126 Mr. R. M‘Lachlan’s Monograph of the 
greyish-ochreous. Mesothorax dark blackish-fuscous. Anterior 
wings greyish-yellow, faintly clouded and reticulated with pale 
greyish-fuscous ; a large yellow elongate spot on the dorsal 
margin just before the anal angle, and the apical margin is regu- 
larly spotted with yellow and greyish-fuscous alternately; these 
markings are most distinct in the female. Posterior wings grey, 
subhyaline, iridescent; fringes grey. Legs greyish-ochreous. 
Abdomen fuscous, paler beneath; greenish in the female during 
life. In the male the upper margin of the last abdominal segment 
is fringed with long yellow hairs ; app. inf. with a long and straight 
up-directed basal joint, pale yellow, with an oblique brown line at 
the apex, where there is a tuft of brownish-yellow hairs, terminal 
joint very small; penis long and slender, cylindrical, yellow, the 
apex much thickened and directed abruptly downwards, brown. 
In the female there is a broad fuscous lobe proceeding from the 
upper margin of the last segment, with a small semicircular notch 
on the middle of its anterior edge; lateral valves large, nearly 
quadrate, yellow, the margin excised. 
Expanse of fore-wings 6—74 lines. 
Very common in autumn along the Thames about Kingston; 
occurs at Ringwood and Exeter; also in North Wales, Ireland 
(Loch Derg), &c., but apparently not generally distributed. 
After having compared specimens of this insect with types of 
H. angustata and H. lepida, Pictet, Dr. Hagen informs me that 
he is doubtful if our species be identical with either, but adds that 
it is certainly the lepzda of his synopsis in the Ent. Ann. 
B. Third joint of the maxillary palpi shorter than the fourth. 
Antenne as long as or longer than the wings, the joints 
of the basal portion marked with oblique dark lines. (Large 
or middle-sized species. ) 
a. Eyes small. Vertex transverse, much broader than 
long. 
2. Hydropsyche pellucidula, Curtis. 
(Pl. VIL. fig. 2, neuration, palpi, leg, antenna; Pl. XIII. 
figs. 8, 9, app.) 
Philopotamus pellucidulus, Curt. (*) Phil. Mag. p. 213, 8 (1834); 
Hydropsyche pellucidula, Steph. (*) Ill. p. 172, 4; Philopo- 
tamus lanceolatus, Curt. (*) Phil. Mag. p. 213, 10 (1834)?; 
Hydropsyche tenuicornis, Steph. (*) Ill. p. 171, 2 (1836) ; 
Kol. Gen. et Spec. Trichop. pt. 2, p. 234, 5?; H. hibernica, 
