THE CATERPILLAR AND THE MOTH
to live under trying circumstances she grants it some safeguard against destruction.
The web-spinning habit is one which, as we shall see, these caterpillars will develop to a much greater extent later in their lives, for our little acquaintances are young tent caterpillars. They are round most often among woodland trees, on the chokecherry and the wild black cherry. But they commonly infest apple trees in the orchards, and for this reason their species has been named the apple-tree tent caterpillar, to distinguish it from
Fig. 143. Young tent caterpillars on the egg mass from which they have just hatched. (1¼ times natural size)
related forms that do not commonly inhabit cultivated fruit trees. The scientific name is Malacosoma americana.
The egg masses of the tent caterpillar moths are not hard to find at this season. They are generally placed near the tips of the twigs, which they appear to surround, and being of the same brownish color as the bark, they look like swollen parts of the twigs themselves (Plate 14 A, Fig. 144 A). Most of them are five-eighths to seven-eighths of an inch in length and almost half of this in width, but they vary in thickness with the diameter of the twig. A closer inspection shows that the mass really clasps the twig, or incloses it like a thick jacket lapped clear around. In form the masses are usually symmetrical, tapering at each end, but some are of irregular shapes, and those that have been placed at a forking or against a bud have one end enlarged.
The greater part of an egg mass consists of the covering material, which is a brittle, filmy substance like dry mucilage. Some of it is often broken away, and some-
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