Sound-pTodudion in the Lamellicom Beetles. 745 



intermedio armatis ; appendiculis dorsalibus stridulatoriis fusi- 

 formibus. 



Long. 6-7" 5 mm. 



Hal). Argentina, Chaco, and Rio las Garzas. 



There are six specimens which appear to be all females. 

 They may perhaps be most conveniently compared with 

 the European 0. chnjsomelinus, F., the general form and 

 size being similar. This species is much less finely and 

 closely rugose than that, the elytra are more^ deeply 

 striated, the clypeus is very small and not distinctly 

 marked off from" the rest of the head, and the jaws are 

 considerably longer, their tips unequal and rather blunt 

 and their outer margins irregular. 



Hitherto only a single species of Ocliodwus (0. rugatus, 

 Westwood) has been known from South America. In the 

 British Museum collection, in addition to that insect and 

 0. campsognathus, there is a specimen of yet a third 

 which it will be well also to characterize. 



0. tridentatus, sp. n. 



Ovatus, pallide testaceus, sat nitidus, vertice, protliorace, sutura, 

 corporeqne subtus obscurioribus, clypeo modice producto, grosse 

 rngoso, longe setoso, fronte grosse, baud crebre, punctato, oculis 

 magnis; prothorace grosse et regulariter punctato, antice paulo 

 angustato ; scutello sat angusto, acuminate ; elytris fortiter punctato- 

 striatis, interstitiis impunctatis, parce granulatis, cum prothorace 

 subtiliter flavo-setosis ; elytrorum apicibus sinuatis, angulis fere 

 spiniformibus ; propygidii margine posteriore medio retuso, bidentato ; 

 pedibus flavis, tibiis anticis tarsisque obscurioribus, illis tridentatis, 

 dentibus tequidistantibus ; tarsis anticis gracilibus, reliquis sat 

 robustis. 



Long. 8-5 mm. 



Hah. Colombia. 



The type was derived from the Reiche collection, where 

 it bore the unpublished name '' xquinoctialis, Dupont." 

 The species is rather less short and globose than usual. 

 The head is not very transverse, the eyes are large and 

 the prothorax is narrowed anteriorly and widens to beyond 

 the middle. The sculpture is everywhere coarse and the 

 setose clothing is inconspicuous both above and beneath. 



Ochod/eus was associated by Erichson with Orphmis, 

 Hijhalus and ^gidmm in a family (Orphnidse) which he 



