“In the nomadic phase a new bivouac is formed at the end of each day of raiding. In the advanced and most complicated stages of raiding in the afternoon, caches of booty tend to be formed at each busy junction of raiding trails, increasing in size as more and more ants are knocked around and forced out of traffic. As darkness comes and raiding ceases such clusters grow. Several hanging clusters start from elevated ceilings. As each new cluster begins, the initial slender hanging threads may become ropes which extend to the ground. As the ropes continue to grow they are joined together into a single columnar mass. “At first this mass is small in diameter, but as more and more ants pour into it the wall spreads outwards from the center and so a symmetrical cylinder results.” In the tropical environment of the army ants some sort of air conditioning is necessary for comfortable living—perhaps, with this particular species, for any living at all. It has been well developed during the more than 50 million years the insects have been on earth. Says Dr. Schneirla: “The interior of the bivouac, where the brood is sheltered and the single colony queen rests, offers an impressively stable environment to these more susceptible members of the community as well as a central resting place for the worker population. The hanging cluster traps a cubic area for atmosphere which does not reach the extremes of temperature and dryness attained by the general forest environment, but in general is somewhat warmer and more humid at night and somewhat cooler and dryer during the day. “This result is achieved mainly as a result of worker behavior. Workers cluster more closely together at night in reaction to the lower temperature of the forest at the time. The bivouac walls become tighter and thus better conserve heat produced internally by the brood. “Conversely, after dawn, when increasing light excites growing numbers of ants to leave the bivouac, as the raid grows, this wall thins out, usually develops small apertures, and is undercut at the bottom. The effect is to increase internal air circulation as well as to cool the atmosphere of the interior through evaporation, so that the internal temperature of the bivouac does not rise to the height reached at midday in the environs. “The incubation properties of the bivouac represent an important factor in echelon life, for with less regular atmospheric conditions in the nest the stages of brood development could not have their typical regularity in timing.” _Uganda’s Miniature Dinosaur_ A grotesque creature abundant in the Kishasha Valley of Uganda is the three-horned chameleon. It grows to a length exceeding twelve inches and the males look like miniature versions of the ancient dinosaur monster, triceratops. Three curious horns, an inch to an inch-and-a-half in length, protrude from the nose and between the eyes of males.