1. That the imitative species occur in the same area and occupy the same station as the imitated. 2. That the imitators are always the more defenceless. 3. That the imitators are also less numerous in individuals. 4. That the imitators differ from the bulk of their allies. 5. That the imitation, however minute, is external and visible only, never extending to internal characters or to such as do not affect the external appearance.
There are plenty of examples of this phenomenon, such as the hornet-like moths and bee-like flies of our own country, and many other instances will be found in these pages. One discovered in tropical America by Mr. W.L. Sclater would have much delighted Belt had he come across it. In that region of the world the leaf-cutting ants present a very characteristic appearance as the column proceeds homewards, each ant carrying a piece of leaf held vertically in its jaws; and a homopterous insect has been found that faithfully resembles an ant bearing its burden. The latter is suggested by the thin compressed green body of the insect, and its profile is precisely like that of the jagged edge of the fragment of leaf held over the back of the ant.
Of all the Nicaraguan fauna, judging from the narrative, the ants occupy the most prominent position. Both indoors and out they are ever in evidence. Belt describes the foraging ants, which do not make regular nests of their own, but attack those of other species and prey upon every killable living thing that comes in their way; the leaf-cutting ants, whose attacks upon his garden were repelled with so much difficulty; standing armies of ants maintained by certain trees for their protection, and many other kinds, some of which kept his attention constantly on the stretch. Much space is devoted to their habits and wonderful instincts, amounting in many cases, so Belt considered, to as clear an evidence of reasoning intelligence as can be claimed for man himself. Indeed, after reading the account of their freeing of an imprisoned comrade and their grappling with problems arising out of such modern inventions as carbolic acid and tramways, we need not feel surprised if an observer accustomed to scrutinise the animal world so closely feels sceptical on the subject of "instinct" viewed as a mysterious entity antithetically opposed to "reason" and supposed to act as its substitute in the lower orders.
In reference to their methods of obtaining food, ants have been classified as hunting, pastoral, and agricultural, "three types," as Lord Avebury remarks, "offering a curious analogy to the three great phases in the history of human development." As regards their social condition they differ from mankind in having successfully established communism. At the present day all the social hymenoptera possess a unique interest on account of their working-order or neuters. These, as is well-known, are females whose normal development has been checked. Are we to assume that "once upon a time" a woman's rights movement sprang up in bee-hives and ant-hills which ended in reducing the males to a very unimportant position and in limiting the number of the fully developed females? Are we to expect that the "strong-minded" women arising among us are the forerunners of a "neuter" order and the heralds of a corresponding change in human society?
"It is full of theories," says the author, writing of his book; modestly adding, "I trust not unsupported by facts." And so naturally does he dovetail the two together that the theories often seem portions of the facts. On all kinds of subjects suggestive reasons are proposed:—why the scarlet-runners which flowered so profusely in his garden never produced a single pod; why the banana and sugar-cane are probably not indigenous to America; why gold veins grow poorer as they descend into the earth; why whirlwinds rotate in opposite directions in the two hemispheres; why the earthenware vessels of the Indians are rounded at the bottom and require to be placed in a little stand—on all the varied matters that come under his observant eyes he has something interesting to say. You learn how the natives obtain sugar, palm-wine, and rubber; what is the use of the toucan's huge beak, and how plants secure the fertilisation of their flowers. You watch the tricks of the monkey, the humming-bird's courtship, the lying in wait of the alligator, and all the ceaseless activity of the forest—that forest so monotonous in its general features, but fascinating beyond measure when the varied life-histories working out within it are realised—and you share in the keen joy of the naturalist who has written with such simple eloquence of the beauty, the wonder, and the mystery of the natural world.
A.B.
The following is a list of the works of Thomas Belt:—
An inquiry into the Origin of Whirlwinds,
Philosophical Magazine volume 17 1859 pages 47-53.
Mineral Veins: an Inquiry into their Origin
founded on a Study of the Auriferous Quartz Veins of Australia,
London 1861.
On some Recent Movements of the Earth's Surface
and their Geological Bearings [1863] Nova Scotian Institute of
Natural Science Proceedings and Transactions
volume 1 part 1 1867 pages 19-30.
List of Butterflies observed in the Neighbourhood of Halifax,
Nova Scotia [1863] Nova Scotian Institute of Natural Science
Proceedings and Transactions volume 2 part 1 1867 pages 87-92.
On the Formation and Preservation of Lakes by Ice Action,
Geological Society Quarterly Journal volume 20 1864 pages 463-465,
Philosophical Magazine volume 28 1864 page 323,
Nova Scotian Institute of Natural Science Proceedings and
Transactions volume 2 part 3 1867 page 70.
The Glacial Period in North America [1866] Nova Scotian Institute
of Natural Science Proceedings and Transactions
volume 2 part 4 1867 pages 91-106.
On some New Trilobites from the Upper Cambrian Rocks of North Wales,
Geological Magazine volume 4 1867 pages 294-295.
On the "Lingula Flags" or "Festiniog Group" are the
Dolgelly District, Geological Magazine
volume 4 1867 pages 493-495, 536-543; volume 5 1868 pages 5-11.
The Naturalist in Nicaragua, London 1874 2nd edition
revised and corrected 1888.
Glacial Phenomena in Nicaragua, American Journal of Science
volume 7 1874 pages 594-595.
An Examination of the Theories that have been proposed to account
for the Climate of the Glacial Period,
Journal of Science volume 4 1874 pages 421-464.
The Steppes of Siberia, Geological Society Quarterly Journal
volume 30 1874 pages 490-498,
Geological Magazine Decade 2 volume 1 1874 pages 423-424.
The Glacial Period, Nature volume 10 1874 pages 25-26.
Niagara: Glacial and Post-Glacial Phenomena,
Journal of Science volume 5 1875 pages 135-156.
The Drift of Devon and Cornwall: its Origin, Correlation with
that of the South-West of England, and Place in the Glacial
Series, Geological Society Quarterly Journal
volume 32 1876 pages 80-90;
Geological Magazine volume 2 1875 pages 622-624,
Philosophical Magazine volume 1 1876 pages 159-161.
On the Geological Age of the Deposits containing Flint Implements
at Hoxne, in Suffolk, and the Relation that Palaeolithic Man
bore to the Glacial Period,
Journal of Science volume 6 1876 pages 289-304.
On the First Stages of the Glacial Period in Norfolk and Suffolk,
Geological Magazine volume 4 1877 pages 156-158.
The Steppes of Southern Russia, Geological Society Quarterly Journal
volume 33 1877 pages 843-862;
Philosophical Magazine volume 4 1877 pages 151-152.
On the Loess of the Rhine and the Danube,
Journal of Science volume 7 1877 pages 67-90.
The Glacial Period in the Southern Hemisphere,
Journal of Science volume 7 1877 pages 326-353.
Quartzite Implements at Brandon,
Nature volume 16 1877 page 101.
On the Discovery of Stone Implements in Glacial Drift
in North America, Journal of Science volume 8 1878 pages 55-74.
The Superficial Gravels and Clays around Finchley, Ealing,
and Brentford, Journal of Science volume 8 1878 pages 316-360.
Notes on the Discovery of a Human Skull in the Drift near Denver,
Colorado, Proceedings of the American Association for the
Advancement of Science at St. Louis,
Missouri August 1878 volume 27 (1879) pages 298-299.
[The notes within square brackets have been added to this edition by the writer of the Introduction. ]
[Title-page of the First Edition.]