110 REVISION OF THE ELATEKIDjE 



tional characters, has been made: a Herculean task which might terrify the most adven- 

 turous, hut which the voluminous and widely-scattered memoirs of Mr. Solier have ren- 

 dered still more necessary. 



The scheme of arrangement, into primary divisions, above indicated, is as follows: — 



Subfam. I. EUCNEMIDES. 

 Antennae in sinubus insertae; clypeus antice dilatatus; labrum indistinctuin; abdomen 

 5-articulatum : prosternum antice non vel vix lobatum. 



Div. 1. Mclasides. 

 Antenna? fere distantes; palpi maxillares articulo ultimo ovali acuto. 



Div. 2. Eucnemides (genuini.) 

 Antenna! approximate; palpi maxillares articulo ultimo magno, dilatato; ungues non 

 pectinati. 



Div. 3. Ccrophytides. 



Antenna; valde approximate; palpi maxillares articulo ultimo magno dilatato; ungues 

 pectinati. 



Subfam. II. E L A T E R I D E S . 



Antenna; in foveis lateralibus, sub fronte inserts; clypeus antice non dilatatus. 



Div. 4. Elaterides (gcmiini.) 

 Mandibular parvae, labrum distinctum; abdomen 5-articulatum; palpi labiales breves, 

 maxillares articulo ultimo maiore prsecipue dilatato: prosternum prsecipue lobatum. 



Div. 5. Ccbrionidcs. 

 Mandibular elongate, porrectsej labrum indistinctum ; prosternum non lobatum; abdo- 

 men stepe G-articulatum; palpi omnes longiusculi, articulo ultimo cylindrico, truncato. 



N. B. — The Catalogue of the described Colcoptcra of the United States, by Dr. Mel- 

 sheimer, being intended merely as an index to descriptions, has not been quoted in this 

 essay for any changes in nomenclature there introduced, as if retained, without special 

 reason and reference, they were intended as mere suggestions, and not as contributions 

 to science. 



Div. 1. MELASIDES. 



I have constructed this group from two genera, Mclasis and Tharops, which differ from 

 Eucnemis by the following characters: — 



The head is large, so that the eyes, which arc small, become entirely disengaged from 

 the thorax; the antenna) are inserted in emarginations of the clypeus, but arc more widely 

 separated at the base than in Eucnemides: the clypeus is emarginate anteriorly in one 

 genus, but the labrum is indistinct: the last joint of the maxillary palpi is oval and acute, 

 very little larger than the preceding joint: the prothorax beneath is truncate, the suture 



