TERRESTRIAL ISOPODS COLLECTED IN COSTA RICA BY J. F. TRISTAN, WITH DESCRIPTIONS OF A NEW GENUS AND SPECIES. By Harriet Richardson, Collaborator, Division of Marine Invertebrates, U. S. National Museum. Among some isopods recently sent to the U. S. National Museum from Costa Rica by Prof. J. F. Tristan were twelve specimens repre-senting a species belonging to a new genus of Armadillididse. Two previously known species were also found. COXOPODIAS, new genus. Body oval, convex. Eyes distinct, composite. Second antennsB with a flagellum composed of two articles, the second being twice as long as the first. Coxopodite of first thoracic segment extending the entire length of the lateral margin, cleft posteriorly, and separated from the seg-ment by a longitudinal furrow; there is also a slight furrow on the dorsal surface of the segment close to the lateral margin. Coxopo-dites are present on the second and third segments of the thorax on the underside in the form of small, but conspicuous tooth-like processes. Terminal abdominal segment triangular, with the apex acutely produced. Basal article of the uropoda large, obliquely quadrangular; inner branch about as long as the basal article; outer branch minute, inserted about the middle of the dorsal surface of the basal article. This genus is close to Ethelum Budde-Lund, but differs in the possession of distinct coxopodites on the second and third thoracic segments, in the position of the outer branch of the uropoda, and in the possession of only two plumose processes on the inner lobe of the first maxillge. Genotype. — Coxopodias tristani, new species. Proceedings U. S. National Museum, Vol. 39— No. 1775. 93
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