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and Trigonopeltastes (6 sp.), allied to the European Trichius. The non-peculiar genera are, Stethodesma, of which half the species are African and half tropical American; and Euphoria, confined to America both North and South.
Buprestidæ.-In this fine group the Neotropical region is tolerably rich, having examples of 39 genera, 18 of which are peculiar to it. Of these, the most extensive are Conognatha and Halecia, which have a wide range over most parts of the region; and Dactylozodes, confined to the south temperate zone. Of important genera which range beyond the region, Dicerca is mainly Nearctic and Palæarctic; Cinyra has a species in North America and one in Australia; Curis is divided between Chili and Australia ; the Australian genus Stigmodera has a species in Chili; Polycesta has a species in Madagascar, two in the Mediterranean region, and a few in North America ; Acherusia is divided between Australia and Brazil ; Ptosima has one species in south temperate America, the rest widely scattered from North America to the Philippines ; Actenodes has a single species in North America and another in West Africa ; Colobogaster has two in West Africa, one in Java, and one in the Moluccas. The relations of South America and Australia as indicated by these insects has already been sufficiently noticed under the latter region.
Longicornia.—The Neotropical Longicorn Coleoptera are overwhelming in their numbers and variety, their singularity and their beauty. In the recent Catalogue of Gemminger and Harold, it is credited with 516 genera, 489 of which are peculiar to it; while it has only 5 genera in common (exclusively) with the Nearctic, and 4 (in the same way) with the Australian region. Only the more important genera can be here referred to, under the three great families into which these insects are divided.
The Prionidæ are excessively numerous, being grouped in 64 genera, more than double the number possessed by any other region; and 61 of these are peculiar. The three, common to other regions, are, Parandra and Mallodon, which are widely distributed ; and Ergates, found also in California and Europe. The most remarkable genera are, the magnificently-coloured Psalidognathus and Pyrodes; the large and strangely marked Macrodontia; and Titanus, the largest insect of the entire family.
Of the Cerambycidæ there are 233 genera, exceeding by onehalf, 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 Toniotes (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 ; A pomecyna 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 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.
The Neotropical region is probably the richest on the globe in Terrestrial Mollusca, but this is owing, not to any extreme productiveness of the equatorial parts of the continent, where almost all other forms of life are so largely developed, but to the altogether exceptional riches of the West India Islands. The most recent estimates show that the Antilles contain more species of land shells than all the rest of the region, and almost exactly as many as all continental America, north and south.
Mr. Thomas Bland, who has long studied American land shells, points out a remarkable difference in the distribution of the Operculated and Inoperculated groups, the former being predominant on the islands, the latter on the continent. The Antilles possess over 600 species of Operculata, to about 150 on the whole American continent, the genera being as 22 to 14. Of Inoperculata the Antilles have 740, the Continent 1,250, the genera being 18 and 22. The proportions of the two groups in each country are, therefore:
West India Islands.
737 The extensive family of the Helicidæ is represented by 22 genera, of which 6 are peculiar. Spiraxis is confined to Central America and the Antilles; Stenopus and Sagda are Antillean only; Orthalicus, Macroceramus, and Bulimulus have a wider range, the last two extending into the southern United
States. Important and characteristic genera are, Glandina, in all the tropical parts of the region; Cylindrella, in Central America and the Antilles ; Bulimus, containing many large and handsome species in South America; Stenogyra, widely spread in the tropics; and Streptaxis, in Tropical South America.
Among the Operculata, the Aciculidæ are mostly Antillean, two genera being peculiar there, and one, Truncatella, of wide distribution, but most abundant in the West Indian Islands. The Cyclostomidæ are represented by 15 genera, 9 being peculiar to the region, and 5 of these (belonging to the subfamily Licinidae) to the Antilles only. Of these peculiar genera Cistula and Chondropoma are the most important, ranging over all the tropical parts of the region. Other important genera are Cyclotus and Megalomastoma; while Cyclophorus also occurs all over the region. The Helicinidæ are mostly Neotropical, six out of the seven genera being found here, and four are peculiar. Stoastoma, is one of the largest genera; and, with Trochatella and Alcadia, is confined to the Antilles, while the wide-spread Helicina is most abundant there.
The Limacidæ, or Old World slugs, are absent from the region, their place being taken by the allied family, Oncidiadæ.
Marine Shells.—We go out of our usual course to say a few words about the marine shells of this region, because their distribution on the two sides of the continent is important, as an indication of the former separation of North and South America, and the connection of the Atlantic and Pacific Oceans. It was once thought that no species of shells were common to the two sides of the Central American Isthmus, and Dr. Mörch still holds that opinion; but Dr. Philip Carpenter, who has paid special attention to the subject, considers that there are at least 35 species absolutely identical, while as many others are so close that they may be only varieties. Nearly 70 others are distinct but representative species. The genera of marine mollusca are very largely common to the east and west coasts, more than 40 being so named in the lists published by Mr. Woodward. The West Indian Islands being a rich shell district, produce a number of peculiar forms, and the west coast of
genera of shells.
South America is, to some extent, peopled by Oriental and Pacific
of shells. On the west coast there is hardly any coral, while on the east it is abundant, showing a difference of physical conditions that must have greatly influenced the development of mollusca. When these various counteracting influences are taken into consideration, the identity or close affinity of about 140 species and 40 genera on the two sides of the Isthmus of Panama becomes very important; and, combined with the fact of 48 species of fish (or 30 per cent of those known) being identical on the adjacent coasts of the two oceans (as determined by Dr. Günther), render it probable that Central America has been partially submerged up to comparatively recent geological times. Yet another proof of this former union of two oceans is to be found in the fossil corals of the Antilles of the Miocene age, which Dr. Duncan finds to be more allied to existing Pacific forms, than to those of the Atlantic or even of the Caribbean Sea.
In the concluding part of this work devoted to geographical zoology, the sub-regions are arranged in the order best adapted to exhibit them in a tabular form, and to show the affinities of the several regions ; but for our present purpose it will be best to take first in order that which is the most important and most extensive, and which exhibits all the peculiar characteristics of the region in their fullest development. We begin therefore with our second division,
II. Tropical South-America, or the Brazilian Sub-region. This extensive district may be defined as consisting of all the tropical forest-region of South America, including all the open plains and pasture lands, surrounded by, or intimately associated with, the forests. Its central mass consists of the great forestplain of the Amazons, extending from Paranaiba on the north coast of Brazil (long. 42° W.) to Zamora, in the province of Loja (lat. 4° S., long. 79° W.), high up in the Andes, on the west ;a distance in a straight line of more than 2,500 English miles,