BIONOMICAL INVESTIGATION OF THE NORFOLK BROADS. 671 
One other species of Agrion lias come under my notice and that 
is Agrion armatum , Meyer, of which I took two specimens c? & ? 
at the end of May at Sutton. This species has not hitherto been 
recorded as British, although Mr. Edelsten tells me that he found 
it in the same locality in 1902. 
A species, Enallagma cyathigerum , has its centre on the 
Hickling, Horsey, and Martham Broads, and also occurs as the 
commonest species at Calthorpe. It is also to lie found at Sutton, 
Barton and Dilham on the Ant, and I have found a few specimens 
of the nymph at Acle Bridge on the Bure. The species, however, 
does not apparently occur west of Ant mouth on the Bure. The 
perfect insect frequents the edges of the open water of the Broads 
more than the other species, but in the autumn, that is about 
August, it deserts the open water and is to bo found along the 
dykes. 
Possibly Erythromma naia* will also ultimately turn out to be 
generally distributed, although up to the present I have only found 
it in seven out of the twenty-four sub-districts. It, however, occurs 
at Sutton, Calthorpe, Hickling and Wroxham, a wide enough 
range, although I believe that like Agrion pulchellum , it has its 
centre in the eastern portion of the district. 
I believe the range of Lestes sponsa agrees very much with that 
of Enallagma cyathigerum already referred to. It is a late insect, 
appearing on the wing about the middle of July and remaining in 
evidence well on into September. I first found the nymph at the 
beginning of June, after which it became very common. Although 
I searched for the imago in the Wroxham sub-district during 
August, the height of its season, I failed to find it, and I neither 
found imago nor nymph anywhere above Ant mouth on the 
Bure. 
Pyrrho soma nympliula is one of the earliest species on the wing, 
appearing about the middle of May. It also seems to have a short 
existence, as I did not find it after the end of June, and I fear 
therefore that my record of its distribution is more incomplete than 
that of other species. I have, however, found the nymph in 
several localities, and putting all the records together, I failed to 
find the species at Hickling, Horsey or Martham, but otherwise it 
seemed to be fairly generally distributed. 
The other species of this genus, Pyrrliosoma tenellum, is 
