DIAPERINI NORTH OF MEXICO TRIPLEHORN 



363 



North American species of the genus are obviously very closely 

 related as indicated by the structure of the male aedeagus (pi. 4) as 

 well as by the unicolorous, shiny dorsal surface. Of the numerous 

 Neotropical species dissected for genitalic studies, none possessed 

 this type of aedeagus. P. viriditinctum Champion, from Mexico, is 

 the only other new world species which appears to belong to the 

 P. americanum group. This conjecture is based solel}^ on the ex- 

 ternal morphology of the only specimen available for study, one of 

 Champion's cotypes, which is a female. 



It is noteworthy that only two species of this P. americanum group, 

 P. excavatum and P. mexicanum, are found south of the Rio Grande. 



Before any broad generalizations can be offered regarding the 

 origin and phylogeny of the tribe, the world fauna must be reviewed 

 in greater detail, particularly in regard to the genitalia. The re- 

 lationships of the beetles with their host fungi mentioned under the 

 section on biology, when more completely analyzed, will perhaps 

 contribute greatly to our understanding of these interesting but 

 perplexing problems. Any such attempts at this time would of 

 necessity be based on only the most fragmentary evidence and would 

 be highly speculative. 



Checklist of North American Diaperini 



Diaperis Miiller 



maculata Olivier 



californica Blaisdell 



rufipes Horn 



nigronotata Pic 

 Neomida Latreille 



bicornis (Fabricius) 



aeneipennis, new species 



ferruginea (LeConte) 



myllocnema, new species 

 Palemhus Casey 



ocularis Casey 

 Platydema Laporte and BruUe 



excavatum (Say) 



teleops, new species 



cyanescens Laporte and Brull6 



americanum Laporte and Brulle 



mexicanum Champion 



neglectum, new species 



oregonense LeConte 



laevipes Haldeman 



subcostatum Laporte and Brulle 



picilahrum Melsheimer 



ruficorne (Sturm) 



rvficolle Laporte and Brulle 



ellipticum (Fabricius) 



flavipes (Fabricius) 



nigratum (Motsclioulsky) 



erythrocerum Laporte and Brulle 



wandac, new species 



inquilinum Linell 



micans Zimmerman 

 Scaphidema Redtenbacher 



aeneolum (LeConte) 

 Liodema Horn 



laeve (Haldeman) 

 Apsida Lacordaire 



belli Bates 

 Alphitophagus Stephens 



bifasciatus (Say) 

 Pentaphyllus Dejean 



pallidus LeConte 



californicus Horn 



Incertis sedae: Uloporus ovalift Casey 



