106 [^Piil. 



ON TWO NEW SPECIES OF MEXICAN RISTERIDM. 

 BY G. LEWIS, F.L.S. 



Mr. Julius Flohr has kiudly sent me two new species recently 

 discovered by himself in Mexico ; one of them pertains to a new 

 genus, and was found within the precincts of an ants' nest, the other 

 is a true Hister, and one bearing remarkable characters. 



HiSTER LATISTEIUS, 11. Sp. 

 Sreviter avails, convexiusculus, niger nitldus ; f route tenuissime punctu- 

 lata, stria suhintegra ; fronoto stria externa Integra interna hasi ahbreviata ; 

 elytris striis 1 — 3 integris, 4 basi ahbreviata, 5 — 6 dimidiata ; ijygidio pro- 

 pygidioque Icevibus ; prosterno hand striata ; tibiis anticis emarginatis. 



Lang., 4f mill. 

 Hah. : Tepic. 



Head with extremely fine and scattered punctuation, frontal stria semicircular, 

 and scarcely meeting anteriorly ; thorax transverse, impunctate, outer stria complete 

 and looped behind the anterior angle, inner stria much abbreviated before the base, 

 but continues anteriorly behind the neck unbroken and slightly crenate ; the elytra 

 have broad but not deep striae, each of which is feebly crenate on either edge ; 1 — 3 

 complete, 4th a little abbreviated at the base, 5th and 6th, apical, nearly equal in 

 length, and terminating just beyond the middle. Tlie three inner striae are less 

 broad than the others. The pygidium and propygidium are nearly smooth, being 

 more feebly punctate than those in S. coenosus, Er. The prosternum is without striae, 

 all the sternal plates are smooth, mesosternal stria complete. The anterior tibiaj are 

 peculiar. At their apex there is a large tooth, which is minutely tridentate at its 

 apex, and between it and two or three small teeth at the bases, the outer edge is 

 conspicuously emarginate. 



The species may be placed near H coenosus, Er. 



Trichokeninus, n. gen. 



Orbicularis, parum convexus setosus ; caput retractum. Mandibulis 

 robustis, in incdiis valde unidentatis ; antennis brevibus, sub front e maV' 

 (jine insertis, clavd articulo unico ovato et ccBteris sensim incressatis, 

 funiculo magna, Prosternum modice carinatum, bistriatum basi inciso ; 

 mesosternum marginatum utrinque profunde sinuatum in medio acu- 

 minatum ; pygidium parum convexum. Femora et tibice dilatatce. 



This genus comes very near to Reninus, Lewis, 1889 (Hetiia, 

 1885), but the species cannot be placed in it. It is sparsely covered 

 with setae ; the legs are less dilated with the angle on the outer edge 

 much nearer the base. The dorsal sculpture also is very different, 

 and the prosternum carinate. The genus also appears to be similar 

 to TJlkenus, Horn, but in Horn's genus the mesosternum is semi- 

 circular in front. The setae seem liable to be rubbed off, but I think 

 in a fresh example each puncture would bear one. 



