PLATE XXIII.
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(ORDER—COLEOPTBRA. SE C T I O N—L O N G I O O H N E S . FAMILY—TnicTENOioMiDiE. WESTW.)
THE first notice of tlie type of this very anomalous groux) of insects appeared in a note appended to
a paper of mine in the 18th number of the "Zoological Journal," (published in 1830,) in which I
regarded it as a connecting link between the Prionidoe and Lucanidie, agreeing with the former in its
general appearance, short trigonate advanced mandibles and moderately long antennae, whilst in the
internally produced structure of the three terminal joints of the antennEe it agrees with Lucanus ;
observing, moreover, that the joints of the tarsi are cylindric (as in the latter), but the insect is
heteromerous !
Shortly afterwards a figure of the type Trictenotoma Childi-enii was published from a drawing of
mine in the plates to Griffith's edition of the "Animal Kingdom," and M. Guerin Ménéville also gave
a figure of it in his " Magasin de Zoologie," pl. 35, with a notice by M. Dupont in which the position
of the genus was considered to be " en tête des Longicornes, famiUe ou, par tovis ses rapports il entre
tout naturellement."
During the period which has since elapsed no further attempt has been made to investigate the
affinities of the genus by an examination of its strnctm'al characters. Having, however, recently
received a specimen of T. Childi'enii from Assam bji" the kindness of Major Jenkins, and two other
new and very distinct species ha\dng also been recently received in this country, I have submitted the
whole to a careful investigation, the result of which is before the student in the accompanying plate.
From the considerations derived from the structure not only of the mouth organs but also the
position of the wing veins and numerical ai'rangement of the abdominal segments, I have no longer
any hesitation in referring the insect to the section Longicornes, notwithstanding the internally
produced terminal joints of the antennaî (which is too tri-sdal a character to be considered of high
importance in limiting the groups), the heteromerous tarsi, and the structure of the organs of generation.
Moreover, its nearest aiBnities appear to be the Prionidoe, especially in the porrected head and
mandibles, moderately short antennoe, sHghtly emai-ginate eyes, and wing veins. Pi>om these, however,
it differs in several respects, so that I have considered it more natural to regard it as the type of a
distinct family, which may be thus characterised.
TRICTENOTOMIDiB. WESTW.
Head horizontal ; eyes transverse, slightly emarginate behind the base of the antenuie ; labrum short,
transverse ; mandibles porrected, nearly alike in both sexes. Maxillae with the inner lobe scarcely
produced, outer lobe long, narrow, and hah-y ; mentum broad, with the sides elevated ; labium short,
bipartite ; antennai moderately long ; those of the males rather more elongated ; three terminal joints
internally serrated. Pronotum with the hind margin lobed in the middle ; wings folded at about threefourths
of their length from the base ; abdomen Avith seven dorsal and five ventral segments ; the
terminal dorsal segment in the male notched ; the terminal ventral segment in the same sex more deeply
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