TENEBRIONIDAE. 221 



the 11th joint smaller than the 10th ; elytra embracing widely 

 the flanks of the abdomen (except in Microschatia) ; epipleurse 

 indistinct, middle coxas with distinct trochantin, side pieces of 

 mesothorax scarcely reaching the cavities ; metasternum very 

 short, with the episterna wide, and epimera not visible ; hind 

 coxae moderately separated ; intercoxal process of abdomen ob- 

 tuse ; 4th and 5th ventral segments somewhat prolonged behind 

 at the sides. Legs moderate, tibial spurs distinct ; tarsi setose, 

 but not sulcate beneath. Front transversely impressed in all the 

 species known to me. 



The shortness of the middle of the front, and the exposed base 

 of the mandibles give a somewhat trilubed anterior outline, thus 

 recalling for the last time, though feebly, the form seen in some of 

 the earlier tribes of the family ; the large size of the mentura 

 is another reminiscence of the tribes alluded to, and this affinity 

 is still more strongly indicated in the foreign genus Machla, 

 which, while placed by Lacordaire in the present tribe, is remark- 

 able for having the middle coxas without trochantin and entirely 

 inclosed by the sterna. Instances like the one here given show 

 the impossibility of exhibiting even the most important affinities 

 in a linear arrangement of a family constituted, like the present, 

 of a very large number of tribes of equal value. 



Our genera are : — 



Mentum filling the gular cavity ; 

 Last joint of maxillary palpi moderate; mentum and mandibles approxi- 

 mate, leaving room only for the palpi ; 

 Infiexed portion of elytra narrow. Microschatia. 



Inflexed portion elytra wide ; 



Prosternum prominent, ant. tibiae with the outer angle prolonged. 



Astrotus. 

 Prosternum not prominent ; anterior tibiae truncate. Ologlyptus. 

 Last joint of maxillary palpi very large ; mentum and mandibles sepa- 

 rated by a wide space. Pelecyphorus. 

 Mentum inserted upon a broad peduncle, lateral fissures distinct ; last joint 

 of maxillary palpi very large ; 



Posterior angles of thorax distinct. Asida. 



Posterior angles of thorax obtuse or rounded. Euschides. 



The last two genera do not seem to be separated by any distinct 

 characters : by combining them Asida would become protean in 

 form like Pelecyphorus and Eleodes. 



The genera Microschatia, Pelecyphorus, and Euschides, occur 

 from Kansas to the Pacific coast ; Astrotus is found in Texas ; 



