84 ANNALS OF SCOTTISH NATURAL HISTORY 



H. tristis, Payk. Coll and Mull, fairly common. 



H. umbrosus, Gyll. Coll, one or two ponds only, but common 

 there. 



H. gyllenhalii, SchiiJd. Coll and Mull, common. 



H. morio, Dej. Mull (800 feet), common. 



H. palustris, L. Coll (scarce) ; Mull, Tobermory river. 



H. erythrocephalus, L. Coll and Mull, scarce. 



H. melanarius, Sturm. Coll, one only ; Mull, several on peat 

 mosses. 



H. memnonius, Nic. Coll, not on peat. 



H. obscurus, Sturm. Coll and Mull, common. 



H. nigrita, F. Coll and Mull, not common. 



H. discretus, Fairm. Coll, very local, but common where it occurred ; 

 Mull, several in small trickling stream. 



H. pubescens, Gyll. Coll and Mull, the commonest species; it 

 occurred in 60 per cent of the collections on Coll ! 



H. planus, F. Coll, a few in one or two brackish pools. 

 H. lituratus, F. Coll, not common. 

 Agabus guttatus, Payk. Mull. 



A. paludosus, F. Coll and Mull, in weedy slow-flowing streams, 

 common in such situations. 



A. congener, Payk. Mull, common at high and fairly low altitudes 

 on the peat. 



A. arcticus, Payk. Mull (700-800 feet), common. 



A. sturmii, Gyll. Coll, scarce ; Mull, two or three with A. arcticus, 

 congener, etc., at 825 feet. 



A. chalconotus, Panz. Coll, scarce ; Mull, only in one collection. 

 A. bipustulatus, L. Coll and Mull, common. 



Ilybius fuliginosus, F. Coll, scarce ; Mull, a few, Tobermory river, 

 etc. , 



I. oenescens, Thorns. Coll, scarce ; Mull, once only, with A. sturmii, 

 arcticus, congener, etc., at 825 feet. 



Rhantus bistriatus, Berg. Coll and Mull, fairly common. 



Colymbetes fuscus, L. Coll, only in one or two ponds. 



Dytiscus punctulatus, F. Coll, not common. 



D. marginalis, L. Mull, one in a peat hole. 



D. lapponicus, Gyll. Mull, taken by various collectors. 



Acilius sulcatus, L. Coll, in one deep peaty hole, several specimens. 



