New Zealand Hydroptilidae (Order Trichoptera). By Martin E. Mosely, F.E.S. Communicated by R. J. Tillyard, M.A., D.Sc. [Read before the Nelson Institute, 19th December, 1923: received by Editor, 31st December, 1923; issued separately, 28th August, 1924.] New Zealand Hydroptilidae have attracted little attention, and only one species, Oxyethira albiceps McL., has been described. Even for this species the description is incomplete, as no drawings of the genitalia have hitherto been published. A year or two ago Mr. Jack Henderson sent home a dozen or so of these little insects, and it was at once apparent that O. albiceps was by no means the only representative of New Zealand Hydroptilidae; and in a small collection sent me from the Cawthron Institute, Nelson, by Dr. R. J. Tillyard, with the request that I should describe any new material that I might find included in it, I found that there was, besides O. albiceps, at least one species distinct from those which Mr. Henderson had sent. Three species form a group by themselves, and, although they have certain characters resembling those of Oxyethira, yet they differ consistently in other respects, and furnish material for a new genus, described as follows:— Paroxyethira n. g. Spurs 0, 3, 4. Ocelli present. Head furnished posteriorly with two large lobes or caps. Antennae in ♂ with 32 to 41 joints, according to species. Palpi as in Oxyethira. Wings long and slender, apices very acuminate and generally furnished with tufts of white and also black hairs. In both anterior and posterior wings the sector (according to MacLachlan's nomenclature) is forked twice and upper branch of cubitus once, as shown in fig. 1. Abdomen of ♂ having terminal dorsal segment excised with a wide deep U-shaped excision extending nearly to base of segment, exposing the penis in the cavity thus formed, and in one species a complicated arrangement of asymmetric, strongly chitinized teeth. Superior appendages with apices directed towards each other and generally concave. From base of seventh ventral segment arises a process either broad and short or long and slender, according to species, and thickly covered with hairs. Sixth ventral segment armed with a tooth. Abdomen of the ♀ resembling Oxyethira. Paroxyethira tillyardi n. sp. (Figs. 2, 3, 4, 5.) Length of anterior wing, ♂, 3.5 mm. Antennae about 36-jointed in ♂; last dorsal segment excised as above; superior appendages very short, armed at extremities each with a short blunt finger-like tooth, directed inwards. In dorsal cavity can be seen, in balsam preparation, a series of strongly chitinized hooks, most of which are grouped on right side of cavity with blackened apices directed towards