THE CATERPILLAR AND THE MOTH
taches the thread as far back as it can reach, then runs forward a few paces and repeats the movement, sometimes on the same side, sometimes on the other. The direction in which the thread is carried, however, is a haphazard one, depending on the obstruction the spinner meets from others working in the same manner. Among the crowd of weavers there are always a few individuals that are not working, though they are just as active as the others.
Fig. 148. Mature tent caterpillars. (Natural size)
These are running back and forth over the surface of the tent, like boarders impatiently awaiting the sound of the dinner bell. Perhaps they are individuals that have finished their work by exhausting their supply of silk.
At last the signal for dinner is sounded. It is heard by the caterpillars, though it is not audible to an outsider. A few respond at first and start off on one of the branches leading from the tent. Others follow, and presently a column is marching outward, usually keeping to the well-marked paths of silk till the distant branches are reached. Here the line breaks up into
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