162 PROCEEDmGS OF THE NATIONAL MUSEUM vol. im 



4. Margin on posterior edge of pronotum broadly interrupted medially. (Central 



America) Bolbelasmus (formerly Kolbens) arcuatus Bates 



Margin on posterior edge of pronotum complete 5 



5. Elytron with five striae between suture and humeral umbone; humeral angle of 



elytron not broadly rounded, the margin almost always produced into a 



tubercle at the angle Eucanthus 



Elytron with seven striae between suture and humeral umbone; humeral angle 

 of elytron broadly rounded, the margin never produced into a tubercle at the 

 angle 6 



6. Middle coxae nearly contiguous, intercoxal process less than 0.3 mm. wide and 



linear between coxae Bolbelasmus 



Middle coxae v/ell separated, intercoxal process more than 0.3 mm. wide and 

 never linear 7 



7. Base of elytron margined; pronotum without postapical carina 8 



Base of el3^ron not margined; pronotum with a postapical carina extending 



almost to side margins . . . Bolborhombus (Bolboceras of authors in part) 



8. Apex of tibia of middle and hind legs deeply emarginate on outer side, the angle 



adjacent to spurs appearing almost as a fixed spur; without prosternal 



spine Bradycinetulus 



Apex of tibia of middle and hind legs obliquely truncate, prosternal spine 

 behind anterior coxae transverse, doubly pointed and remote from acutely 

 angled intercoxal piece Bolboccrastcs 



II. Key to genera of North and Central American Geotrupini 



1. Elytra fused, connate, their surfaces roughly granulate; flightless species. 



(Southeastern U. S.) Mycotrupes 



Elytra free, if connate not roughl}^ granulate 2 



2. Eye canthus abruptly angulate anteriorly, clypeus V-shaped, with horn or 



raised longitudinal carina running its length; thorax anteriorly with horn in 

 males, merely slight postmarginal protrusion in the females. (Mexico.) 



Ceratotrupes 



Eye canthus broadly arcuate anteriorly, clypeus usually approximately U- 



shaped, with small median tubercle posteriorly, but no longitudinal carina; 



thorax anteriorly without horn or postmarginal protrusion in either sex . 3 



3. Middle and hind tibiae each with a pronounced transverse apical carina; 



margin of elytron not widel}^ flared. (North and Central America.) 



Geotrupes 



Middle and hind tibiae with only a trace of an external transverse apical carina; 



margin of elytron widely flared. (Florida) Peltotrupes 



LARVAL CHARACTERISTICS 



The larvae of the North American Geotrupinae can be distinguished 

 from the larvae of other North American Scarabaeidae by the following 

 characteristics. 



Antennae 3-segmented, the penultimate segment bearing one or 

 more conical sense organs. Third segment greatly reduced in diameter. 

 Inner and outer lobes of the maxillae entirel}'^ free. Teeth present on 

 maxillary stridulatory area. Hypopharynx with oncyli. Terga of 

 abdominal segments 3 to 7 with two dorsal annulets. Alesothoracic 



