176 BRITISH CIGADM. 



segments, I apprehend will render specific identifica- 

 tion with fossils from distant areas very difficult. In 

 their diagnosis, chief stress is necessarily laid on the 

 wing-nem^ation, which, though fragmentary, is often 

 very delicate and distinct. 



The following modern genera are closely represented 

 either in a fossil state, or preserved more completely 

 in amber nodules : — Cicada, Cixius, Olearus, Delphax, 

 Apltrophora, Tettlgonia, Bijthoscopiis, Agallia, Thamno- 

 tettix, Cicadida, Acocephalus, and many foreign genera 

 of the FulgoridaB. 



In my Plate F, fragments of some fine and large 

 Cercopidae are figured. They were discovered in the 

 insect-beds of British Colmnbia.* 



The Psyllidge are fairly represented in rocks of the 

 Tertiary period ; but the Coccidae have been little 

 noted. Of other Homoptera the Aphidae are numerous. 



Miocene Period. 



Before 1865, the date of the publication of ' Die 

 Urwelt der Schweitz,' only thirty-three species of insects 

 were known from the Miocene beds of that country ; 

 but, subsequently. Prof. Heer discovered more than 800 

 from the shales of (Eningen near Schaffhausen alone. 

 Of these species, 543 were beetles and 636 Hemiptera. 

 Out of 822 specimens of Hemiptera, about 800 examj)les 

 were in the larval state, amongst which there was the 

 interesting early and single occurrence of a caterpillar ; 

 with numerous ants and grasshoppers. The presence 

 of at least one large Cicada, and the numerical j^ro- 

 minence of Eeduviidas, Scutata, and Coreodeae ; the 

 occurrence of several fine species of Cercopid^, and large 

 water-bugs, give good evidence that a warmer climate, 

 and especially a milder winter, prevailed over Central 

 Europe than is now found. Prof. Heer thinks that as 



'•' See contributions to the ' Fossil Insects of Canada,' Geol. Survey, 

 Yol. ii. 



