38 
Mr. H. W. Bates on 
According to Lacordaire^ the Longicorns are divisible 
into three tribes ; the Lepturidesj formerly considered by 
most authors as a fourth tribe^ being sunk to the rank of 
a subordinate group under the Cerambycides. Having 
traced the successive modifications of the forms allied to 
LepturideSy in the order given by Lacordaire, I have 
recognized the justice of this arrangement, and the error 
of the opinion expressed in the introduction to the 
Lamiides of the Amazons, on the same subject. The 
Prionides are distinguished from the two other tribes by 
the pronotum being distinct from the flanks of the pro- 
thorax, and by the anterior coxse lying in transversely- 
elongated sockets. In common with the Cerambycides ^ 
they differ from the Lamiides, by the palpi never termi- 
nating in points, and the anterior tibiae being simple 
instead of grooved on their inner sides. 
The number of Prionides obtained by me from the 
Amazons is only twenty- six ; a small proportion of the 
whole number found in Tropical America, namely 166. 
A great many, however, described from other quarters, 
will probably be found to be varieties or opposite sexes 
of other species ; in confirmation of which opinion I may 
point to the seven false species of one genus only, Pyrodes, 
which I have reduced to synonyms in the following 
descriptions. But the equatorial plains seem to be less 
rich in the group than the borders of the tropics, or the 
mountainous regions. The species are mostly nocturnal 
in their habits, and of great rarity. When found 
in situ, it is generally on the trunks, or under the 
bark, of the largest forest trees. They fly abroad at 
night, and are sometimes overtaken by a sudden storm, 
and cast into lakes or rivers, whence the swell carries 
them to the sandy beaches ; several of the species here 
recorded have been found under these circumstances. 
I have not thought it necessary to insert in the Prionides 
the sections and tribus of Lacordaire; the genera 
follow in the order of his classification. 
I. Prionides abereantes. 
Genus Parandra. 
Latr. Hist. Hat. des Crust, et Ins. xi. p. 252. 
1. Parandra gracillima, n. sp. 
P. elongata, angustata, mandibula dentibus molaribus 
basalibus contiguis, apice tridentatis, orbitu oculorum 
