Distribution of Moths of the Sub-family Bistonince . 163 



Fauna of to-day, by an examination of the Pliocene fossils of 

 Malta and Crete. These include abundant remains of elephants 

 and hippopotami. These forms argue the presence of con- 

 siderable land areas supporting enormous forests whilst the 

 latter animals prove that this land was intersected by many 

 noble rivers. 



If we appeal to present conditions, then the Arctiad genus 

 Ocnogyna, with its local species on all of the several portions 

 of this long lost continent, no matter how small, abundantly 

 proves the same proposition : and as equally weighty evidence 

 the existence of the Cedar of Lebanon ( Cedrus libani) in distinct 

 local races on Mount Lebanon in Syria, and in the mountains 

 of Northern Africa may be adduced. 



Over this land, far and wide, Zamacra flabellaria spread, 

 extending as far northward as Sardinia. Yet, when it occupied 

 the Pliocene Sardinian peninsula, the break up of Tyrrhenis 

 (adopting the name suggested for this sub-continent) had 

 already commenced. Whilst Corsica and Sardinia had been 

 disjoined from South France* since early Tertiary times, as 

 the paucity of Alpine plants and animals common to the 

 Maritime Alps and the two islands proves, and the number of 

 endemic forms like the butterflies Argynnis elisa and Papilio 

 hospiton found only in these two islands confirms, still for 

 ages they had been one as the presence of common endemic 

 forms shows. Nevertheless, when Z. flabellaria occupied 

 Sardinia, Corsica was even then an island and no passage was 

 open ; this early break between Corsica and Sardinia is ren- 

 dered the more vivid by the numbers of peculiar Corsican 

 species, exemplified by the moths Aegeria anthraciformis, 

 Ellopia pinicolaria and Orgyia rupestris, to be obtained. 



Toward the south-west, however, advance was still possible, 

 and following the routes traversed by such migrants as the 

 Painted Frog (Discoglossus pictus) and the Greek Tortoise, at 

 length Tunis was reached and immediately afterward Algeria 

 and Morocco colonised. At some period subsequent to this, 

 in the Moroccan area, the species Zamacra marocana has been 

 evolved from Z. flabellaria. 



When, finally, flabellaria reached its " furthest west," the 

 Straits of Gibraltar had already been formed and it found its 

 passage into the Spanish Peninsula closed ; its wanderings 

 thus had been much more delayed than many of the early 

 members of the first Oriental migratory wave. This would 

 indicate that the Straits of Gibraltar were formed not long 

 after the inauguration of the Pliocene epoch. Very probably, 

 it was their formation which initiated the slow break up of the 



* Unique forms like Aegeria aerifrons prove the former continuity of 

 Corsica and South France. 



1917 May 1. 



