Two other species--Eciton vastator, and Eciton erratica--both of which are blind, move entirely under covered ways in search of promising hunting-grounds. Their arcades are sometimes two hundred yards in length, the grains of earth being taken from the soil over which the column is passing, and fitted together without cement. In this they are distinguished from the covered ways made by the termites, who use a glutinous saliva for cementing their edifices. These blind ecitons build up the side of their convex arcade, and in a wonderful manner contrive so to fit in the key-stones, without allowing the loose uncemented structure to fall to pieces. Whenever a breach is made in any of their covered ways, the workers remain behind to repair the damage, while the soldiers issue forth in a menacing manner, rearing their heads, and snapping their jaws with an expression of fiercest rage and defiance. The above account will give some idea of the vast numbers and varieties of the termites and ants of this region, and of the wonderful way in which Providence has furnished them with the means of sustaining existence, and taking their part in the economy of nature. Science is deeply indebted to Mr Bates, for his persevering efforts and acute observation in making known the varieties and habits of these curious insects. CENTIPEDS--COCKROACHES--FIRE-ANTS. Although the rest of the animal creation is small compared with the creatures of the Eastern world, insects and reptiles attain a size which will vie with those of any portion of the globe. Here we have a centiped nearly a foot in length, with innumerable legs, and two horns or feelers, which it protrudes with the most venomous expression. These animals are not only hideous to look on, but their bite is _very_ painful, though not dangerous. Cockroaches swarm everywhere; but the fire-ant is, for its size, probably the most terrible of created beings. Its bite produces the most acute pain; and where they swarm, on the dry sandy shores of the streams, they frequently compel the natives to desert their villages. Mrs Agassiz mentions having on one occasion hung some towels to dry on the cord of her hammock, and was about to remove them, when suddenly her hand and arm seemed plunged into fire. She dropped the towels as if they were hot coals, which for the moment they literally seemed to be. She then saw that her arm was covered with little brown ants. A native brushed them off in all haste; and an army of them was found passing over the hammock, and out of the window, near which it hung. He said they were on their way somewhere, and if left undisturbed would be gone in an hour or so. INSECTS--FIRE-FLIES.