The Male Genitalia of the New Zealand Pterophoridae. By Alfred Philpott, Hon. Research Student in Lepidoptera, Cawthron Institute, Nelson. [Read before the Nelson Philosophical Society, 29th August, 1928; received by Editor, 18th September, 1928; issued separately, 30th November, 1928.] About 20 New Zealand species of this family have been recorded, two or three of which are of doubtful validity. All are endemic except the practically cosmopolitan Stenoptilia zophodactyla Dup.; no endemic genus, however, has been evolved. The most striking characteristics of the male genitalia are the complete absence of all trace of the gnathos and socii, the lateral position on the aedeagus for the entrance of the ductus ejaculatorius (not in Alucita) and the peculiar form of the juxta. Not having as yet studied the other Pyraloid families, I am unable to say if the absence of the gnathos and socii is of any phylogenetic significance, but I note that Petersen (Die Gattung Crambus F. Verhand, 111, Internat. Ento-Kongres. Zurich, p. 405) figures a well-developed gnathos (which he terms the “subscaphium”) in Crambus. The genera Platyptilia and Stenoptilia have long been recognized by systematists as groups which are not separable by definite and unfailing characters. Though the bulk of the species can be assigned to the separate categories without much difficulty there remain a fair number of forms which fit about equally well into either genus. The male genitalia offer no help in this connection; it is not possible to distinguish the structures generically, and one description may be used to cover the united groups. Platyptilia Hübner. Stenoptilia Hübner. (Figs. 1–8.) These genera are practically cosmopolitan. Platyptilia contains by far the greater number of species though Stenoptilia would appear (owing to the absence of the black scales in the fringes of the hindwings) to be the more primitive. The two genera comprise all except four of the known New Zealand Pterophoridae, but only eight species have been available for dissection. Tegumen short, broad, not fused with vinculum; uncus long, narrow, pointed, curved or bent, with short backwardly-directed hairs on upper surface. Aedeagus strongly curved, rather swollen basally, the ductus ejaculatorius entering this swollen portion on the left side; just above this swollen portion is a thumb-like process projecting ventrally and coming into contact with the basal groove of the juxta, while the apical portion of the aedeagus rests between its upper lobes. Juxta forming a curved somewhat funnel-shaped structure at base, with a pair of broad lobes above, and ending in another pair of lobes which are more or less triangular and pointed; both