Mr. G. R. Waterhouse on some Coleopterous Insects. 19 
between leaves and petals in the situation of the colours; and 
the location of the colours of the petals in‘the rete, a fact hitherto 
unnoticed, and one which may hereafter throw light on some 
interesting points of vegetable physiology. 
Reference was made to another kind of colours, also found in 
the leaves and petals. These, with their peculiarities, which may 
prove not devoid of practical imterest, together with some other 
matters connected with the subject or suggested by it, remain to 
be brought forward at some future time. 
London, June 9, 1845. 
V.—Descriptions of Coleopterous Insects collected by Charles 
Darwm, Esq., in the Galapagos Islands. By Groren R. 
Warternovse, Esq. 
Tue insects here described are nearly all of small size, and none 
of them display any brilliant colourmg. Some of the species are 
referable to a little group found m Chile and Peru,—the genus 
Ammophorus, a genus hitherto only found in those parts ; others 
appertain to a genus (Anchonus) which is almost confined to the 
West Indian islands and the northern parts of South America. 
Again, in the collection under consideration are species of ge- 
nera which are found all over the world or nearly so, such as 
Feronia, Notaphus and Oryctes* ; and, lastly, there are species 
* It is from genera like these, which have a very wide geographical range, 
that the minor, local groups appear as it were to radiate. ‘hose genera 
which are confined to comparatively limited districts, often containing but 
few species, and also often presenting very remarkable abnormal medifica- 
tions of structure, are in most cases referable to some family which has re- 
presentatives in most parts of the world. Groups of high value, such as 
classes, are never confined to any particular quarter of the globe; and 
even when we descend to families, restricted as they now are by natu- 
ralists; it is comparatively rare to find them so defined as not to embrace 
species from widely separated localities. Genera may be arranged under 
three principal categories as regards their geographical distribution. First 
may be noticed those of universal range, such as Cicindela; secondly, those 
which occur in both hemispheres but affect particular zones, such as Mega- 
cephala, which is confined to the tropical zone; and thirdly, those which are 
restricted to.a comparatively small district, such as Manticora, which is con- 
fined to South Africa, ‘hese genera all belong to the same family of beetles, 
and of this family Manéicora presents certainly one of the most aberrant 
forms. The genus Cicindela would by most entomologists be regarded as 
the typical genus of the family Cicindclid@, and here we find, as in many 
other cases, the presumed typical genus has a universal range; it may be 
inquired, therefore, whether such is not generally the case. 
I must here observe that Mr. Swainson has expressed the opinion that 
typical genera have a great geographical range; I was not aware, however, 
of this fact until after the idea had been suggesied to me by a tabular ar- 
rangement which I had formed of the Mammalian order Rodentia, in which 
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