12 M. W. NIELSOX 



it should be pointed out that the system does not work for the Coelidiinae, neither 

 on a worldwide basis nor in a restricted geographical region. Linnavuori's 

 (1960a; 19606) treatment of the genera Tharra, Coelidia and Muirella is a case in 

 point. 



A discussion of the generic relationships of Coelidiinae, and its relationship to 

 other subfamilies of Cicadelloidea by Evans (1971) is based on the assumption 

 that Wagner's (1951) system of classification is correct. Evans holds that many 

 genera of the Coelidiinae s.l. such as Placidus, Placidellus , Kasinella, Caelidioides, 

 Iturnoria, and Malagasiella would lose their relationships to Coelidia if they were 

 removed to other subfamilies. I have found no basis to suggest that these and 

 other genera which I excluded from Coelidiinae are so related to Coelidia when in 

 fact there are numerous other genera much more closely related to the nominate 

 genus. 



The final establishment of the subfamily interrelationships in the Cicadellidae, 

 or relationships at higher levels is somewhat premature in \ iew of our overall 

 lack of knowledge, especially of peripheral groups that have been split off as a 

 result of taxonomic studies of several subfamilies, viz. Cicadellinae, or subfamilies 

 that have been studied very little, such as the Evacanthinae. Moreover, there are 

 doubtless many undescribed genera in the tropical regions of the world which, 

 when studied and described, may provide ample evidence to show intersubfamily 

 relationships heretofore unknown. I have elected not to follow the hierarchical 

 classification of Metcalf (1964) in which he gives a family status to the Coelidiinae, 

 for the reasons described above and for those advanced bv Oman (1949) and Young 

 (1968). 



In consideration of all the changes discussed above, a more complete concept 

 of the subfamily as redefined follows. 



Head almost always narrower than pronotum; eyes large, posteriolateral angles overlapping 

 anteriolateral margin of pronotum; crown usually narrow, often produced distad of anterior 

 margin of eyes, disk often elevated above level of eyes and usually striate radially, sometimes 

 carinate laterally; ocelli near anterior margin of crown, near lateral margins above eyes in 

 long-headed forms; pronotum short, surface knobbed, dorso-pleural line carinate (bicarinate 

 in Sandersellus) ; scutellum large (exception : Tinobregmini) ; elytra elongate (exception : 

 brachypterous forms of Tinobregmini), usually broad apically, venation incomplete, outer 

 anteapical cell closed (two closed anteapical cells in several species of Thagria) ; wings with 

 costal margin expanded basally; clypeus elongate, usually broad anteriorly and tapered 

 posteriorly, sometimes tumescent, often with median longitudinal carina; clypellus short, 

 lateral margins sometimes broad anteriorly but usually expanded posteriorly or parallel; legs 

 with spinulation well developed, posterior femoral setal arrangement 2:2:1, male valve 

 always fused ventrally to pygofer; pygofer usually bears one or more pairs of processes on 

 caudal margin; tenth segment sometimes with pair of processes; aedeagus usually asymmetrical 

 and usually with secondary processes or spines; connective Y-shaped, articulated basally to 

 aedeagus; styles usually long, often with secondary processes, sometimes asymmetrical; plate 

 entire, large, elongate, narrow to broad (segmented subbasally in Tharrini and Thagriini), 

 sometimes appressed laterally, sometimes glabrous, sometimes setose or with macrosetae. 



