226 F. W. EDWAKDS. 



(Letcli worth, 5.iv 18) on horses' belhes, and (Letch worth, 19.x. 17) in numbers on 

 calves' bellies, some containing blood. Besides this I have frequently taken females, 

 sometimes apparently gorged, in cowhouses. Mr. W. Evans has noted the species 

 biting his hand. I have also myself received bites from them on my nose, eyebrow 

 and hand (25.iv.16, 19.X.17, 15,xi.l7, 5-18iv.l9). The bites were not particularly 

 painful and left no after-effects ; most of them were inflicted while I was in a stooping 

 position (e.g., when gardening), and I frequently noticed that the flies were more in 

 evidence then than while I was standing. Perhaps they mistake a man stooping 

 for a horse or cow, which would seem to be their normal hosts. 



References. — The early stages of this species have been described in more or less 

 detail by a number of writers. The best figure of the pupa is that of Castellani 

 and Chalmers (Manual of Tropical Medicine, Ed. iii. p. 812) ; the figure is not named 

 specifically as that of S. ornatum, but is quite unmistakeable. A larva and pupa 

 of S. ornatum have also been figured by Kollar (Sitzb. k. Akad. Wiss. Math. -Nat. 

 Kl. i, pp. 92-107, pis. i-iii, 1848, under the name S. sericeum, Mg .) ; Griinberg (Die 

 Siisswasserfauna Deutschlands, 2a, p. 107, figs. 128-130, 1910); Verdat (Naturw. Anz. 

 allg. Schweiz. Ges. v, p. 65, 1822 — as S. sericea) ; Liebe (Zeits. Naturw. 82, p. 345, 

 1910— larva only) ; Meinert (K. Danske Vid. Selsk. Skr. (6) iii, p. 373, 1886). 

 The most recent writer is Friederichs (Zeits. f. angew. Entom. vi, pp. 61-83, 1919), 

 who figures the male hypopygium and the pupal filaments of this species as S. reptans; 

 with this use of the name reptans I cannot agree. It is not clear what species he would 

 indicate as S. ornatum ; possibly the one described below as S. suhornatum. 



la. S. ornatum var. nitidifrons, nov. (fig. 4c). 



Closely resembles S. ornatum, Mg., except that the frons of the female is shining 

 and not dull ; the mesonotum of the female appears distinctly more shining than in 

 the typical form ; and there is little or no white on the hind margins of the abdominal 

 segments. The male does not differ perceptibly from that of S ornatum. Larva 

 with the head markings rather more distinct. Pupa with eight branches to the 

 respiratory organs, all about equal in diameter, arranged in four pairs, all almost 

 sessile or with very short stalks of about equal length. 



This form was abundant in the New Forest at the beginning of May 1920 ; larvae 

 and pupae were collected on different water-plants in the Brockenhurst River, the 

 Beaulieu River, and some small streams running into the latter. In the small streams 

 it was the most abundant form Specimens of the normal form of S. ornatum 

 were also reared from the same streams, but these were comparatively scarce. A 

 few females were taken on the wing at Gidleigh Park, S. Devon, 2.vi.l920, but no 

 larvae or pupae were found. Both sexes were reared from pupae found in company 

 with S. ornatum near Shelve, Salop, vii.1920, on grass in a small stream. 

 Dr. G. Enderlein has since sent me specimens of both sexes (identified as S. reptans) 

 from Berlin ; he also sent specimens, probably from the same batch, to 

 Friederichs, who has described them as S. reptans. 



This form bears a great resemblance to the Scotch and Welsh S. monticola ; the 

 latter is regarded as a distinct species, since it differs markedly from ;S. ornatum 

 in the larvae, pupae and male hypopygium, whereas the New Forest form apparently 

 does not. 



