18 PROC. ENT. SOC, WASH., VOL. 48, NO. 1, JAN., 1946 STUDIES IN THE MELOLONTHINE SCARAB BEETLE GENERA OF THE AMERICAN CONTINENTS. I. REVISION OF THE GENUS ATHLIA. By Lawrence W. Saylor Research Associate, California, Academy of Sciences San Francisco, California This is the first of a projected series of studies in the genera of scarab beetles belonging to the subfamily Melolonthinae. The species are quite plentiful in the Americas and approxi-mately 105 genera and 2,200 supposedly-valid species (550 species from the United States and 1,640 species from Central & South America and the West Indies) have been described to date; hundreds of proposed names now known to be syno-nyms are not taken into consideration in the above count. Numerous undescribed species and several undescribed genera await description in the writer's collection, and it is planned to describe these miscellaneous new species in these papers dis-cussing the generic characters and proper taxonomic position. In no other group of the scarab beetles are the genera so little known and understood, nor as poorly characterized, as in the present subfamily. Moreover, many of the genera are very rarely represented in collections, and at least one-fourth of the known genera are totally unrepresented in United States col-lections, and I have examined the collections of nearly every one of the larger institutions and museums. To illustrate the confused condition, in the Plectris-gvoup of genera, there are at least four other genera in "common" use today that are either directly synonymous with Plectris (when one studies hundreds of species) or must be entirely revaluated and restricted or expanded if we are able to keep and use these names at all. Moser himself, formerly one of the outstanding experts on the group before his death in the 1920's, has described species in Plectris, or Philochlaenia or Rhinaspis, and later decided to move them from one genus to the other for various reasons, and Moser "knew" more species in these "genera" than any previous author. Based on the study of hundreds of Moser's types in the Say-lor Collection (acquired through the courtesy of the world expert on the ruteline scarabs. Dr. Ohaus), it is obvious that Moser's understanding and use of the 'genus' is a little at vari-ance with the commonly accepted use of this category. Many of his genera are well set off, but others (as in the Barytas com-plex) are divided merely on the number of antennal segments, and as any intensive worker on the scarabs knows, this is a highly variable character in many groups; in fact, very many cases are known where a particular specimen has different
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