'4 ^3 FIELDIANA ZOOLOGY Published by CHICAGO NATURAL HISTORY MUSEUM Volume 44 November 15, 1961 No. 2 Two New Genera of Feather -Wing Beetles t From the Eastern United States (Coleoptera: Ptiliidae) Henry S. Dybas Associate Curator, Division op Insects The feather-wing beetles of the subfamily Nanosellinae, to which the two new genera belong, are the smallest known beetles (Barber, 1924) . The Nanosellinae in general live in the spore tubes of shelf fungi of the family Polyporaceae (Barber, 1924; Dybas, 1956; and extensive unpublished data). In this respect, the two new genera described in the present paper are atypical. Hydnosella glohitheca, new gen. and sp,, has been found only on the under surface of woody shelf fungi of the related family Hydnaceae in Indiana. It appears to be narrowly host-restricted to Steccherinum (Hydnum) ochraceum (Ft.) S. F. Gray. The other new genus, Suterella, has been collected in forest floor litter in Rhode Island, Pennsylvania, Tennessee, and Georgia. It presumably feeds on fungus spores as do other Nano-sellinae, but its occurrence in the forest floor and the reduced and attenuated head suggest some unusual feeding relation. Two well-defined groups comprise the Nanosellinae. In one group, illustrated among described genera by Nanosella {=Mycophagus sens. Barber, 1924), Porophila, and Cylindrosella, the median ele-vation of the mesosternum is typically shaped like an arrow-or spear-head, and the apex is directed posteriorly between the mesocoxae and usually overlaps the metasternum as a thin, barely detectable, laminate process. In the other group, represented by Throscoptilium and a number of undescribed genera, the apparent apex of the meso-sternal elevation is anterior and the broader posterior portion over-laps the mesocoxae and unites with the metasternum. It may be shaped like a flattened keel that is narrowed in front or broad and Library of Congress Catalog Card Number: 61-18696 No. 937 11 THE UmiJI GF THE FEB 15 1362 natural
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