224 F. W. EDWARDS. 



Pupa. — ^Respiratory filaments about as long as the pupa, on each side 8 in number, 

 arranged in 4 shortly stalked pairs, the stalks of the two ventral pairs usually the 

 longest ; ventral pair slightly thinner than the others ; all the filaments more or less 

 in one plane (the vertical). Cocoon tough, closely woven, about twice as long as its 

 breadth in front ; height and breadth about equal ; anterior margin thickened, but 

 without any forwardly- projecting piece in the middle ; no floor to the front half of 

 the cocoon, which has its mouth widely open, and entirely covers the pupa. 



Habitat. — ^Principally a river species, but occurs also in small streams, some- 

 times even those of a temporary nature. Where water-plants are present, the 

 larvae and pupae attach themselves to the plants, and show a preference for those 

 with long narrow leaves, such as Sparganium and water-grasses ; Ranunculus is less 

 favoured, Potamogeton less still ; usually the larvae are found chiefly on the lower 

 sides, the pupae chiefly on the upper sides of the leaves. In the smaller streams, 

 where water-plants may be few or absent, the larvae and pupae are to be found on 

 or under stones or on any suitable objects. The species is rarely met with in 

 streams less than 4 feet in width. 



Breeding Season. — ^This species appears to breed in suitable localities all the year 

 round, almost regardless of the season. Pupae have been collected in every month of 

 the year except January, from the middle of February until Christmas. On one 

 occasion (19.ii.l917) fully developed pupae were collected immediately after a period 

 of three weeks continuous frost ; these produced adults of both sexes a few days 

 later. I took a newly emerged male in the open on 1st March 1919. There appear 

 to be three main broods, in April, July and September. 



Material collected. — Larvae and pupae have been collected as follows : — Bucks : 

 R. Misbourne, near Denham, 10.ix.15. ; Burnham Beeches, iv. 1916, a few in stony 

 stream with S. latipes. Middlesex: Harefield, 21.ix.l5, in stony and weedy 

 stream ; Pinner, 22-24. viii. 15. Surrey : Beddington, near Mitcham, 31.vii.l9 ; 

 larvae in millions in river Wandle, pupae also numerous, but no adults seen ; a few 

 pieces of leaf (totalling one yard in length) of Sparganium simplex carried approxi- 

 mately 500 pupae and 4,000 larvae, apparently all of this species. Devon : Larvae, 

 and pupae numerous in many small streams in the valleys of the Dart and Teign, 

 up to a height of 1,000 ft. ; also in the rivers Otter and Sid, and in small runnels 

 on the sea-clifTs near Sidmouth, vi. 1920. Hants : New Forest, l.v.1920, a few in 

 small streams and in Beaulieu River, in company with large numbers of var. 

 nitidifrons ; River Test {M. E. Mosely). Herts. : River Chess, near Chorley Wood, 

 30 .viii. 15 ; River Lea, near Hatfield, v.1916 and 12.iii.l917, on Ranunculus; 

 Pegsdon, 21.iv.l6, on grass in small stream in " The Meg," larvae very large and 

 very variable in colour ; Hitchin, 5 iii.l5, under stones in stream 2-3 inches deep ; 

 Radwell, 24. v. 20, larvae of all sizes, very variable in colour, also some pupae, on 

 stones in small rapid streams ; R. Ivel, near Baldock, vi.l917, on Ranunculus, Spar- 

 ganium, etc. Beds. : Barton, 21.x. 16, under stones. Camhs. : Bartlow, Hinxton, and 

 Ashdon, 2.x. 15, on grass and willow rootlets in small streams, none on stones in 

 stream bed ; Wittlesford, 29.xii.15 and 3.vii.l6, larvae on stones in small stream ; 

 Stapleford, 28.iv.16, on grass at edge of small stream ; Shepreth, 19.ii.l7 and 14.iv.l7, 

 on Ranunculus and Oenantke in small stream ; R. Granta, near Hauxton, 7.iv.l7, 

 on sedge at edge of river ; Cambridge Botanical Gardens, 1 .x.l5, one pupa with 



