On a remarkable Mountain Viscacha. 439 



finely punctured, and the pjgidium and underside are strongly 

 punctured. 



Tlie female is more finely punctured and almost devoid of 

 setie, witii the head simple and slightly pointed in front. 

 The prothorax is minutely and not closely punctured, without 

 a median carina, and is rather more sharjjly anguhxted at 

 the middle of the base. The elytia and underside are also 

 more finely punctured than in the male. 



The species is remarkable for the extraordinary structure 

 of the antennse characteristic of the male, which is quite 

 unlike anything hitherto known. The last three joints of 

 the footstalk are broad and close-fitting, and the seventh joint 

 forms a hollow half-hemisphere, covering the two remaining 

 joints as seen from beneath. The eighth joint sends off a 

 slender branch on each side, and each branch is toothed 

 underneath ; and the last joint has a slender footstalk, which 

 gives off two similar toothed branches on each side, dimin- 

 ishing in length, and is broad at the end, partly shuttin<;- 

 in at the extremity of the antenna the whole complicated 

 apparatus. 



The antennae of the female are quite normal. 



A series of specimens, chiefly males, have been obtained 

 by M. Rene Oberthiir's collectors. 



LI. — On a remarkable Mountain Viscacha from Southern 

 Patarjonia, with Diagnoses vf other Members of the Group. 

 By Oldfield Thomas. 



The Briti.sh Mu.-eum owes to its gen-^rous and indefatigable 

 contributor, Mr. J. A. WcdfTsohii, C.M.Z.S., three examples of 

 a fine Viscaccia^ from a locality far south of any place where 

 members of this group have been previously recorded. 'J'he 

 animal is quite distinct from any hitherto known, and I 



* In his paper on the nomenclature of this group, Dr. F. Lahille 

 (An. Soc. Cient. Ar^rent. Ixii. p. 39, ](X)6) sionis to Lave come to quite 

 correct conclusions, including the allocation of Viscarcia to the Mountain 

 Viscachas, formerly known as Layulium. Hut with the fate that hns 

 as yet always befallen writers on this most difficult and complicated 

 subject, he lias made a mistake in crediting the name Viscncciaio .Molina, 

 for although the latter did say in IblO that the animal ought to have a 

 special generic name, he did not give it one, only using Viscaccia in such 

 a way that it cannot be distin^Miished from the vernacular tt-rm. 

 However, fortunattly, Oki-n in ISlti used the term Viscaccia in a techni- 

 cally valid manner, with " Lepus chilensi* '' as its type, choosable as 

 such whether by elimination or by the first-species rule. 



