IN THE NORFOLK BROADS DISTRICT. 59 
was to first discover the local distribution or localisation of 
species, and then to inquire into the cause of such 
localisation. I referred to the results of my first year’s work 
in the district, and showed that there was a very distinct 
localisation in the case of most of the species of the thin- 
bodied Dragon-flies, some having their centre of distribution 
in the eastern part of our district, others in the western part, 
while one or two species were confined to very circumscribed 
areas. 
I have continued these observations upon the Dragon-flies 
during the past season, and have noted one or two changes 
in the distribution of the species, but I have made no attempt 
to consider the question of causes, deeming it best to continue 
the observations for several years before going further, 
because, in a group such as this, the material is necessarily 
scanty, and it is only by the accumulation of facts that we 
can hope to discover the localising agencies. 
One further reference to my last year’s paper before I proceed 
to the subject in hand. It may be remembered that I proposed 
to divide up the whole district arbitrarily into twenty-four 
sub-districts, without any reference to faunistic or physical 
characteristics. After further consideration, and also after 
consultation with several members of this Society, I have 
come to the conclusion that such a division is both inconvenient 
and unnecessary ; inconvenient because, without publishing 
a somewhat detailed map, there is no way of concisely defining 
the sub-districts, and unnecessary because the parochial 
divisions of the district would seem to be quite as suitable 
as 'those which I proposed to make. Further, I am now 
uncertain as to the utility of any such division under all 
circumstances, and I propose in this paper to sub-divide the 
district according to the exigencies of the case. 
Now’ to come to the subject in hand. During the past 
season I have been collecting the Water Beetles of the Broads 
district. I commenced the work in February, selecting 
certain areas of ground, in the dykes and pools of which 
I made collections. I revisited these stations as far as 
possible month by month until November, and also collected 
