20 Mr. G. R. Waterhouse on Coleopterous Insects 



which cannot be located in any known genus, but which apper- 

 tain to families having representatives in most parts of the world, 

 such as the Pedinidce, Tentyriidce, Anthribidce and Haliicidce. 



But four species amongst the Galapagos Coleoptera occur, so 

 far as I have been able to ascertain, in any other quarter, and of 

 these, two {Dermestes vulpinus and Corynetes rufipes) are insects 

 which, feeding upon dried meat and such substances, have been 

 carried 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 insect 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 1 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 he four great 

 families of Rodents. In the order Fac/ii/dermata, the various species appear 

 all to approach more or less to four principal forms, typified by the genera 

 Equus, I'dpir, 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, Cicindelidce, 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 — i\\e Psittacidce 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. 



