big game, we have been largely forced to rely either on native report, in which acutely accurate observation is invariably mixed with wild fable, or else on the chance remarks of travellers or mere sportsmen, who had not the training to make them understand even what it was desirable to observe.  Nowadays there is a growing proportion of big-game hunters, of sportsmen, who are of the Schilling, Selous, and Shiras type.  These men do work of capital value for science.  The mere big-game butcher is tending to disappear as a type.  On the other hand, the big-game hunter who is a good observer, a good field naturalist, occupies at present a more important position than ever before, and it is now recognized that he can do work which the closest naturalist cannot do.  The big-game hunter of this type and the outdoors, faunal naturalist, the student of the life-histories of big mammals, have open to them in South America a wonderful field in which to work.

The fire-ants, of which I have above spoken, are generally found on a species of small tree or sapling, with a greenish trunk.  They bend the whole body as they bite, the tail and head being thrust downward.  A few seconds after the bite the poison causes considerable pain; later it may make a tiny festering sore.  There is certainly the most extraordinary diversity in the traits by which nature achieves the perpetuation of species.  Among the warrior and predaceous insects the prowess is in some cases of such type as to render the possessor practically immune from danger.  In other cases the condition of its exercise may normally be the sacrifice of the life of the possessor.  There are wasps that prey on formidable fighting spiders, which yet instinctively so handle themselves that the prey practically never succeeds in either defending itself or retaliating, being captured and paralyzed with unerring efficiency and with entire security to the wasp.  The wasp’s safety is absolute.  On the other hand, these fighting ants, including the soldiers even among the termites, are frantically eager for a success which generally means their annihilation; the condition of their efficiency is absolute indifference to their own security.  Probably the majority of the ants that actually lay hold on a foe suffer death in consequence; certainly they not merely run the risk of but eagerly invite death.

The following day we descended the Sao Lourenco to its junction with the Paraguay, and once more began the ascent of the latter.  At one cattle-ranch where we stopped, the troupials, or big black and yellow orioles, had built a large colony of their nests on a dead tree near the primitive little ranch-house.  The birds were breeding; the old ones were feeding the young.  In this neighborhood the naturalists found many birds that were new to them, including a tiny woodpecker no bigger than a ruby-crowned kinglet.  They had collected two night monkeys—­nocturnal monkeys, not as agile as the ordinary monkey; these two were found at dawn, having stayed out too late.