214 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



Bolboceras simi (Wallis) was carefully described by Ritcher (1947, pp. 

 13, 14). The larvae of Bolboceras darlingtoni and liebecki are subse- 

 quently briefly described for the first time by listing only the structures 

 which differ from Ritcher's description of B. simi. 



Generic larval characteristics exhibited are: Antennae (pi. 6, fig. 3) 

 with one conical sense organ on penultimate segment; first segment 

 longer than second, which is longer than the third; body not humped 

 (pi. 12, fig. 1); anal opening transverse (pi. 6, fig. 10) with lower anal 

 lobe unpaired; pro thoracic legs smaller than others, which are similar 

 in size. Legs 2-segmented, lacking claws. 



Members of this genus are found largely in the eastern United States 

 and in southeastern Canada, with the exceptions of one species occur- 

 ring in the western United States and one in Europe. 



Biological information on the genus is rather sparse, almost all of 

 the information previously available having been accumulated by 

 Sim (1930). In addition to this published work, Wallis (1928) 

 quotes a number of statements on biology made by Sim in personal 

 correspondence . 



Key to the known larvae of the North American species of Bolboceras 



1. Anterior frontal setae absent; glossa not emarginate; hypopharynx symmetrical, 



pternotorma absent simi 



Anterior frontal setae present; glossa vaguely emarginate; hypopharynx (pi. 6, 

 figs. 8, 11) somewhat asymmetrical, epipharyngeal pternotorma indicated . 2 



2. Epipharynx (pi. 6, fig. 12) with a small posterior epitorma; small pternotorma 



elongate liebecki 



Epipharynx (pi. 6, fig. 9) with a large posterior epitorma; small pternotorma 

 bulblike darlingtoni 



Bolboceras obesus (LeConte) 



Odontaeus obesus LeConte, 1859, pp. 282-283 (type, male, LeConte collection, 

 MCZ).— Horn, 1870, p. 47.— Wallis, 1928, p. 127. 



Bolboceras obesus (LeConte) is the only species of this genus occur- 

 ring in the western United States where, from the number of specimens 

 examined, in many places it seems to be rather common. 



Specimens have been collected in almost every month of the year, 

 but adult activity appeared from the data to approach its peak m 

 spring and early summer. While the adult habits appeared similar to 

 the eastern species, little biological information has been amassed. 

 Adults have been occasionally noted coming to light. Linsley and 

 Michener (1943, p. 79) made the following observations on obesus in 

 the vicinity of Mount Lassen, Calif.: "Several hundred pupae and a 

 few larvae of this species were excavated from the sandy soil of an old 

 road bed in the midst of a manzanita chute on June 16 [1941]. One 

 adult female was found at this time. The pupal cells averaged 8X7 

 X15 mm., and were found at a depth of from 3 to 6 inches below the 



