156 GEO. II. HORN, M. D. 



cond joints small, terminal equal to the two preceding. In the accom- 

 panying cut the palpi are pushed farther back than in nature, in order 

 that the individual parts might be better represented. 



Mentum (jj') large, connate with the gula without trace of suture, 

 f)- entirely concealing the parts of the mouth abo^^e. deeply emar- 

 ginate, with a broad tooth at the bottom of the emargination, 

 lobes obtusely rounded. Lateral sutures of gula distinct. 

 In his work on the genera of Coleoptera, Lacordaire commits 

 the curious mistake of ascribing a totally different form to the ligula 

 I'rom that indicated by the above description ; he says, " languette en 

 forme de T." This mistake originated from a misinterpretation of the 

 meaning of Dr. Leconte, (^Froc. Ac. 1. c.) in the lirst description of 

 the insect, as follows: — "The ligula is large, filling the emargination 

 of the chin, truncate at tip and prominent along the middle and apex, 

 so as to present a form like the letter T." The inner lobes of the 

 maxillae are ciliate internally, and not as Lacordaire says, "lobe interne 

 des machoires non cilie." The above-named author had, however, no 

 opportunity of examining the insect, as no specimens had been sent 

 abroad at the time the above extracts were written. 



In the above descriptions of the head and parts of the mouth, hard- 

 ly anything can be found in which this insect differs from the Carabi- 

 dae. The large size of the mentum is remarkable, also the absence of 

 the gular suture, a character found only in a few Pseudomorphides and 

 Siagouides,* the former being, however, insects of a very anomalous 

 form, and whose claim to rank as members of the ftimily Carabidae has 

 been doubted by various entomologists. In Metrms more particularly, 

 and in other Carabidae, the mentum is large, broad, and deeply emar- 

 ginate, though never so entirely biding all the parts above it, as in 

 Amphizofi. The antennai are also anomalous in being entirely glab- 

 rous, without pubescence, and only a few punctures on their upper 

 surface. 



Prothorax narrower than the elytra and in close contact witli them, 

 nearly twice as broad as long, narrower before than behind, sides ob- 



*The form of mentum among these insects is very similar to that seen in 

 j4/n.jo/ii2oa, particularly i\\a,i oi Enceladus, where the suture is entirely obliterated. 

 In fact, its mentum might well represent an enlarged view of that of ^nyj/u'zoa, 

 excepting in the form of the tooth at tlie bottom of the excavation. Notwith- 

 standing its large size in the Siagouides and Ditomides, the mentum never 

 hides so completely the other' parts of the mbuth, as in Amphizoa. The man- 

 dibles are very prominent in the two tribes mentioned above, and in Enccladas 

 recalling the form met with among the Scaritides, i)articularly Pasiinachas. 



