1856.] 23 



Middle and Southern States. Of^the same form as the precedinoj, but only 

 one-third the size, with the thorax less punctured, and the alternate striie of the 

 elytra arranged in pairs and composed of smaller punctures than in A. hydro- 

 picus. The sexual differences are as in H. hydropicus. 



II. Thorax at the apex submucronate and slightly foveate, 



6. A. c 1 u n a 1 i s, oblongus, convexus, piceo-castaneus, postice parum dilatatus, 

 capite dense rugose punctato, tenuissime marginato, clypeo ad apicem rotundato 

 submucronato, mox pone apicem linea valde elevata bidentata armato, sutura 

 frontali distincta emarginata, medio tuberculo parvo notata, thorace lateribus 

 valde rotundatis, subtilius punctato, disco versus basin sublaevi, ante apicem 

 fovea parva punctata notato, et in apicem brevissime mucronato, elytris punc- 

 tato-striatis, punctis externis minoribus confusis, propygidio subtilius punctato, 

 ad apicem laevi, pygidio lasvigato modice convexo; abdominis segmentis singulo 

 serie transversa grosse punctato, ultimo tenuiter marginato, (maxillarum galea 

 bidentata.) Long. -95. 



One specimen found by Dr. Thos. H. Webb, of the Boundary Commission, and 

 probably in the valley of the Gila. This species differs so much from the other 

 species of the genus, that it can hardly be associated with them ; I have, how- 

 ever, failed to discover any better place for it, and do not desire at present to 

 increase the number of genera. Although the propygidium is somewhat rough 

 with punctures, I do not perceive any transverse rugae, such as indicate the 

 organs of stridulation in other genera. The hind tibiae are thicker than usual, 

 and the transverse crest at the middle is prolonged externally into an acute tooth ; 

 it does not, however, agree with any of the genera of Pimelopides described by 

 Lacordaire, and seems rather to belong to the division Pentodontides. 



PoLYMCEcHua Lec. 



Clypeus trilobatus, lobis rotundatis, margine fortiter reflexo, ad apicem denti- 

 bus duobus parvis erectis armato, fronte utrinque transversim carinata, carinig 

 margine adnexis ; oculi valde incisi ; mandibulse extrorsum baud dentatse, ad 

 apicem acutae et sursum productaj ; palpi articulo ultimo subcylindrico; (max- 

 illge baud vifse ;) antennae 10-articulatae, clava triphylla, feminje reliqua parte 

 paulo, maris sesqui longiore ; in hoc sexu articulis funiculi externis crassioribus 

 compressis. Prosternum pone coxas hand prominulum. Pedes breves, crassi, 

 tibiae femoribus baud longiores, anticfe ultra medium tridentatse, dentibus ap- 

 proximatis ; intermedise et posticte ultra medium extrorsum emarginatiB et uni- 

 coronata^ ; ad apicem vix ciliatas, angulo externo paulo producto; tarsi tibiis 

 baud longiores, articulis 1 4 asqualibus parce setosis, posteriores articulo Imo 

 hand elevato, 4to vero subtus longe acuminato ; 5to omnium longiore, unguiculis 

 anticis sexus utriusqae simplicibus, posterioribus feminre simplicibus, maris ex- 

 ternis ad medium fortiter dentatis, dente ungue ipso vix breviore. Podex biar- 

 ticulatus nudus. 



A very remarkable genus of regularly oblong oval form, and not furnished 

 with stridulating organs. Its characters approach those of Pachylus, from which, 

 however, it is quite distinct. Professor Lacordaire, to whom I sent a specimen 

 submitted it to a careful examination, and from his letter I translate the follow- 

 ing extract, convinced that the opinion of my most learned friend, who has 

 examined aearly all the genera of this family, will be of more service to the stu- 

 dent than any thing I could say : " The Lamellicorn which you have sent is 

 very remarkable, but there can be no doubt regarding its place in the entomo- 

 logical series. It is a genuine Dynastide, as is proved by the last abdominal stig- 

 mata diverging strongly, and by the form of the mentum, the mandibles and the 

 clypeus ; but it is related to the Melolonthides by the form of the head, the eyes, 

 the antenuiie and the tarsi. Its facies is at once that of certain species of both 

 groups. In short, it is a completely new form, intermediate between the two 

 groups mentioned, and you can without fear found upon it a new genus, 



