North-western Argentine and Bolivia. 461 



(in spirit), becoming light greyisli brown towards the poste- 

 rior half of tlie body ; tail paler, being in the older specimea 

 light brownish grey, in the younger more reddish, almost 

 dull brick-red. The younger specimen is also more brownish 

 or olive on top of the head and neck, so that the bluish-green 

 colour is most prominent on tlie sides of the neck and body, 

 where the scales have that colour, but are edged with light 

 brownish. A blackish stripe extends from the nostril, through 

 the lower part of the eye along the upper margin of the upper 

 labials, which otherwise are whitish. This dark stripe dis- 

 appears on the neck. Below greenish blue anteriorly, be- 

 comingraore greyish (orreddish in the youngerone) posteriorly; 

 a whitish band occupies the lateral ends of the ventrals and the 

 lower half of the outer row of scales. This band is con- 

 spicuous to the anus, where it disappears. The tail has about 

 the same coloration below as above, only lighter below. 



The larger specimen from Crevaux, Bolivian Chaco, 

 measures li\ centim. in total length, the tail is 23^ centim. 

 The smaller specimen is from Tatarenda *. 



Ela-ps frontalis^ Dura. & Bibr. 



I refer to this species a rather large specimen from Tata- 

 renda measuring about 124 centim. It has eight sets of 

 black annuli ; upper head-shields black, edged with yellow ; 

 only three lower labials in contact with the anterior chin- 

 shields ; tail ending very obtusely. With these characteristic 

 features it combines, however, a rather large numberof shields, 

 namely, ventrals 246 and subcaudals 28. I think, however, 

 that this does not prevent the identification from being correct, 

 because the variability of the species seems to be rather large 

 with regard to the number of shields. 



Leptognathus Mikani (Schleg.), 

 One specimen from the Bolivian Chaco. 



Leptognathus turgida, Cope. 

 Three specimens from Tatarenda, Bolivian Chaco. 

 Lachesis Neuwiedi, Wagler. 



Three specimens from Quinta, Province de Jujuy, Ari-en- 

 tine, and six from Tatarenda, Bolivian Chaco. 

 It is known under the name of " Vibora." 



* I have had the pleasure of consulting Mr. G. A. Bouleno-er con- 

 cerning this new species, and beg therefore to offer him my thanks for 

 his kindness. 



