are generally recognized; the
difficulty that confronts the zoologists is the arrangement of these
families in "superfamilies" or "sub-orders." Such obvious features as
the number of segments in the foot and the shape of the feeler were
used by the early entomologists for distinguishing the great groups of
beetles. The arrangement dependent on the number of tarsal segments--the
order being divided into tribes _Pentamera_, _Tetramera_, _Heteromera_
and _Trimera_--was suggested by E. L. Geoffroy in 1762, adopted by P. A.
Latreille, and used largely through the 19th century. W. S. Macleay's
classification (1825), which rested principally on the characters of the
larvae, is almost forgotten nowadays, but it is certain that in any
systematic arrangement which claims to be natural the early stages in
the life-history must receive due attention. In recent years
classifications in part agreeing with the older schemes but largely
original, in accord with researches on the comparative anatomy of the
insects, have been put forward. Among the more conservative of these may
be mentioned that of D. Sharp (1899), who divides the order into six
great series of families: _Lamellicornia_ (including the chafers and
stag-beetles and their allies with five-segmented feet and plate-like
terminal segments to the feelers); _Adephaga_ (carnivorous, terrestrial
and aquatic beetles, all with five foot-segments); _Polymorpha_
(including a heterogeneous assembly of families that cannot be fitted
into any of the other groups); _Heteromera_ (beetles with the fore and
intermediate feet five-segmented, and the hind-feet four-segmented);
_Phytophaga_ (including the leaf-beetles, and longhorns, distinguished
by the apparently four-segmented feet), and _Rhynchophora_ (the weevils
and their allies, with head prolonged into a snout, and feet with four
segments). L. Ganglbauer (1892) divides the whole order into two
sub-orders only, the _Caraboidea_ (the _Adephaga_ of Sharp and the older
writers) and the _Cantharidoidea_ (including all other beetles), since
the larvae of _Caraboidea_ have five-segmented, two-clawed legs, while
those of all other beetles have legs with four segments and a single
claw. A. Lameere (1900) has suggested three sub-orders, the
_Cantharidiformia_ (including the _Phytophaga_, the _Heteromera_, the
_Rhynchophora_ and most of the _Polymorpha_ of Sharp's classification),
the _Staphyliniformia_ (including the rove-beetles, carrion-beetles