20 Mr. G. R. Waterhouse on Coleopterous Insects 
which cannot be located in any known genus, but which apper- 
tain to families havmg representatives in most parts of the world, 
such as the Pedinide, Tentyriide, Anthribide and Halticide. 
But four species amongst the Galapagos Coleoptera occur, so 
far as I have been able to ascertain, in any other quarter, and of 
Y 
these, two (Dermestes vulpinus and Corynetes rufipes) are insects 
which, feeding upon dried meat and such substances, have been 
earried to all parts frequented by ships; the third is a wood- 
feeding insect (genus Apate), and might be transported for a con- 
siderable distance by floating timber ; and the fourth is a water- 
beetle which appears to me to be clearly identical with the Hy- 
drophilus lateralis (genus Tropisternus of Solier), an inseet found 
in the United States, Mexico, and some of the West Indian 
islands. I should observe, moreover, there is in the collection a 
second, minute, species of Hydrophilus closely resembling the 
Philhydrus affinis of our English collections, but which is rather 
smaller, less distinctly punctured, and of a darker hue. I have 
in my collection a species from North America from which the 
Galapagos Philhydrus differs only in being of a darker colour ; 
perhaps this little Hydrophilus should therefore be incorporated 
amongst the species which are not peculiar to the Galapagos 
Islands. Some of the insects of the collection have labels at- 
tached, from which may be ascertained the particular island of the 
Galapagos group from which they were procured, and where this 
was the case I have not found any species which is common to 
two or more of the islands. 
both the classification of the minor divisions and their geographical distribu~ 
tion were displayed at the same time. After working out the affinities of the 
groups of the Carnivorous quadrupeds, the idea again occurred to me; five 
out of the six great divisions | had formed from the consideration of characters 
furnished by the skull and dentition combined, had a typical form of very 
great geographic range. In the order Rodentia I had made three great di- 
visions, and had pointed out the distinguishing characters of a fourth, though 
I hesitated to raise that fourth to the rank of the other three. Were the 
geographical range to be taken into consideration, there would be four great 
families of Rodents. In the order Yachydermata, the various species appear 
all to approach more or less to four principal forms, typified by the genera 
Equus, Tapir, Sus and Mastodon, and these genera, or very nearly related 
genera, are found either living or in a fossil state in all the principal quarters 
of the globe, Australia excepted, where only the last has been found. What 
is characteristic of part of a small group might also be characteristic of part 
of a larger group. I have noticed that in a certain family, Cicindelide, one 
genus is confined to a tropical zone; so might we find in an order of ani- 
mals, a family which is confined to the tropical zone—the Psittacide among 
Birds is nearly a tropical family ; and in the class Mammalia we have an in- 
stance (certainly a rare one) of an order (the Quadrumana) which is almost 
confined to the tropical zone. The sections of water insects have generally 
a wider range than most others, and the above generalizations, as regards 
the distribution of groups, will not apply to parasitic insects. 
