NORTH OF MEXICO. 



281 



At no very distant day 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. 

 Ccntrioptera infausta has already afforded a link uniting the forms of the species of both 



TRIBE XIV — ASIDINI. 



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

 a gular process. Epistoma short, mandibles and labrum exposed. Last joint of maxillary 

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

 the preceding. Middle coxrc usually with distinct trochantin. Intercoxal process of ab- 

 men 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 

 follows : 



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



very distinct trochantin. ASIDI. 



Middle coxa? closed by the sterna, rounded, trochantin very small or 



wanting. ASTEOTI. 



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

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

 of the thorax for the reception of the antennae. 



SUB-TRIBE I ASIDI. 



Two genera constitute this tribe in our fauna : 



Infiexed portion of elytra, narrow, composed entirely of epipleura. MICROSCHATIA. 



Inflexcd portion of elytra wide; epipleura) very narrow and indistinct. ASIDA. 

 In Asida, the epiplcuroc are generally very indistinctly defined, while in Microschatia 

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



MICROSCHATIA, Sol. 

 Miorosohatia, Sol., Aim. Soc. Ent. V., 774. 



Three species compose this genus and arc defined as follows: 

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

 pression; elytra oval. 

 Elytra with series of coarse punctures, thorax smooth. punctata. 



Elytra rugose, thorax coarsely and confluently punctured. insequalis. 



'['borax as broad at base as at middle, sides of elytra parallel in front, 

 humeral angles distinct. 

 Elytra sulcate, thorax smooth. sulcipcnnis. 



AMElir. I'll II, (),S(>. SOC. — VOL. XIV. — 11 



