NORTH OF MEXICO. 281 



\t no verj distant daj this genus and the preceding will have to be united. The 

 only character separating them having proven to be of trifling value among the Asidini. 

 Centrioptera infausta has alreadj afforded a link uniting the forms of the species of both 

 genera 



TRIBE XIV — ASIDINI. 



Mentum large, more or less complel sly hiding the parts above it, supported or not by 

 a a ilar process. Epistom i short, mandibles and labv n i exp ised. Last joint of maxillary 

 palpi triangular and securiform. Antennae eleven-jointed, with the last joint smaller than 

 the preceding. .Middle coxae usually with distinct trochantin. Entercoxal process of all- 

 ium obtuse, not triangular. Legs moderate, tarsi setose but not sulcate beneath. 



The genera of our fauna may be considered as representing two distinct sub-tribes, as 

 follow - : 



Middle coxae not enclosed by the sterna, angulate externally, and with a 



very distinct trochantin. asidi. 



Middle coxae closed by the sterna, rounded, trochantin very small or 



wanting. astroti. 



A third sub-tribe is noticed by Lacordaire, containing the g Machla, differing 



abundantly from either of the above tribes in the presence of grooves on the under surface 

 of the thorax for the reception <>i the antennae. 



SUB-TRIBE I — ASIDI. 



Two genera constitute this tribe in our fauna: 

 Inflexed portion of elytra narrow, composed entirely of epipleura. microschatia. 

 Indexed portion of elytra wide; epipleura 1 very narrow and indistinct, asida. 



In Asida the epipleurae are generally very indistinctlj defined, while in Microschatia 

 the suture is indicated by a well defined ridge forming the elytra! margin. 



MICROSCHATIA, S , 



Microschatia, Sol . i.nn. Soc. Ent. V.. 771. 



Three species compose this genus and are defined as follows: 

 Thorax narrower at base than at middle, and with median basal im- 

 pression ; elytra oval. 

 Elytra with series of coarse puncture-, thorax smooth. punctata. 



Elytra rugose, thorax coarselj and confluently punctured. inaequalis. 



Thorax as broad at base as at middle, sides of elytra parallel in front, 

 humeral angles distinct. 

 Elytra sulcate, thorax smooth. sulcipennis. 



AMKlll. PHI] — Y"l.. XIV. — 71 



