Wherever there is a river, many-coloured armies, bivouacked amidst its various shoals and reefs, sit sucking water through, the moist particles of the sand, whilst others, in even greater numbers, pass and repass from one bank to another, making, however wide the waterway, an aerial fluttering bridge. Other butterflies, also denizens of the great Brazilian or Central American forests, have broad white wings, shot with a satiny lustre, whilst those of yet another are like glass, with one opaque spot of violet and blue, in the midst of each of them. In flight this spot is the only part that can be seen, and it looks, Bates tells us, “like the wandering petal of a flower.”[113] There are swallow-tailed butterflies, too, whose livery of deep, soft green, and deeper velvet black, set off with roseate hues, is amongst the richest of all—“rich, not gaudy,” so at least I should term it, for I have seen it, putting flowers to shame, on the lower slopes of the Himalayas. Here these butterflies—double the size of our _Machaon_, and of another shape, with racquet-rather than swallow-tails, flew on the open hillside, courting the sun, but in Brazil they keep to the forest depths, where, like Una, they “make a sunshine in the shady place.” The butterflies of South America are almost rivalled—quite they cannot be—by those of the Malay Archipelago. Here we have the great Bird-winged Butterfly, discovered by Dr. Wallace, who calls it “elegant,” and bestows upon it a name (_Ornithoptera Brookeana_) which is not quite that.[114] However, “What’s in a name? That which we call a _Brookeana_,” etc.—we must reverse the proposition. There is no describing such a creature—at least, not convincingly. Suffice it to say that its wings “almost resemble those of a sphinx moth in shape,” and are deep, velvety black, but lit up with a band of green feather-like markings, so brilliant and lovely that they reminded its discoverer “of the wing-coverts of the Mexican trogon laid upon velvet”[114]—and that for anyone who has seen a trogon, even stuffed and dried, is to say enough. Besides this adornment the great _Brookeana_ has “a broad neck-collar of vivid crimson and a few delicate white touches on the outer margins of the hind wings.”[114] Another _Ornithoptera_ without the _Brookeana_ is “the largest, the most perfect, and the most beautiful of butterflies.” The two last, however, are matter of opinion, and I should think myself that a _Morpho_ with its azure wings, sometimes seven inches across, and flashing a quarter of a mile away, would run—or fly—it hard. Then there is a yet more gorgeous species of “Bird-winged Butterfly,” with wings equalling or even exceeding the _Morpho’s_ in expanse, whose ample surface is divided between flame-like orange and a black so deep, rich, and velvety that it seems to glow—“the pride of the Eastern tropics, one of the most gorgeously coloured butterflies in the world.”[115]