I9I2. Browne. — Aquatic Coleoptera of S.E. Irelaiid. 13 



species will help to show this intermediate type of dis- 

 tribution. 



WD ED LD AN WD ED LD AN 



FE TY ARDO FE TY AR DO 



WMSL LE MO WMSL LE MO 



EM RO CV LH EM RQ CV LH 



WGNG LF WHME WGNG LF WH ME 



SG KG KD DU SG KG KD DU 



CI. NT QC CW WI CL NT QC CW Wl 



NKLK ST KK WX NK LK ST KK WX 



SK MC EC WA SK MC EC WA 



WC WC 



Helophorus nubilus, F. Rhantus exoletus, Forst. 



We are therefore faced with the question why, if these 

 south-eastern species are part of the " Irish " tj^pe, are they 

 localised in the south-east corner of Ireland ? On the 

 question as to whether the localisation is due to some 

 environmental factor the general distribution of the species 

 is important, and w^e have in this group an extraordinarily 

 heterogeneous collection. For instance, H. ohlongus has 

 a distribution from France in the south through northern 

 Europe (Sweden), Siberia and North America. A. femoralis 

 is found in the Balkan Peninsula, Italy, Germany, France, 

 Belgium, Russia, Finland, Sweden, and Siberia, and Rh. 

 Grapii has much the same range. H. namis occurs in 

 northern Siberia and various countries southward to the 

 Mediterranean district, while A. conspersus only reaches 

 Denmark in the north, being found chiefly in the Medi- 

 terranean district {e.g., Sardinia, Corsica, Italy, Sicil}^ and 

 North Africa) extending eastwards as far as India. 



This heterogeneity alone is sufficient to throw doubt on a 

 suggestion of the localisation being due to a climatic factor 

 and a comparison of eastern Irish climatic conditions with 

 those in Britain and the Continent makes it even more 

 improbable that climate has been the localising agent. 



A 4 



