THE WATER-BEETLES OF WOOD AVALTON FEN. 68 



Hydroporus doysalis F., common. 

 „ lineatiis F., coaimon. 



„ gyllenhali Schioclt., common. 



,, vittula Er., scarce. 



,, palufitris L., common. 



,, eri/throcephalus L., common. 



,, pubescens GylL, common. 



„ planus F., common. 



,, lituratus F., common. 



Af/abus abbreviatiis F., not uncommon in one ditch only. This is 

 a very interesting capture, as it was formerly abundant in the Fen 

 districts, and is evidently a survival. It is tJie Askham Bog species, 

 where it is usually abundant (Beare and I found it in plenty when 

 there together a feAV years ago), but I am not aware that it has been 

 found anywhere else in Britain for many years with the exception of 

 Cambridgeshire, where it is recorded from Chatteris and Holwoods by 

 Fryer; and two specimens were taken by Dollman,at Soham, October 

 24th, 1912. 



Af/abits sturuii GylL, common. 



,, bipiKstulatus L., common. 

 Platauibiis riiaculatiis L., common. 

 llybiiis fenestratus F., common. 

 ,, ater DeG., common. 

 ,, obscariis Marsh., common. 

 Copelatus ay His F., common. 

 lihantus grapii GylL, scarce. 



„ exoletus Forst., abundant. Many specimens are very dark 

 beneath. 



Pihantns adspersus F. ? I captured a specimen of a i?/mni«<s like 

 exoletus, and was struck by the black markings beneath, but unfortu- 

 nately I let it drop and lost it. Having broken my net I was unable 

 to hunt further. This specimen may have been B. adspersus, the 

 locality being very suitable, but on the other hand much fishing on 

 subsequent occasions failed to produce more, and as I have already 

 pointed out, many specimens of /?. exoletus which were taken were 

 dark beneath. 



Colynibetes fuscus L., common. 



Dytiscus maryinalis L., not very common. It was curious that this 

 was the only species of the genus that occurred. At Wicken four 

 species may often be found together. 



Hydatieus transversalis Berg., very scarce. This is a local and not 

 common species. 



Hydatieus seminiyer DeG., not rare. Also a local species. 

 GyrinuH elongatus Aube., scarce. A local species. 

 ,, marinus GylL, abundant. 



Hydrophilid^. 



Liuinebius truncatelliis Th., common. 



,, picinns Marsh., common. This is a very local species. 



Hydrochiis carinatus Germ., scarce. This very local species has 

 only been found in very few localities in Britain. 

 Ochthebius jiyymaeiis F., common. 

 Hydraena testacea Curt., scarce. 

 „ riparia Klug., abundant. 



