Of the Cerambycidæ there are 233 genera, exceeding by one-half, the number in any other region; and 225 of these are peculiar. Only 2 are common to the Neotropical and Nearctic regions exclusively, and 3 to the Neotropical and Australian. The most extensive genera are the elegant _Ibidion_ (80 sp.); the richly-coloured _Chrysoprasis_ (47 sp.); the prettily-marked _Trachyderes_ (53 sp.); with _Odontocera_ (25 sp.); _Criodon_ (22 sp.); and a host of others of less extent, but often of surpassing interest and beauty. The noteworthy genera of wide range are, _Oeme_ and _Cyrtomerus_, which have each a species in West Africa, and _Hammatocerus_, which has one in Australia. The Lamiidæ have 219 genera, and this is the only tropical region in which they do not exceed the Cerambycidæ. This number is almost exactly the same as that of the Oriental genera, but here there are more peculiar groups, 203 against 160 in the other region. The most extensive genera are _Hemilophus_ (80 sp.), _Colobothea_ (70 sp.), _Acanthoderes_ (56 sp.), _Oncoderes_ (48 sp.), _Lepturgus_ (40 sp.), _Hypsioma_ (32 sp.), and _Tæniotes_ (20 sp.). _Macropus longimanus_, commonly called the harlequin beetle, is one of the largest and most singularly-marked insects in the whole family. _Leptostylus_ has a single species in New Zealand; _Acanthoderes_ has one species in Europe, W. Africa, and Australia, respectively; _Spalacopsis_ has a species in W. Africa; _Pachypeza_ is common to S. America and the Philippines; _Mesosa_ is Oriental and Palæarctic, but has one species on the Amazon; _Apomecyna_ ranges through the tropics of the Eastern Hemisphere, but has two species in S. America; _Acanthocinus_ has one species in Tasmania, and the rest in South America, North America, and Europe; _Phæa_ is wholly Neotropical, except two species in the Philippine Islands. _General Conclusions as to the Neotropical Insect-fauna._--Looking at the insects of the Neotropical region as a whole, we are struck with the vast amount of specialty they present; and, considering how many causes there are which must lead to the dispersal of insects, the number of its groups which are scattered {19}over the globe is not nearly so great as we might expect. This points to a long period of isolation, during which the various forms of life have acted and reacted on each other, leading to such a complex yet harmoniously-balanced result as to defy the competition of the chance immigrants that from time to time must have arrived. This is quite in accordance with the very high antiquity we have shown most insect-forms to possess; and it is no doubt owing to this antiquity, that such a complete diversity of _generic_ forms has been here brought about, without any important deviation from the great _family_ types which prevail over the rest of the globe.