But, as far as my personal observation goes, the green tree-ants do not effect any alteration in the superficial appearance nor destroy the structure of leaves, nor employ any physical power at the first stages of the construction of a habitation. The process by which a leaf is curled extends over several days, and but few take part in it. Half a dozen ants may be seen perpetually engaged in, apparently, an unmethodical but extremely minute and critical inspection of the rhachis and the nerves or ribs of the leaf. Days pass. The ants are there all the time, examining the leaf and communicating with each other whensoever they meet. Imperceptibly the leaf begins to curl. The ants continue to make mesmeric passes over the nerves with ever-waving antennae. In accordance with the will and the design of the architects, who merely stand by and gesticulate, the opposite margins approach, or the apex curls towards the base, or towards one of the sides to form a miniature funnel. When the extremities are so close that the intervening space may be spanned, threads of white gossamer are laced across, and the slack being taken up by degrees, in a few days a cosy pocket with closely-fitting seams is completed. How is this folding of the leaf accomplished? A theory which presents itself is that the ants eject some active chemical principle into certain of the cells of the leaf tissue, and that the stimulus is transmitted by excitation from cell to cell, bringing about a general and uniform contraction without destroying the vitality of the leaf. Further, by the application of the injection to specific cells the ants convey impulses to specific nerves, causing the leaf to curl longitudinally or laterally, or at any angle they design. The poison that a single ant injects into the neck of a brawny man so affects his nervous system that he twists and writhes and stamps his feet with energy sufficient to destroy millions of the species. Maybe a slightly different compound is reserved for vegetable substances, which can offer only a flabby sort of remonstrance. If this theory be supported on investigation, surely the green tree-ant will deserve to be catalogued among creatures who have solved labour-saving problems--who employ consciousness, if not rational thought, to compensate for physical frailty. This theory is applicable to the manipulation of a single leaf only, and of a leaf of considerable size. Yet these feeble folk more frequently take up their quarters in trees bearing small leaves, of which scores are embodied in a mansion. Immense and concentrated exertion is necessary to draw far-flung branchlets and leaves together, and the feverish host accomplishes a seemingly impossible feat by an organised combination of engineering with co-operative labour. Spaces between leaves and twigs four and five inches wide are bridged by chains of ants--each individual clasping with its mandibles above the abdominal