LISTEOCHELTJS. 171 



c? . Pygidium gibbosum, politum, glabrum, dispersissime punctulatum. Venter medio concavus et canaliculatus, 

 parcissime setosus ; segmento 6° brevi, fere lsevi. Ungues elongati, omnes (prope apicern excepto) breviter 

 pectinati. Pectus dense fulvo-villosum. Antennarum clava elongata, articulis 2°-6 m conjunctis sequalis. 



$ . Pygidium fere planum, politum, glabrum, dispersissime punctulatum. Yenter convexus, lsevis ; segmento 6° 

 apice medio profunde inciso. Ungues medio breviter dentati, deinde usque ad basin paull dilatati et 

 minute denticulati. 



§ . Variat unguibus pedum 4 anteriorum medio dentatis, 2 posteriorum edentatis et baud conspicue denticulatis ; 

 vel omnibus edentatis. 



Long. 8-10 millim. 



Edb. Mexico, Toluca {Edge). 

 Numerous examples. 



4. Listrochelus praBsidii. (Tab. X. fig. 5, <s .) 



Elongates, fere cylindricus, castaneus, thorace lsetius rufo-castaneo, polito, elytris fulvo-testaeeis, palpis, antennis 

 pedibusque fulvo-rufls, nitidis ; clypeo transverso, antice obtusissime rotundato, parum sinuato, mediocriter 

 reflexo, dense discrete punctato, sutura frontali acute impressa flexuosa, fronte sparsim punctata, vertice 

 obtuso ; thorace medio valde dilatato, antice et postice angustato, angulis anticis oblique truncatis, posticis 

 obtusis, supra disperse punctato ; elytris parum dense punctulatis, interstitio suturali vix elevato, sub- 

 punctulato. 



<5 . Pygidium gibbosum, medio dense punctulatum et fulvo-setiferum, apice politum, sparsissime punctulatum. 

 Venter lateraliter argenteo-pruinosus, medio nitidus, depressus, aspere setifero-granulatus ; segmentum 5 m 

 postice profunde sinuatum, 6 m medio elongatum, concavum, granulatum, et breviter canaliculatum. Pectus 

 cinereo-fulvo villosum. Ungues omnes subtus sequaliter bipectinati. 



2 . Pygidium basi planum, prope medium subito convexum ibique profundissime sulcatum. Venter medio 

 glaber ; segmentum 5 m apice integrum, 6 m convexum, punctatum. Ungues supra medium valde dentati, 

 deinde usque ad basin serrulati. 



Long. 18 millim. 



Hab. Mexico, Presidio (Forrer). 



Two male and two female examples. Apparently closely allied to L. disparilis, 

 Horn, from Arizona and New Mexico ; but differing sufficiently in the sculpture and 

 clothing of the pygidium, form of the ventral segments, and general colour. The con- 

 vexity of the lower part of the pygidium in the female may be described, in other 

 words, as two elongate polished callosities separated at the median line by a deep and 

 straight furrow. 



5. Listrochelus scuticeps. 



Anguste oblongo-ovatus, fulvo-testaceus, thorace femoribusque rufo-testaceis, nitidis, elytris leviter pruinosis, 

 subopacis ; fronte et clypeo (piano declivi) dense subalveolato-punctatis, occipite transversim sulcato, lsevi, 

 clypeo longiusculo semiovato, antice obtuso, margine reflexo, antice -paullo sinuato; thorace paullo post 

 medium valde dilatato, angulis obtusis, sat dense sed discrete punctato, linea dorsali lsevi ; elytris ruguloso- 

 coriaceis haud distincte punctulatis. 



S . Pygidium prope apicem gibbosum, nitidum, sat distanter piloso-punctatum. Venter medio concavus, politus, 

 fere lams ; segmento 5° apice canaliculate, 6° subconvexo, grosse punctato, medio acute canaliculate. 

 Ungues elongati, apice excepto pectinati. Antennarum clava elongata, gracilis, articulis 2°-7 m conjunctis 

 parum brevior. 



$ Pygidium fere planum, apice rotundatum, disperse piloso-punctatum. Venter medio fere lsevis ; segmento 6° 



ZZ2 



