164 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



coxae with a tooth-like elevation, intermediate coxae very narrowly 

 separated, nearly contiguous." 



Other useful characteristics are: Yellow or red-brown color, dorsally 

 with black markings, lateral pronotal carinae no wider than head, at 

 least a few deep coarse median punctures on pronotum, elytral base 

 not margined. 



Malf Genitalia: The genital capsule of the male is the most 

 conspicuous part of the genital structures. The genitalia itself is 

 rather simple, with symmetrical pointed parameres and a central 

 spiculate aedeagus. Characteristics useful in differentiating various 

 species were found mainly in the size and shape of the lateral lobes of 

 genital capsule. The capsule readily separates the genus into the 

 following species groups: 



(A) Capsule large, heavily sclerotized, lateral lobes elongately (over twice as long 



as wide) triangular, narrowly separated at tip, lobate basally. 



fare turn, confusum 



(B) Capsule slightly smaller and less sclerotized, lateral lobes with bluntly angu- 



late tips, widely separated, not lobate basally . . tumefactum, bruneri 



(C) Capsule small with lateral lobes deflexed at tips to form hooks . hamatum 



(D) Capsule small, moderately sclerotized, lateral lobes with tips blunt and 



broadly rounded All remaining species 



In the genus Bolbocerosoma intraspecific variation, particularly 

 in males, is very evident, expressing itself in the size of the tubercle on 

 the eye canthus, the tubercle at the midline of the clypeus, the horn of 

 the vertex, and the development of the pronotal modification. Gen- 

 erally, the modifications of the head and pronotum of the males are 

 well developed, only occasionally being very small, with the pronotal 

 modification quite similar to those of the female. In the females 

 variation is much less noticeable. 



Descriptions have been based, whenever possible, on well-developed 

 individuals. Variations in size, color pattern, and punctation occur 

 and are noted for each species whenever variation is evident. 



Known larvae in this genus may be distinguished from related 

 genera by the following characteristics: Antennae 3-segmented, 

 penultimate segment with two conical sense organs, galea emarginate, 

 legs 4-segmented with pronounced claws, metathoracic legs not re- 

 duced, and abdomen not enlarged. 



Key to the North and Central American species of Bolbocerosoma 



1, Elytron with seven deep and strongly punctured striae between suture and 



humeral umbone 2 



Elytron with five deep and strongly punctured striae between suture and 

 humeral umbone, the second and fifth striae feeble or obsolete 3 



2. Pronotum never with a black median spot or stripe, distal black area of 



elytron confluent with the black sutural stripe. 



bruneri Dawson and McCoUoch 



