Page:Popular Science Monthly Volume 45.djvu/361

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HOMES OF SOCIAL INSECTS.
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moths or other enemies of any size. It is strange that the interior surface of the nest is provided with tubercles, a circumstance that must put the insects to the trouble of gnawing them away each time they add a stage. Probably the same material is again employed in establishing fresh cells and in building the new platform.

A longitudinal section shows the peculiar disposition of the combs. Just as in the spherical nests of Polybia, the highest ones are perfect or almost perfect spheres; but this method of construction is soon found to be too laborious. A nearly globular mass of the brown paper-like substance exists at the top the nucleus, so to speak. The first combs closely surround this, so that they form the best parts of hollow spheres; then come great arcs of circles, followed in regular order by other tiers, their rotundity becoming gradually reduced until the curve of the lower ones is extremely shallow, exactly like the tiers of Tatua, except that they exhibit a trifling convexity on their lower surfaces. They are carried to the common wall and thereto affixed, small spaces being left open here and there between their edges and the envelope. The solid wall at the top is of great thickness (see Fig. 5).

In the nest in the British Museum already described, a quantity of brownish-red honey was found in the upper combs, but hard and dry. Even so long ago as the beginning of the century, Azara, a Spanish officer, who was sent out by his Government to Paraguay to make certain investigations in that country, mentions that a South American wasp which he calls chiguana has the strange habit of hoarding honey. The chiguana of Azara, it would seem, is identical with Polybia scutellaris. At the time of publication Azara's statement was not believed, so opposed was the habit that he claimed for this insect to the known actions of wasps. He and his men ate from the chiguana's store, and it proved deleterious. St. Hilaire, a subsequent traveler, speaks of two South American honey wasps. The honey of one was white and innocuous, that of the other was reddish brown and poisonous. The good honey was in an oval, light-colored nest of thin, papery material, totally different from the paper of Myrapetra, and was observed by Hilaire on a small bush near Uruguay, at a distance of only about a foot from the ground. This wasp has been described as lecheguana. Probably under the term lecheguana, or chiguana, as Azara has it, the inhabitants of America confound many wasps of similar kinds, and it is rather a generic title for all honey wasps than for one species in particular.