2 
PREFACE. 
lamented friend Latreille as a model, Nature has been my 
Guide ; for with the exception of some of the caterpillars, 
living examples of which it was impossible to obtain, and a 
very few of the dissections, every figure has been drawn from 
the life or from preserved specimens, and the descriptions 
have been taken from actual investigations of the various 
parts of the animals. 
Desirable as it seemed to be that a work on Genera should 
be offered to the public, it appears rather strange that one 
should not have been earlier attempted, especially as the cele- 
brated author of the “ Natural History of Selborne” observed 
fifty years since, that “ nothing would recommend Entomo- 
logy more, than some neat plates, that should well express 
the generic distinctions of insects according to Linnaeus.” 
In following up this object I have not confined myself to 
a close investigation of one set of characters, being convinced 
that a truly philosophic System must be based on all that are 
available, and which consequently must be derived from va- 
rious sources : in this conclusion I am borne out by consider- 
ing the result of the opposite plan pursued by the most 
learned men who have written upon the subject ; for instance, 
Linnaeus depended upon the antennae; Fabricius upon the 
organs of manducation ; Geoffrey upon the tarsi and antennae ; 
Jurine upon the wings ; each adopting circumscribed and ar- 
tificial instead of general features for his basis, without suffi- 
ciently regarding the value of others as secondary charac- 
ters*: but surely it is a fallacy to suppose that one set of 
characters is to be employed almost to the exclusion of all 
others, although it is not to be denied that in different Orders 
their value varies essentially. To illustrate this position the 
Order Coleoptera may be taken ; the leading groups I consi- 
der, such as Latreille’s five principal Sections, may be cha- 
racterized, with modifications, by the structure of the tarsi ; 
the families of the same author are best identified by the 
trophi; the antennae will distinguish genera , such as my 
views are of them; texture and sculpture ought to be the 
leading features of species ; and colour seems to be the eva- 
* It is true that Fabricius and Jurine have noticed other characters, but 
it must be inferred from their laconic and superficial descriptions, that lit- 
tle importance was attached to them. 
