1 63 



Derbidae. 



This family ccMitains the most deUcate and remarkable forms 

 of the Fulgoroidea, or even of the Auchenorhynchi. While such 

 forms as Nisia and Philadclphcia seem to have little in common, 

 there are numerous intermediate forms which render sharp g-roup- 

 a! separation difficult. There seem to be two main subfamilies, 

 viz: (i) Nisiinae. represented hyNisin in which the last segment 

 of the labium is comparatively elongate, and the anal vein of the 

 clavus strongly granulate, and (2) Derbinae represented by 

 Philadclphcia, in which the last segment of the labium is annuli- 

 form, generally a little wider apically than basally, and the anal 

 vein not granulate, the latter division being much more numerous 

 in genera and species. Unfortunately in the genera Thyrocepha- 

 liis, Basilcoccphalus and Phacioccphalns, we have a small inter- 

 mediate group in which the anal vein is granulate and the last 

 segment of the labium annuliform. 



In the following table of Australo-Fijian genera. I have en- 

 deavoured to include those recently described by Distant. As the 

 latter mentions the shortness of the apical segment of the labium 

 as a character of the (sub-) family in the Oriental forms, (he 

 includes Nisia in which it is comparatively elongate!), I have sup- 

 posed that his Australian genera have the same character. 



I La,st segment of labium somewhat elongate, (anal vein and 

 head granulate ) (^) 



1 a Last segment of labium annuliform (4) 



2 Head strongly carinate along the middle. .. .3 Phaconeiira 

 2a Head not medianly carinate (3) 



3 Lateral keels of frons parallel i Nisia 



3a Lateral keels of frons narrowing basally as seen from below 



2 Suva 



4 Anal vein of tegmen granulate (*) (5/ 



4a Anal vein simple (''' ) (7) 



5 Pronotum more or less normal ; vertex anteriorly truncate 



6 Thyrocephalus 



5a Pronotum laterally laminate, sinuate, recurved, partly en- 

 closing antennae; vertex not truncate anteriorly .... (6) 



(*) Distant has not mentioned in anv of his descriptions a most important charac-- 

 ter, viz.: The granulation of the claval veins and of the head, etc., so that I have 

 arranged his genera under the second division, except Urabunna, in which his artist 

 seems to have recognized the importaiice of the claval granulation, and which is only 

 a synonym of Bnsilfocephalug. 



