110 
with and near the lateral margin; the narrow ridge between the 
two grooves, as well as the marginal ridge, is crenulated. 
Nycretia PuncTicoLuis. Nyct. ovata, atra, nitida ; thorace di- 
stincté et crebré punctato ; elytris tuberculis minutis, et ad latera 
rugis transversis irregularitér impressis, his non forte distinetis. 
Long. corp. 93 lin. ; lat. 6 lin. 
Hab. Bahia Blanca. 
This species is rather smaller than the N. Zevis, and has the tho- 
rax and elytra less convex. The head is rather thickly and coarsely 
punctured, excepting on the vertex. The thorax is thickly and 
coarsely punctured, and the punctures are for the most part con- 
fluent ; a distinctly impressed line runs parallel with and close to the 
margins; the lateral margins are obscurely crenulated. ‘The elytra 
are of a broad ovate form, and the apical produced portion is convex 
and rounded at the apex. ‘The lateral keel of the elytra is distinctly 
crenulated, and transverse shallow furrows run inwards from this 
margin, leaving interspaces rather broader than the furrows, which, 
for the most part, are about a line, or rather less, in length. On 
the interspaces between the furrows, and the whole upper surface 
of the elytra, are very minute scattered tubercles; these are very 
indistinct towards the suture, near which are one or two very faint 
strie. The labrum is coarsely punctured, and the underside of the 
head is also punctured. ‘The under surface of the prothorax is 
covered with small tubercles, from each of which springs a hair; 
between the legs, the under side of the prothorax and mesothorax 
is coarsely punctured. The first, second and third of the abdominal 
segments are covered with distinct longitudinal rug, and the apical 
segments are punctured beneath. 
Several specimens of this species were collected at Bahia Blanca 
by Mr. Darwin, who says they are ‘tolerably abundant on sand- 
hillocks.’. A Nyctelia in Mr. Darwin’s collection, from Rio Negro, 
resembles the present species, excepting that it has pitchy red legs 
and antenne. 
Nycrenia sussutcatTa. Nyct. ovata, atra; thorace transverso 
distincté punctato ; elytris rugis tuberculisque minutissimis ; sulcis 
transversis aliquanto irregularibus ad latera insculptis. 
Long. thoracis elytrorumque, 94 lin. ; lat. 52 lin. 
Hab. Mendoza. 
This species is very closely allied to the N. puncticollis, and it is 
with considerable hesitation that I venture to describe it as distinct, 
more especially as Mr. Darwin’s collection contains but one speci- 
men, and that has lost its head and legs; this specimen, however, 
differs considerably in form from any of the numerous examples of 
N. puncticollis which I have before me. The thorax is narrower 
and less thickly punctured; the elytra are more elongated, and the 
lateral transverse grooves are more distinct and regular. 
The thorax is transverse, and the length is equal to rather more 
than half the width; the middle and hinder parts are very nearly 
equal in width, and the anterior portion is contracted ; the surface is 
