The Flying Horseman by Gustave Aimard

The sun, which had been nearly on the level of the horizon, soon disappeared; his disc was no longer visible through the branches; the evening breeze in fitful gusts agitated the foliage, and the birds rapidly regained their roost for the night. The atmosphere was sensibly refreshed, and though light remained on the plain, the thickets and shrubbery were already shadowed by twilight. The mosquitoes buzzed by myriads over the ponds and lakes, the greenish and stagnant water of which was agitated by the movements of the reptiles. Already some dull growls had troubled the silence of the desert, announcing the awakening of the animals, saluting, on emerging from their secret lairs, the setting of the sun.

The three men were sitting in the underwood, which began to be shrouded in darkness. The Pincheyra had gone to seek his horse, which had been left near those of the gauchos, to feed on the fresh grass and the young roots of trees.