0LIARU8. 16 



number, and position of the costal granules of the 

 elytra. Though this is a convenient help to the iden- 

 tification of species, it can hardly be looked upon as 

 Natural ; and indeed it is not claimed by him to be 

 such. However, when a species has been once proved, 

 we may, for general purposes and convenience, fall 

 back upon such external characters. 



For the like assistance I also tabulate certain 

 characters, the scheme being based on Mr. James 

 Edwards' plan. 



The wings of the Cixiidas appear to have an expan- 

 sion beyond their apparent need as flying organs. 

 They may be regarded more as means for suspension 

 than for progression in the air. With the exception of 

 Oliarus, all the British species are granulated on the 

 nervures. The elytra, when at rest, are folded horizon- 

 tally, and parallel to each other ; and then the insect 

 has much the appearance of a minute moth, shaped 

 like a Noctua. 



The wings have no limbus, and their nervures are 

 not spotted. The disposition of tbe venation is 

 pretty constant throughout the species, but, as shown 

 in my Plates, the right and left wings do not always 

 correspond. Less material specific characters may be 

 sought in the colours of the face or mask, which lies 

 prone or horizontal to the ground, when the insect 

 walks. 



The female ovipositor consists of two serrated 

 plates enclosed in an open sheath, which is again sup- 

 ported between two horny valves, the five parts together 

 forming a single tube, which is very evidently seen 

 when viewed from above. These terminal parts are 

 commonly covered by a cottony or a waxy mass. 

 Fieber says the abdomen in Cixius " est exception- 

 ellement tronque et porte dans ce cas chez la femelle, 

 un fa^eau de flocons cretaces." 



The two genera may be thus separated : — 



