92 Mr. Malcolm Burr’s Preliminary Revision of the 
character, that I prefer to employ it to define this family ; 
it does not seem likely that the shape of this segment has 
any direct influence upon the insects’ life or habits; it is 
probably a relic of some ancient specialisation, and there- 
fore unlikely to be so subject to fluctuation as an organ in 
activity, the lateral stink-glands for instance, which vary 
with the age of the individual. It is also by the rudi- 
mentary remains of once active organs that we may best 
hope to trace the natural affinities of the different species, 
which is the ultimate aim of all classifications. 
Dr. Verhoeff’s work is very valuable, and it is a pity 
that he marred it by such faults as the incorrect use of 
the name Sphingolabis, and the separation of Cosnviella based 
on the absence of wings, a character upon which Ortho- 
pterists and Dermapterists are agreed it is useless to found 
even a species. 
The synoptical tables for the determination of species 
must not be regarded with too critical an eye; they are 
offered with no attempts at dogmatism, but only as help- 
notes for entomologists who wish to determine earwigs. 
It will be observed that several new characters are 
used. Greater stress than previously is here laid upon 
the form and relative sizes of the first four or five segments 
of the antennz, and also on the form of the pronotum 
and legs. Verhoeff used the carina of the elytra in a 
few instances; in certain genera the slight fold, which 
roughly divides the elytra into a large dorsal and a small 
and narrow costal or lateral portion, is emphasised and 
strengthened into a sharp ridge or keel, which in some 
cases extends the whole length of the elytron, and in 
others dies out half-way down. More attention is also 
paid to the shape of the abdomen. 
The chief point which leads me to hope that this 
attempt at a new classification will be found to approach 
more nearly to the true natural arrangement is the fact 
that the groups are now divided more or less according to 
their geographical distribution. Formerly, Opisthocosmia 
was regarded as a characteristically Asiatic genus, until 0 
americana and O. amazonensis were described from South 
America; conversely, the discovery of Ancistrogaster yavana 
robbed that genus, in its old sense, of its peculiarity to 
America. But a glance at the tables proposed in the 
following pages will show that true Opisthocosmia, as now 
defined, is confined to the tropical regions of the Old World, 
