156 Mr. R. M‘Lachlan’s Monograph of the 
dark brown above, ochreous beneath. In the male the lobe from 
the upper margin of the last segment is very long and nar- 
row, band-like, with a dilated truncated apex ; app. sup. flat and 
short, placed on each side of the lobe, and [ am not certain but 
that these appendices have a moveable piece attached, concealed 
under the lobe; app. inf. very long, the basal joint longest, the 
terminal joint notched a little before the obtuse apex on the upper 
edge ; sheaths usually curved strongly downwards; penis nearly 
cylindrical. In the female the valves are large and somewhat 
hairy, the truncated apical margins slightly excised. 
Expanse of fore-wings 10—13 lines. 
Larva with the head yellowish, with a blackish marking in front 
oneach side before the eyes; an assemblage of brown spots on 
the middle of the dise forming a stellate marking; hinder edge 
notched, narrowly dark brown. Pronotum yellowish, broadly 
margined with brown on the hinder edge. Meso- and meta-nota 
and abdominal segments dull greenish when alive, the respira- 
tory filaments pinkish. Legs yellowish, with brown spots; anal 
crotchets yellowish, with blackish lines. : 
Inhabits clear swiftly-running streams, all over the country ; 
appearing from the end of spring tll late in the autumn. 
The true R. vulgaris of Pictet is very closely allied to this spe- 
cles, but appears to be distinct; nevertheless the characters are 
by no means striking. In vulgaris the penis-sheaths are always 
curved upwards, and the penis itself is more crooked and pro- 
vided beneath with a large obtuse tooth or tubercle; but I have 
seen examples of dorsalis in which the sheaths had an upward 
tendency. R. vulgaris probably occurs here, but is overlooked. 
2. Rhyacophila obliter:ta, M‘Lachlan. 
(Pl. I. figs. 8, 8*; Pl. VIII. fig. 6, neuration and palpi; 
P]. XIV. fig. 9, app.) 
Rhyacophila obliterata, M‘Lach. Ent. Ann. 1863, p. 134, fig. 7. 
Antennz brownish, with paler annulations. Head and palpi 
brown. Mesothorax dark reddish-fuscous. Anterior wings pale 
yellowish, faintly reticulated with pale grey, and with brownish- 
grey spots, somewhat arranged in two transverse rows; a large 
brownish-grey blotch, with ‘well defined edges, placed on the 
dorsal margin near the base, marks the inner edge of the pale 
dorsal blotch ; a distinct whitish hyaline dot at the thyridium ; 
veins brown; in the female the wings are narrower and pale 
brown, with indistinct yellowish irrorations, the dot at the thy- 
