The New Zealand Species of Iais (Crustacea Isopoda)* Contribution No. 149, from the Allan Hancock Foundation. By D. E. Hurley [Received by Editor March 1, 1955.] Abstract Iais californica (Richardson) is recorded from New Zealand and considered identical with Chilton's Iais pubescens var. longistylis. Other New Zealand records of Iais are briefly discussed and host associations noted. Introduction and Acknowledgments Iais is a genus of small asellote isopods found associated with certain sphaeromid isopods, usually on the ventral surface of the larger animal, between the peraeopods and on the pleopods. The exact relationship of Iais to its host and its dependence on the Sphaeromid is still uncertain Chilton (1892, 1909) claims to have found specimens of Iais living freely on seaweed and under stones on beaches and at the mouths of freshwater streams. Menzies and Barnard (1951), in their recent revision of the genus, suggest that these reports may be in error. The specimens discussed below came from sphaeromid isopods collected by Mr. E. M. Sladden, Engineer for the Hutt Valley River Board, and received through the courtesy of Professor L. R. Richardson, of Victoria University College, Wellington. I am extremely grateful to Captain Allan Hancock for the use of facilities at the Hancock Foundation, to Dr. John S. Garth of the Foundation; and to Dr. J. Laurens Barnard, from whom I have had much assistance during the preparation of this paper. This work has been carried out during the tenure of a Fulbright Research Scholarship. Genus Iais Bovallius, 1887. Menzies and Barnard, 1951: 137. “Eyes present, each consisting of two facets. First antenna with six articles. Second antenna without a scale. Epimeral plates visible in dorsal view on all peraeonal somites. Lateral margins of peraeonal somites not deeply incised, borders setiferous. Apex of male first pleopod not widely expanded laterally. Third pleopod without pluniose setae on endopod. Dactyls of first peraeopods with two claws; those of others with three claws. First two articles of maxillipedal palp as wide as endite; apical three articles much narrower than endite. Mandible with a triarticulate palp and with an evident, elongate, apically blunt molar process.' Iais californica (Richardson). Figs. 1-13. Iais californica (Richardson). Menzies and Barnard, 1951: 141-143, Pls. 44-45. Iais pubescens (Dana) var. longistylis Chilton. Chilton, 1912: 132, 134. Iais singaporensis Menzies and Barnard, 1951: 144, Pls. 46-50. “First antenna about one-sixth the length of the body and nearly three-tenths as long as the second antenna Second antenna about six-tenths the length of the body; flagellum with twenty-four articles. Maxilliped with three coupling