A NEW GENUS AND SPECIES OF OSMYLIDAE (NEUROPTERA) FROM CHILE AND ARGENTINA, WITH A DISCUSSION OF PLANIPENNIAN GENI-TALIC HOMOLOGIES PHILLIP A. ADAMS Department of Biology and Peabody Museum of Natural History, Yale University* Abstract Phymatosmylus, a new genus of Stenosmylinae, is proposed for the new species Phymatosmylus caprorum. The genus is mor-phologically primitive in the position of the medial fork of the forewing, and in the partially free eighth abdominal tergite of the male. Osmylid female genitalia are prepared for examination by the customary clearing in KOH and staining in chlorazol black E, but removal of the internal structures from the abdomen, following cutting around the genital opening, makes details more visible than when examined in situ, as previously. The male gonarcus-mediuncus complex of Planipennia is probably derived from fused parameres, as in some Sialodea, and the articulation of the gono-coxites has shifted from the ninth tergite to the ends of the gonarcus. ^Present address: Department of Biology, California State College, Ful-lerton, California 92631. POSlllLA 141: 11 p. 26 DECEMBER 1969.