1918.1 153 



intermediate coxae, together with the large mentum filling the gular 

 cavity, place it among the early groups of this family far removed from 

 the Rht/sopaussinae. The anterior coxal cavities are placed. very far 

 back and are almost contiguous, being separated by a very narrow 

 partition, which is sunk between the coxae and scarcely visible without 

 dissection ; and the antennae are apparently 10- jointed, the 11th joint 

 being sunk within the 10th. In these features, as Avell as in the deeply- 

 excavated thorax, Tretothorax agrees very closely with the American 

 genus DacoderuB Lee. In the latter the anterior coxal cavities are 

 described as contiguous, but having no specimen to spare for dissection 

 I am unable to satisfy myself whether this is really so, or whether there 

 is not a narrow sunken division between them. In either case Treto- 

 tliorax undoubtedly finds its nearest described ally in Dacoderus, and 

 may well be included with it in the subfamily Dacoderinae. An affinity 

 between two such specialized genera, each so isolated in its peculiar 

 fauna, is somewhat surprising, but the resemblance between them, 

 extending even to such superficial details as the character of the elytral 

 sculpture, is really remarkable. 



Dctcoderus striaticeps is described as living under bark, nothing 

 being said of its having any association with ants or termites, though 

 it is not improbable that such may exist. 



There are three described species of Dctcoderus — one from Cali- 

 fornia and N. Mexico, one from Texas, and one from San Domingo. 

 The British Museum possesses a fourth and very distinct species from 

 Colombia, viz. : — 



Dacoderus acaiithomma, sp. n. 



Elongate, reddish castaneous, iiitid ; genne not produced behind the eyes, 

 but enclosing' them beneath, and visible Ironi above as a narrow external 

 border, which is produced opposite the posterior part of the eye into a tooth 

 directed a little forwards. Front of head deeply excavate between the 

 antennary bosses, the vertex strongly, longitudinally sulcata. Thorax strongly 

 sulcate before the transverse excavation, the median furrow in this area not 

 strongly pronounced. Elytra elongate ovate, flat on the disc, the sides perpen- 

 dicular, separated from the disc by a carina, which is strongly pronounced on 

 the shoulders, but obsolete towards the apex; suture raised; the first stria 

 distinct, its interval uniseriately punctate, the rest of the elytral surface with 

 in'egularly disposed elongate punctures. 



Length 4 mm. 



Hah. Colombia {ex coll. Fry), 



One example. Closely allied to D. striaticeps Lee, next to which 

 it comes in Horn's synopsis of the genus (Trans. Amer. Ent, Soc. xx, 



