On my first tramp each season in the tropical jungle, I see the legionary army ants hastening on their way to battle, and the leaf-cutters plodding along, with chlorophyll hods over their shoulders, exactly as they did last year, and the year preceding, and probably a hundred thousand years before that. The Colony Egos of army and leaf-cutters may quite reasonably be classified according to Kingdom. The former, with carnivorous, voracious, nervous, vitally active members, seems an intangible, animal-like organism; while the stolid, vegetarian, unemotional, weather-swung Attas, resemble the flowing sap of the food on which they subsist--vegetable. Yet, whatever the simile, the net of unconscious precedent is too closely drawn, the mesh of instinct is too fine to hope for any initiative. This was manifested by the most significant and spectacular occurrence I have ever observed in the world of insects. One year and a half ago I studied and reported upon, a nest of Ecitons or army ants.[3] Now, eighteen months later, apparently the same army appeared and made a similar nest of their own bodies, in the identical spot near the door of the outhouse, where I had found them before. Again we had to break up the temporary colony, and killed about three-quarters of the colony with various deadly chemicals. [Footnote 3: See page 58.] In spite of all the tremendous slaughter, the Ecitons, in late afternoon, raided a small colony of Wasps-of-the-Painted-Nest. These little chaps construct a round, sub-leaf carton-home, as large as a golf ball, which carries out all the requirements of counter shading and of ruptive markings. The flattened, shadowed under surface was white, and most of the sloping walls dark brown, down which extended eight white lines, following the veins of the leaf overhead. The side close to the stem of the leaf, and consequently always in deep shadow, was pure white. The eaves catching high lights were black. All this marvelous merging with leaf tones went for naught when once an advance Eciton scout located the nest. As the deadly mob approached, the wasplets themselves seemed to realize the futility of offering battle, and the entire colony of forty-four gathered in a forlorn group on a neighboring leaf, while their little castle was rifled--larvæ and pupæ torn from their cells and rushed down the stems to the chaos which was raging in Eciton's own home. The wasps could guard against optical discovery, but the blind Ecitons had senses which transcended vision, if not even scent. Late that night, our lanterns showed the remnants of the Eciton army wandering aimlessly about, making near approach impossible, but apparently lacking any definite concerted action.