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rower in front than behind ; the lateral margins form an even curve ; 
the anterior part is emarginated, the emarginated portion being in 
the form of a segment of a circle, and a little less than a semicircle : 
the anterior angles acute, and the posterior angles form very nearly 
right angles: the hinder margin of the thorax is nearly straight, but 
the line descends slightly towards the angles. The surface of the 
thorax is very little convex, and almost impunctate, there being but 
a few scattered very minute punctures ; on the sides, running inwards 
and upwards, are a series of minute grooves, like scratches, and on 
the hinder margin a faint trace of very short longitudinal grooves 
is visible. The elytra are ovate, convex, smooth, and glossy; the 
region of the suture is broadly and rather deeply depressed; the 
lateral keel is prominent and distinctly crenulated, and joining this 
keel are a series of shortish transverse furrows. ‘The under sur- 
face of the body and thoracic segments is remarkable for the almost 
total want of sculpturing, if we except some longitudinal furrows 
on the under side of the prothorax at the sides. 
The exact habitat of the specimen from which the above descrip- 
tion is taken is not known, but in Mr. Darwin’s collection is a spe- 
cimen which I am inclined to regard as specifically identical, and 
which is from St. Julian. It has the elytra proportionately rather 
broader and the thorax narrower, and the short longitudinal furrows 
on the hinder margin of the thorax are distinct ; the sutural portion 
of the elytra is less depressed. 
Nycretia Guerinu. Nyct. atra, nitida, ovata ; capite transversim 
impresso ; thorace subquadrato in medio pauld dilatato, antice 
emarginato, postice fere recto ; ad marginem lateralem sulcis mi- 
nutis valde obliquis insculpto ; elytris ovatis, convexis, ad apicem 
pauld productis, ad latera rugis transversis in seriebus tribus 
dispositis. 
Long. corp. 95 lin.; lat. 53 lin. 
Hab. St. Cruz. 
Rather smaller than N. levis. Head with small punctures very 
thinly scattered over the upper surface, and with a transverse im- 
pression rather in front of the line of the eyes. Thorax subqua- 
drate, the breadth not quite equal to twice the length; the emar- 
ginated portion in front in the form of a segment of a circle; the 
hinder margin nearly straight; the posterior angles scarcely pro- 
duced, and forming nearly right angles; the anterior angles acute. 
‘The thorax is contracted in front, broadest in the middle, and the 
lateral margin from the middle to the posterior angles forms nearly 
a Straight line: on the hinder part of the upper surface are some 
extremely minute punctures, and at the sides are some small ob- 
lique grooves. ‘The elytra are ovate and moderately convex, and 
the apical portion is but little produced; the region of the suture 
is very slightly indented: the sides of the elytra are covered with 
transverse grooves having narrow convex interspaces ; these grooves 
extend inwards to about the middle of each elytron, and are arranged 
in three series, being divided by two longitudinal lines ; the innermost 
