We watch the autumn passing of birds with regret, but when the bluebirds warble their way southward we are cheered with the hope and the knowledge that some, at least, will return. Here, vast stretches of country, perhaps all Guiana, and how much of Brazil and Venezuela no one knows, poured forth a steady stream of yellow and orange butterflies. They were very beautiful and they danced and flickered in the sunlight, but this was no temporary shifting to a pleasanter clime or a land of more abundant flowers, but a migration in the grim old sense which Cicero loved, _non dubitat_ ... _migrare de vita_. No butterfly ever turned back, or circled again to the glade, with its yellow cassia blooms where he had spent his caterpillarhood. Nor did he fly toward the north star or the sunset, but between the two. Twelve years before, as I passed up the Essequibo and the Cuyuni, I noticed hundreds of yellow butterflies each true to his little compass variation of NNW. There are times and places in Guiana where emigrating butterflies turn to the north or the south; sometimes for days at a time, but sooner or later the eddies straighten out, their little flotillas cease tacking, and all swing again NNW. To-day the last of the migration stragglers of the year--perhaps the fiftieth great-grandsons of those others--held true to the Catopsilian lodestone. My masculine pronouns are intentional, for of all the thousands and tens of thousands of migrants, all, as far as I know, were males. Catch a dozen yellows in a jungle glade and the sexes may be equal. But the irresistible maelstrom impels only the males. Whence they come or why they go is as utterly unknown to us as why the females are immune. Once, from the deck of a steamer, far off the Guiana coast, I saw hosts of these same great saffron-wings flying well above the water, headed for the open sea. Behind them were sheltering fronds, nectar, soft winds, mates; before were corroding salt, rising waves, lowering clouds, a storm imminent. Their course was NNW, they sailed under sealed orders, their port was Death. Looking out over the great expanse of the Mazaruni, the fluttering insects were usually rather evenly distributed, each with a few yards of clear space about it, but very rarely--I have seen it only twice--a new force became operative. Not only were the little volant beings siphoned up in untold numbers from their normal life of sleeping, feeding, dancing about their mates, but they were blindly poured into an invisible artery, down which they flowed in close association, _véritables corpuscules de papillons_, almost touching, forming a bending ribbon, winding its way seaward, with here and there a temporary fraying out of eddying wings. It seemed like a wayward cloud still stained with last night's sunset yellow, which had set out on its own path over rivers and jungles to join the sea mists beyond the uttermost trees.