62 MR. F. BALFOUR BROWNE ON AQUATIC COLEOPTERA 
occurred in 57 % of all the collections, while the latter has 
occurred in 14 %. H. planus, in its best month, November, 
was present in 28 % of the collections, while H. erythrocephalus 
was less common in May than in any other month, when it 
occurred in 46 % of the collections. 
Again, Hydroporus gyllenhalii, Schiodte, is described in the 
Norfolk list as common, while two localities only are given 
for H. granulans, L., which therefore is presumably to be 
considered as either rare or very local. From March to 
November of last year H. gyllenhalii did not occur in any 
month in as many collections as did H. granulans, its best 
percentages being in March and May (18), while H. granularis 
was at its lowest percentage, 16, in June, and occurred in 
33 % °f the collections in September and October. 
In the same list Agabus bipustulatus, L., A. chalconotus, Panz, 
and A. sturmii, Schon, are all described as abundant, although 
the first was more than twice as common as the last, and five 
times as common as the second in the Broads district last 
season. 
However, it is not my object to discuss the insufficiencies 
of the Norfolk list, but to point out that such a list, which 
is typical of most local lists, is of little use as a basis for working 
upon. We are not told the years or the months in which the 
records were made, and it is common experience that species 
are continually changing their habitats and varying in 
abundance. 
However, a very novel and unscientific use has recently 
been made of this Norfolk list by Mr. Claude Morley in a 
paper published in the last number of our Transactions. 
Mr. Morley published a list of the Coleoptera of Suffolk in 
1899, an( f i n th e paper to which I refer, he endeavours 
to compare the Beetles of that county with those of 
Norfolk. 
Our county list was published in 1893, and although 
several supplementary lists have appeared since then, only 
one, published in 1899, adds any species to the list of Norfolk 
Water Beetles, and of the four records there mentioned, one 
or two are old ones which had been overlooked when the 
