230 F. W. EDWARDS. 



collected on stones in a rapid mountain stream at Kirkby Stephen, Westmoreland, 

 22.vii.1912 (C B. Williams). Inverleithen, near Peebles, 7.viii.l910, adult males on 

 the wing, larvae of various sizes and some pupae on stones and some on grass 

 (Dr. J. Rettie, per Dr. J. H. Ashworth). Various streams in the neighbourhood of 

 Pontesbury and Church Stretton, Salop, vii.1920. 



Blood-sucking. — No definite evidence, but a few specimens (of both sexes) entered 

 tent. 



References. — Friederichs, in the paper cited in the introduction (Oct. 1920), 

 describes this species from the Harz Mountains. I have distributed it to various 

 correspondents under the MS. name obreptans. 



5. S. reptans, L. (figs. Id, 2c, 4e). 



Larva.- — General colour greyish. Head with a single dark spot of varying size 

 and shape in the middle of the posterior margin of the clypeus ; no dark mark above 

 eye-spots. Abdomen with conspicuous dark greenish bands on all the segments 

 dorsally, those on 6-8 nearly confluent. No ventral papillae on last segment. 

 Gills each with 4 to 5 short branches. Skin round anus with numerous minute 

 almost colourless simple scales. Teeth of mentum rather blunt, the nine in the 

 terminal row all sUghtly trifid, the small lateral lobes pale. Antenna 5- jointed, 

 gradually tapering to the end of the 3rd ; first scarcely as long as the next two together, 

 second nearly twice as long as the third. About 75 rows of hooks in the anal sucker, 

 12-15 hooks in each row. 



Pupa. — ^Respiratory filaments much shorter than the pupa, 8 in number on each 

 side, spreading but little from the vertical plane ; arranged in 4 very shortly stalked 

 pairs ; uppermost pair rather shorter than the others ; all the stalks equal in length 

 and all the filaments of equal diameter, shghtly and evenly tapering towards the tips. 

 Cocoon as in S. ornatum, except that on each side towards the front there is a rather 

 large open space, usually crossed horizontally by one or two bands of silk. 



Habitat. — Swift shady rivers in mountainous regions, but not at high altitudes. 

 Where water-plants (such as Ceratophyllum) are present the larvae and pupae occur 

 on them in some numbers, but are most typically found on the flat upper surfaces 

 of large stones where the current is strongest, and particularly in those places where 

 the flow is smooth and even and where there is no great depth of water. No larvae 

 were found in the bare valleys above the tree-line, and very few in places where the 

 rocks were much covered with moss. 



Breeding season. — The first brood of the year does not appear until the end of May 

 or the beginning of June. I have had no opportunity of ascertaining whether there 

 is a second brood, nor what is the method of over- wintering. 



Material collected. — The species was abundant in Machrie Water and in the burn 

 flowing through Brodick Woods, Arran, v-vi.l919, in company with S. tuberosum. 

 It did not occur in the smaller burns on the island. Also found in Devonshire, 

 in small numbers in the Upper Teign and in the Yeo near Ashburton, and more 

 numerous in the Otter at Tipton St. John and in the Sid at Sidmouth, in the former 

 case in company with large numbers of S. variegatum, and in the latter with 

 S. ornatum and other species, 1-18. vi. 1920. A single male was taken on the wing 

 near Church Stretton, Salop, 21. vii.1920. 



