NORTH AMERICAN GEOTRUPESTAE — HOWDEN 299 



and in the spring larvae and adults were taken from the same buiTow. 

 While the larval food appeared to be the finely divided surface humus, 

 its use was not definitely established. In one way Eucanthus differed 

 markedly from Bolboceras — the adults were never seen to feed, nor 

 were they ever found near anything that could seemingly be used for 

 food. None was taken by any chemical attractant or by fermenting 

 malt, but specimens did come freely to fight. In these last respects, 

 the habits of Eucanthus were the same as those of Brady cinetulus, 

 Bolbocerastes, and Bolhorhomhus. The species in all of these genera 

 burrow strongly, but there is a dearth of information concerning their 

 habits. 



The biology of only one other genus (Bolbocerosoma) in the Bolbo- 

 ceratini is even partially known. One species, farctum, has had its 

 biology partiaUy described for the first time in this paper. From 

 the small amount of information derived from the single larva, the 

 food is similar to that used by Bolboceras and Eucanthus, i. e., finely 

 divided surface humus packed into a burrow. The larva apparently 

 pupates at one end of its food ceU, and in this respect it differed from 

 Bolboceras darlingtoni. Also, the larval burrow was deeper and less 

 tortuous than that of darlingtoni. The burrow of farctum is dia- 

 grammed in plate 10, figure 3. The dimensions of a typical burrow 

 of Bolbocerosoma are discussed at some length by Bryson (1939, p. 

 249). While the larval development was fully as rapid as in Bolbo- 

 ceras or Eucanthus, taking about two months, the adults were not 

 found associated with the larva as they sometimes were in the cases 

 of Bolboceras and Eucanthus. 



From the above information concerning a few diverse genera in the 

 Bolboceratini, one can only conclude that some of the adults may feed 

 on decaying or fermenting vegetable matter. They are, as a group, 

 strong burrowers, nocturnal in their activity, often coming to light. 

 In the few cases where the larvae are known, finely divided black 

 surface humus was provided by the adults for the larval food. Also, 

 rapid larval development and a long period of adult activity may at 

 present be considered a characteristic of the tribe. 



BIOLOGY OF THE GEOTRUPINI 



The members of the remaining tribe, the Geotrupini, have been 

 subjected to more biological investigation than the other members of 

 the subfamily. This is largely due to two causes ; first, the tribe is well 

 represented in the Northern Hemisphere, and, secondly, many of ^the 

 species can be fairly easily reared in cages. Most of the work has 

 been done in Europe, and, because of the rather voluminous literature 

 and repetition of observations on many species, only the very briefest 

 of simamaries is given here. Much of this information can be found 



