20 Mr. R. M‘Lachlan’s Monograph of the 
A not uncommon species in the metropolitan district, frequent- 
ing ponds and canals, probably generally distributed. Appears 
at the beginning of May, and lasts for some weeks. 
When it first emerges from the pupa the wings are almost 
colourless, and the veins not darker. The type of O. chloroneura 
of Rambur was in that condition. 
Genus AcrypniA, Curtis. 
Antennz not very robust, basal joint stout. Head transversely 
quadrate. Eyes very prominent and large. Maxillary palpi in 
the male compressed, with short rounded basal joint, second 
third and fourth joints long, the last somewhat ovate. Labial 
palpi with very broad almost quadrate basal joint, second joint 
shorter and smaller, third joint longest, narrow. Prothorax 
hairy. Mesothorax scarcely broader than the head. Anterior 
wings elongated, rather narrow, dilated before the somewhat 
obliquely truncated apex, with very short and sparse hairy cover- 
ing, costa rounded; neuration moderately distinct, not differing 
in the sexes, radius with avery slight bend (in 4. Pagetana) before 
the termination, discoidal cell narrow, first apical cell reaching 
one-third along the discoidal, fifth acute at the base. Posterior 
wings subhyaline, with elliptical apex, first apical sector united to 
the radius by a transverse vein; discoidal cell short, broad and 
almost triangular. Legs moderately stout, tibiz and tarsi almost 
spineless; spurs short, of equal length. Abdomen in the male 
much dilated towards the extremity, broad and somewhat de- 
pressed, terminal segment fringed with long hairs, and furnished 
with long corneous appendices ; penis broad, with needle-shaped 
sheaths. 
Larva inhabits marshes and still waters. Case “ consisting of 
root-fibres of equal length, arranged close together in a spiral 
turned to the right.” (Hagen.) 
We have but one species in this country, which has, at first 
sight, the appearance of belonging to the Lzmnephilide. 
The typical specimen in the British Museum, from which 
Curtis’ figure was taken, has a remarkably broad and depressed 
abdomen, and Dr. Hagen seems to think that it has been acci- 
dentally pressed flat (Ent. Ann, 1859, p.71); it would, however, 
appear that the abdomen has a tendency to assume this flattened 
appearance, at any rate after death, as I possess several speci- 
mens in which the depression is almost as great as in Curtis’ 
type. 
