242 F. W. EDWARDS. 



Blood- sucking. — ^No evidence. 



References and Synonymy. — The female I previously attributed to S. latipes really 

 belongs here, together with some of those I included with S. angustipes, but the female 

 I formerly regarded as this species is S. aureum. The pupa figured by Fries as 

 that of S. reptans may be this species ; also the pupal filaments figured by 

 Tomosvary (Rovartani Lapok, i, p. 34, 1884) and Horvath (loc. cit. p. 195, pi, iii), 

 though attributed to S. columbaczense, may belong to this species, as their structure 

 seems identical. In any case the S. columbaczense of these writers would seem to 

 belong to the same group as S. angustitarsis. Friederichs (Zeitschr. f. angew. Ent., 

 vi, p. 61, 1919) found the species in the river Aar at Bern and figures the male 

 hypopygium and the pupa and pupal filament ; the figures have be^n transposed 

 with those of S. maculatum (i.e., S. latipes). 



13. S. aureum, Fries* (figs. Ik, 2m). 



Larva. — General colour dirty greyish or greenish grey, with rather ill-defined 

 reddish-brown markings. Head with five or six well-defined elongate dark marks ; 

 two transverse on the posterior margin, three or four longitudinal in the form of 

 a cross, the middle one linear and sometimes divided (making six in all) ; all these 

 sometimes enclosed in a dark cloud ; a dark stripe over the eyes, including a distinct 

 blackish dot. Antennae with the first joint rather swollen, except on its apical 

 fourth, which is rather suddenly narrowed, second joint much more slender but not 

 greatly longer than the first, third half as long as the second, fourth minute. Mentum 

 with 11 sharply pointed teeth in the terminal row, the central one and the second 

 from each end much larger than the others. Two conical papillae on the ventral 

 side of the last abdominal segment. About 70 rows in the anal sucker, each with 

 12-15 hooks. Skin round anus bare. Gills simple. 



Pupa. — Respiratory filaments much longer than the pupa, four in number, all 

 arising almost at the same point, but all practically in the same plane ; all equally 

 though very slightly thickened towards the base. Cocoon constructed as in 

 S. latipes, but without any trace of a median anterior projection. 



Habitat. — Small temporary streams, especially when stony ; sometimes also 

 found in rivers, but not in great numbers. 



Breeding Season. — My observations are somewhat contradictory and unsatisfactory, 

 but there would appear to be at least two broods in the year, of which that appearing 

 in the early autumn is much the most numerous in individuals. The only definite 

 evidence available as to over-wintering is that Mr. A. H. Hamm took a female in 

 the Oxford Museum, 3.ii.l916. 



I found eggs, laid almost certainly by this species, in August 1915, in patches 

 on blades of grass at the surface of the water, and on stones below the water. 

 The eggs are dark brown and hard-shelled, not enclosed in jelly ; some which I 

 kept under a dripping tap hatched at the end of a week and the issuing larvae 

 had well -developed egg-bursters, resembling those of S. latipes. 



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

 in all the small streams round Harrow, Pinner and Northwood, viii. 1915 ; most of 



* See synonymy below. 



