1l4 Mr. R. M‘Lachlan’s Monograph of the 
which the apices of the anterior wings are inflexed in repose. 
Besides this character, the absence of spurs on the anterior tibia, 
the presence of costal crotchets, the arrangement of the veins and 
of the anal appendices, all prove this genus (as restricted) one of 
the most natural in the Order. It is probable that Latreille in- 
tended it to comprise the allied species of Leptocerus, Setodes, &c., 
but as his typical species belongs here, the name can be very 
justly retained. 
1. Mystacides atra, Pictet. (PI. XII. figs. 27, 28, app.) 
Mystacides atra, Pict. (*) Recherch. p. 109, 9, pl. 11, fig. 4 
(1834); Hag. (*) Ent. Ann. 1860, p, 75, 71; MM. ater, 
Burm. Handb. p. 919, 4; Brauer (*), Neurop. Aust. p. 41; 
Leptocerus nigricans, Steph. (*) Ill. p. 195, 4 (1836). 
Antenne blackish, the basal portion annulated with white, but 
not conspicuously. Palpi dull black. Head and mesothorax 
shining black. Anterior wings black, with a metallic lustre; the 
veins darker. Posterior wings smoky-black, subhyaline, with 
paler fringes. Legs dark dull-brown. Abdomen blackish-brown. 
In the male there is a triangular membranous lobe (little evident 
in dry specimens) from the middle of the upper margin of the last 
abdominal segment; on either side of this is a needle-shaped 
app. Intermed. ; app. sup. long and very fine, slightly hairy; app. 
inf. broad at the base, the apical portion claw-shaped and curved 
upwards, dark testaceous; ventral plate produced in the middle 
into a short slightly forked lobe. In the female there is a supe- 
rior membranous median lobe, with a semicircular emargina- 
tion, and with a short straight finger-shaped appendage on either 
side; lateral valves very large, narrow at the base, the apical 
portion very greatly dilated. 
Expanse of fore-wings 8—9 lines. 
Larva slender, of a clear fawn-colour, with black spots forming 
X-shaped markings on the head and two first thoracic segments. 
Metanotum with two black points. Abdomen fawn-coloured, 
with very small respiratory filaments. Legs fawn-coloured, 
spotted with black. (Pictet.) 
Case thin, formed of vegetable remains and grains of sand, with 
twigs placed longitudinally on the outside. (Pictet.) 
Frequent in standing and very slowly running waters, and ap- 
pears in summer and autumn. 
