278 [December, 



ON THE DISTRIBUTION OF NONAGRIA BREVILINEA, Fenn, 

 BY F. D. WHEELEE, M.A., LL.B., F.E.S. 



We have so often to notice tbe diminution or disappearance of 

 local species, sometimes perhaps from the injudicious attentions of 

 collectors, though far more frequently, I think, from the gradual 

 change of climatic conditions, &c., that it is refreshing to place on 

 record an instance of the contrar}' tendency. 



N. hrevilinea is in no sense a mere local variety, being abundantly 

 distinct both as imago and larva, in its appearance and habits. It may 

 claim to be one of the most local of moths, being apparently unknovpn 

 on the continent, save for a recent capture in Belgium, while in this 

 country it is (so far) absolutely confined to the Norfolk Fens. 



I may mention that these Fens, roughly speaking, are divided 

 into three parts : (1) a long strip eight or ten miles long, following 

 the course of the Bure from Wroxham to South Walsham, and varying 

 in width from half a mile to, perhaps, two miles ; (2) a detached 

 portion of considerable extent, including Barton, Sutton, and Irstead, 

 of very similar character to the first, but separated from it by some 

 four miles of drained marshes bordering the lower course of the river 

 Ant ; and (3) a still larger portion surrounding Hickling Broad, 

 Whitesley and Heigham Sounds, and at Horsey and Waxham coming 

 quite close to the sea, separated from the Bure fens by an interval of 

 several miles of drained land, but at Catfield coming within about 

 two miles in a direct line of the second section. These Hickling fens 

 differ to some extent in appearance and flora from the others, being 

 less wooded, and consisting chiefly of vast reed beds and drier tracts 

 covered with Cladiiim mariscus, amongst which the very local Lastrea 

 cristata still grows in some plenty on mossy hillocks rising above the 

 general level. 



N. hrevilinea was first discovered in 1864 at Eanworth, in the 

 heart of the first named section of fens. In 1871 Mr. Barrett and I 

 took the second recorded specimen, though we afterwards found that 

 Mr. King captured three or four specimens the same year at Horning, 

 the next parish. From that time onward the locality was worked 

 more or less every season, and N. hrevilinea occurred in most years — 

 at first as a great rarity, though in 1874 Messrs. Farn and Jenkinson, 

 by persistent work, secured a nice series. The first capture in any 

 quantity, however, was by Mr. W. H. B. Fletcher in 1878, all these 

 being on the original spot. From that year onward I have found the 

 species in numbers fluctuating, but on the whole increasing, and it is 



