290 PROCEEDINGS OF THE NATIONAL MUSEUM vol. i04 



coupled with distributional data, should be sufficient for identification. 



The larva of Mycotrupes gaigei (the only species in which the larva 

 is known) can be separated from any of the known larvae of Geotrupes 

 by the shape of the endoskeletal figure, which lacks the sharp lateral 

 expansions and abrupt angles found in the larvae of Geotrupes. 



The discovery of the larva of Mycotrupes was made following the 

 completion of the plates and descriptions for the present work. 

 Since a discussion on biology and a larval description is given in the 

 paper by Olson, Hubbell, and Howden (1954), only a brief account 

 of my observations is included here. 



All of the known species in the genus range in areas of deep sand 

 from southern peninsular Florida northward to central South Carolina, 

 and from the coast near Brunswick, Ga., westward to southwestern 

 Georgia. 



Mycotrupes retusus (LeConte) 



Geotrupes retusus LeConte, 1866, pp. 381-382 (type, male, LeConte collection, 



MCZ).— Horn, 1868, p. 314.— Blanchard, 1888, p. 109. 

 Mycotrupes retusus (LeConte) Olson and Hubbell, in Olson, Hubbell, and Howden, 



1954, pt. 1, pp. 28-33. 

 tGeotrupes aeneus Felsche, 1909, pp. 759-765. 



This species, long incorrectly considered a synonym of lethroides, 

 can be distinguished by the following characteristics: Clypeus rounded 

 anteriorly and laterally; median pronotal tubercle often absent in 

 both sexes, when present indicated in the male by a linear triangular 

 callus confluent with the margin, and in the female by a small sub- 

 triangular expansion of the median anterior pronotal margin; dorsal 

 cii'cular granules generally evenly spaced; lack of elytral striae; and 

 the inwardly produced hatchet-shaped tip of the extended left ventral 

 portion of the phallobase of the male genitalia (pi. 5, figs. 5, 7). 



Adults of retusus have been found active during the spring and fall 

 months. They have been collected only in areas of deep sand where 

 they have been noted feeding on fungi and dung. 



In September 1951 P. O. Ritcher and I collected several specimens 

 at White Pond, S. C, in burrows ranging from 17 to 36 inches deep. 

 The weather had been dry and no surface activity was noted. The 

 bm^rows were found by scraping away pine litter under thick stands 

 of long-leaf pines, exposing the traces of the old push-ups marking the 

 burrow entrance. 



No signs of any food or larval cells were found. Several of the 

 beetles were kept alive and later placed in a rearing cage at Raleigh, 

 but, while both dung and fungi were supplied and the adults remained 

 alive for almost a year, no larval cells were produced. At no time 

 were males and females found in the same burrows. 



