THE AUCHENOREHYNCHOUS HOMOPTERA. 171 



and, finally, in Arceojms they are notably shorter and coarser, 

 and also far more closely set than the other small bristles of the 

 segment ; at the same time they have preserved entirely the 

 character of bristles. ' 



The bristle-shaped part of the flag;jallum is^metimes rela- 

 tively \on^{Calliscelis) , sometimes shore \Falgora,°Tettigometra); 

 sometimes with very distinct segmentation throughout the whole, 

 or in great part of its lengi^^Ti^tigometj-a^ArceojyuSyMegamelns), 

 sometimes without segmentation {Fidgo7~aYlssu^Calliscelis). 



While the condition of the flagellum does not appear to have 

 any wider systematic significance, on the other hand the detailed 

 structure of the sensory organs on the second segment of the 

 peduncle appears to possess such a value to a pre-eminent degree. 

 I must lament that I have not been in a position — from want of 

 material — to examine a far greater series of special genera. 

 The Delphax group, so sharply characterized in other ways, 

 appears also admirably defined by its antennal structure ; on the 

 other hand, I am not in a position to say tlraft ^Tettigometra is 

 clearly so distinguished, since I am without the forms which 

 Stal places in their neighbourhood : moreover, I cannot define 

 sharply marked boundaries for the Ricania-Flata groups, and I 

 have not been ableito exan^i^ micro scopicall)\, any examples of 

 the Stalian gron^s^ Acltilida, Tropiduchida ana Derhida. There 

 thus remains a considerable gap in my researches. 



B. Tegulfc and Wings. 



Tegulse are found only in the Fulgoridse. In this family 

 they are, moreover, almost universally present, generally readily 

 enough seen, but sometimes covered over by the lateral margins 

 of the prothorax. Stal says (Hemipt. Afr. 128) that they are 

 absent rarely, but does not mention the precise genera in which 

 this is the case. The only genus examined by me, in which I 

 have not been able to see them,\^-^Calliscelis, a genus charac- 

 terized, among other things, by the strongly reduced wings. 

 Their presence is thus typical of, and peculiar to, the Fulgorid 

 family, but at the same time they can be absent or reduced 

 almost to the vanishing point (which is certainly concomitant 

 with a great reduction in the flight organs), so that their absence 

 -is not an absolute character. 



I have^but little to add on the subject of Wing -New ation. 



In tli'e ^Cercopidce a part of the anterior margin of the 

 posterioy" wings (in ^Cercopince and Aphrophorince near the base 

 itself, in Maclicerota in the middle between the retinaculum and 

 the base) is expanded into a triangular projection (pi. ii. f. 2 a), 

 whose upper and outer margin bears a few posteriorly directed 

 hooks, which are fixed on a thicker, firmly chitinized base 

 (f. 2 a). On the under side of the tegmina, a little behind the 



