ON SOME TEERESTRIAL ISOPODS IN THE UNITED STATES NATIONAL MUSEUM By Hans Lohmander, Of Lund, Stoeden Having devoted much time to the study of the Trichoniscidae of northern Europe, I desired also to know something of the species of this family of terrestrial Isopods that had been found in North America. Through the friendly assistance of Dr. Waldo L. Schmitt, curator of marine invertebrates, a series of specimens was sent to me for study from the United States National Museum. My ex-amination of this collection has given rise to the following article. In the North American collection I have found three species more or less widespread in Europe, Trichords(ym pusillus Brandt, Trichoniscus fygmaeus Sars, and Haplophthalriius danicus Budde-Lund, and two species foreign to Europe, Triehmiiscus papilldcornis Richardson and Brackenrictgia cavernarum Ulrich. It is reasonably certain that at least two of the species first men-tioned, Trichoniscus pygmaeus and HaplopMhalrrms danicus, have been brought to North America from Europe with garden produce, etc. In the greater part of their European ranges these species also bear an obviously synanthropic character and are to be found most frequently in hothouses, gardens, graveyards, etc. With respect to Trichoniscus pusillus it is more difficult to arrive at a definite conclusion. Its presence and distribution in North America is first to be carefully considered. It seems, however, re-motely possible that this species — occurring over the whole of central and northern Europe and being the most common of all the ter-restrial Isopods found in the Scandinavian countries — may also be indigenous in the eastern parts of North America. Trichoniscus papillicornh Richardson, which thus far has been found only in the extreme northern portion of the Pacific Ocean (Bering Island and Cook Inlet) has on a close examination been found not to be a Trichoniscus. It belongs to the family Scyphacidae and is nearly allied to certain species of terrestrial Isopods which No. 2713.— Proceedings U. s. National Museum, Vol. 72, Art. 17 55225—27-1 ^
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