350 THE ENTOMOLOGIST. 



distributed in these islands which is not equally so in Ger- 

 many, but that traces still exist of several more ancient 

 Faunas and Floras which are now confined to small and 

 separate areas. 



Forbes argued for the existence of four such sub-Floras : — 



1. A Mediterranean Flora in the west of Ireland, derived 

 from Spain, over land which we must suppose formerly 

 bridged the gulf of seven hundred miles, which now separates 

 Ireland from the Iberian peninsula. 



2. The Flora of the mountain-tops of Scotland, Cumber- 

 land, Wales, and the North-west of Ireland, derived from 

 Scandinavia and Iceland, and supposed to have reached our 

 shores either by means of icebergs or over land of which the 

 Orkney, Shetland and Fa^roe Islands are the last remains 

 above water. 



3. A Kentish, or chalk Flora. 



4. A Norman Flora, confined to South-western England 

 and South-eastern Ireland. 



Mr. Birchall suggested that the following species [of Lepi- 

 doplera], several of which occur in the utmost profusion in 

 the district of Western Ireland, where the peculiar Spanish 

 Flora is found, and are scarce or non-existent outside that 

 very limited area, are remnants of the old Peninsular or 

 Mediterranean Fauna: — Zygaena nubigena, Erastria argen- 

 tula, E. fuscula, Lilhosia caniola, Dianthcecia Nisus, D. 

 Cassia, and Notodonta bicolor. 



He exhibited a number of Lepidoptera from the mountain 

 regions of England, Scotland, and Ireland, and was of 

 opinion that such species as Cry modes exulis, Zygaena 

 exulans, Pachnobia alpina, Psodos trepidaria, Anarta cordi- 

 gera, A. melanopa, and many others, had certainly reached 

 our shores from Scandinavia and Iceland. 



As regards Forbes's third and fourth subdivisions, he did 

 not think any evidence was to be obtained by a consideration 

 of the Lepidoptera inhabiting the district in question. There 

 was, no doubt, a general similarity in the species found on 

 the opposite sides of the English Channel, and there are a 

 few conspicuous insects, probably of French origin, which do 

 not wander far from our southern coast, but there seems no 

 reason to assign a remote date for the naturalization of such 

 insects as Sphinx Nerii, Deilephila Euphorbiae, Plusia 



