AMERICAN COLEOPTERA. 127 



In both genera the ocellate punctures which are usually observed 

 near the margin of the elytra in Carabidfe are absent, but are present 

 in other genera of the tribe. I have observed also that they are absent 

 in Apotomus, a genus not related to the present tribe. 



Tribe XVII.— Siagonini. 



Antenn* slender, arising; under a distinct frontal plate, first joint elongate 

 conical pilose, second short glabrous at base, 3 — U equal and, with the apex of 

 the second, pubescent. Clypeus prolonged at middle. Head depressed, quadrate, 

 two approximated supra-orbital setse. Eyes small oval, truncate posteriorly, very 

 distant beneath from the buccal fissure. Labruni sinuate or denticulate. Mandi- 

 bles strongly arcuate, either dentate or simple within, scarcely concave externally 

 without setigerous puncture. Maxillae ciliate within, the outer lobe with terminal 

 joint longer, palpi stout, the joints with short hairs, the terminal shorter than the 

 preceding, oval, truncate at ti[). Mentum large almost entirely concealing the 

 maxillfe, the suture at base indistinct, deeply emarginate and with a large bifid 

 tooth, ligula large prominent, slightly emarginate in front and plurisetose, the 

 paraglossse corneous and closely united with it, palpi moderate, last joint securi- 

 form. Thorax narrowed at base, grooved above and with a setigerous puncture 

 on the hind angle and others along the side margin. Body pedunculate. Elytra 

 elongate-oval, depressed, sides narrowly inflexed, margin entire, base not margined. 

 Prosternum not prolonged. Mesosternum rather widely separating the coxsp, 

 horizontal, the epimera narrow and not attaining the coxal cavity. Metasternal 

 epimera small but distinct. Posterior coxae slightly separated, the first ventral 

 segment distinct between them. Anterior tibiae emarginate within and deejily 

 obliquely grooved, the inner spur superior. Tarsi simple in the two sexes. 



This group contains but one genus Slngona (possibly also Luperca = 

 Holosceh's), not represented in our fauna. It has been made by most 

 authors the type of a tribe and placed in the Carabinfe. The Siagonides 

 of European authors contains two very dissimilar elements. Enre/adns 

 and Lnperca (?) having the middle coxfe partially closed extei'nally by the 

 mesosternal epimera form in the present essay the tribe Enceladini of 

 the sub-family Carabinje. Siogonn on the other hand has the meso- 

 sternal structure of the present sub-family and Schioedte, Schaum and 

 Chaudoir have been deceived by a mere plication in the mesosternal side 

 pieces and have been lead to believe that the mesosternal epimera reach 

 the coxae. By macerating a specimen of Stngnna for a sufficient time 

 in a solution of caustic potassa the sutures become apparent and will be 

 found as stated above. 



The latest review of the Siagonini is that published by Baron Chaudoir 

 (Bull. Mosc. 1876), in which Evrefadus still retains its place in the 

 tribe. In recognizing the great value of the discovery (which we owe 

 to Dr. LeConte), of the diiference in form of the mesosternal epimera in 

 the sub-families of Carabidae, Chaudoir states that in associating Slngona 

 with Encehidiii^ one reasons rather by arialogy as the suture which sepa- 



