vary in 

 position and are situated anteriorly in broad-headed forms and laterally in long- 

 headed forms. The eyes are unusually large and vary in the amount of lateral 

 tumescence in relation to the entire dorsal area of the head. The posteriolateral 

 portion often overlaps the anteriolateral margin of the pronotum. 



On the face the clypeus is the most diagnostic character for many groups and 

 varies in shape and tumescence. Longitudinally, the clypeus occupies a major 

 portion of the face but is usually broader anteriorly than posteriorly. The lateral 

 margins are sometimes ca'rinate anterior to the antennal fossa. Along the 

 anterior margin the surface is rugulose in the Tharrini and Thagriini. There is 

 a median longitudinal carina in some species of Tharra, and its presence (Teruliini) 

 or absence (Coelidiini) conveniently separates these tribes. The clypellus is short 

 and the lateral margins are usually parallel or expanded apically in most forms. 

 An unusual feature occurs in many species where the anterior portion is very broad 

 and tumescent. 



The pronotum is short and broad but rather uniform in length and medially is 

 often shorter than the scutellum. There is a dorsopleural carina in all genera 

 except Sandersellus, which is bicarinate. A medial carina which varies from 

 complete to incomplete is present in a few species among most of the tribes. On 

 the surface of the pronotum are many bullae or knobs in nearly all forms. 



The scutellum is very large in relation to the pronotum among all groups except 

 the Tinobregmini and one species of Tharra. In the Tinobregmini the posterior 

 margin of the pronotum overlaps the anterior margin of the scutellum and base 

 of elytra, giving a distinctly smaller appearance to the scutellum. 



The forewings vary in length from brachypterous in the Tinobregmini to normal 

 in the remaining tribes. Almost without exception, venation is prominent and 

 incomplete, lacking M 1 + 2 and cross vein m— Cu 3 (outer anteapical cell closed). 

 Several species of Thagria have two closed anteapical cells. Five apical cells 

 are present in all tribes. The appendix varies from well-developed to nearly 

 lacking in only a few species. The hind wings have not been studied thoroughly 



