THE LUSITANIAN FAUNA. 3OI 



it undertook the migration southward, just as the 

 English Channel and the Irish Sea could not have 

 been there when it wandered to England and Ireland. 

 The species which occurs in the south of England 

 has a wide range in Ireland, and reaches in Scotland 

 its most northern European limit of distribution. 

 Platyarthrus is only one of the Lusitanian genera of 

 woodlice. In Ireland chiefly on the west coast we 

 also find a brilliantly coloured Woodlouse, which is 

 absent from Great Britain, viz. Metoponorthuscingendus. 

 It reappears again on the Continent in the south of 

 France. Its range is therefore suggestive of a Lusi- 

 tanian origin ; and indeed, when we examine the 

 general distribution of the genus Metoponorthus, we 

 find that out of the forty-four known species, fully 

 one-half arc confined to Western Europe and North 

 Africa. 



My friend and colleague, Mr. Carpenter, informs 

 me that among the Irish Spiders he is acquainted 

 with, the following are to be looked upon as Lusi- 

 tanian species : 



Dysdera crocota. Agroeca celans. 

 Oonops pulcher. do. gracilipes. 



Tegenaria hibernica. Teutana grossa. 



Theridion aulicum. Cnephalocotes curtus. 



Lasseola inornata. Porrhomma myops. 



Of the Coleoptera, the genera Trichis, Glycia, and 

 Singilis, all belonging to the Running Beetles (Cara- 

 bidce], are almost confined to the Spanish penin- 

 sula. 



