414 PROCEEDINGS OF THE NATIONAL MUSEUM vol. i04 



new. Two formerly accepted species, P. aegialioides Haldeman and 

 P. shermani Cartwright, were found to be synonyms of other species 

 and one, P. amhiguus Fall, is removed from Psammodius. Psammodius 

 desertus Van Dyke was removed to the genus Xeropsammoheus by 

 Saylor in 1937 (Bull. Southern California Acad. Sci., vol. 36, p. 36); 

 Psammodius grundeli Van Dyke was removed to Pleurophortis by the 

 writer in 1948 (Trans. Amer. Ent. Soc, vol. 74, p. 138); and Psam- 

 modius schwarzi Linell was removed to Ataenius by Brown in 1928 

 (Canadian Ent., vol. 60, p. 307). 



The genus Xeropsammobeus , erected by Saylor for the species 

 Psammodius desertus Van Dyke and to which I now add Psammohius 

 amhiguus Fall, only superficially resembles Psammodius. Xeropsam- 

 mobeus should be placed in the tribe Aphodiina because the head is 

 not strongly bent downward but lies nearly horizontally as in typical 

 Aphodius: the clypeus is punctate-rugose, not granulate; the pygidium 

 is simple, not grooved basally; and the tibiae bear strong transverse 

 ridges. It should be noted, however, that in Xeropsammobeus the 

 posterior femurs are much wider than the middle femurs and that the 

 middle and hind tibiae are strongly widened to a very noticeably 

 oblique apex. The transverse tibial ridges are also strongly oblique. 

 A paratype of X. desertus (Van Dyke) and the holotype of X. amhiguus 

 (Fall) were examined in the present study. 



I have examined type material (holotype, cotype, or paratype) of 

 all Psammodius described from the Western Hemisphere except 

 cruentus Harold and interruptus Say. Type material of the European 

 species, P. laevipennis A. Costa, basalis (Mulsant and Rey), and sulci- 

 collis (Illiger) were not available, but Eiu-opean specimens were 

 studied. Aphodius clypeatus Say, sometimes placed in Psammodius, 

 is omitted since it is impossible to place the species by the original 

 description alone. 



Measurements in millimeters were made with a Spencer stereo- 

 scopic microscope equipped with an ocular micrometer. Width is 

 the greatest width. Length is measured along the midline. Length 

 of the elytra is measured from the apex along the suture to a perpen- 

 dicular base line touching the anterior margins of the humeri. Where 

 long series of specimens were available, measurements were taken 

 from an average individual to represent the relative lengths. 



Specimens of Psammodius in the U. S. National Museum collection 

 were so few the present study would have been impracticable without 

 the generous cooperation and loan of specimens from other museum 

 and private collections. I am grateful for having had the oppor- 

 tunity to study this material and thank the following who loaned 

 museum specimens: G. J. Arrow and E. B. Britton, British Museum 

 (Natural History) ; W. J. Brown, Canadian Department of Agricul- 

 ture; H. Freude, Zoologische SammJung des Bayerischen Staats, 



