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supply the Indians with the greater part of their animal food, and are at all times more plentiful, and easier to be obtained, than birds or game from the forest.
During my residence on the Rio Negro I carefully figured and described every species I met with ; and at the time I left fresh ones were every day occurring. The soft-finned fishes are much the most numerous, and comprise some of the best kinds of food. Of the Siluridce I obtained fifty-one species, of Serrasalmo twenty-four, of Chalceus twenty-six, of Gymnotas ten, and of spinous-finned fishes (Acanthopterygid) forty-two. Of all kinds of fishes I found two hundred and five species in the Rio Negro alone, and these, I am sure, are but a small portion of what exist there. Being a black-water river, most of its fishes are different from those found in the Amazon. In fact, in every small river, and in different parts of the same river, distinct kinds are found. The greater part of those which inhabit the Upper Rio Negro are not found near its mouth, where there are many other kinds equally unknown in the clearer, darker, and probably colder waters of its higher branches. From the number of new fishes constantly found in every fresh locality and in every fisherman's basket, we may estimate that at least five hundred species exist in the Rio Negro and its tributary streams. The number in the whole valley of the Amazon it is impossible to estimate with any approach to accuracy.
D. Insects.
To describe the countless tribes of insects that swarm in the dense forests of the Amazon would require volumes. In no country in the world is there more variety and beauty ; nowhere are there species of larger size or of more brilliant colours. Here are found the extraordinary harlequin-beetle, the gigantic Prioni and Dynastes ; but these are exceptions to the great mass of the Cokoptera, which, though in immense variety, are of small size and of little brilliancy of colour, offering a great contrast to the generally large-sized and gorgeous species of tropical Africa, India, and Australia. In the other orders the same rule holds good, except in the Hymenoptera, which con- tain many gigantic and handsome species. It is in the lovely
