They are looper caterpillars, which lift themselves like croquet hoops when they walk, and they can also float across to another tree, hanging on a silken thread.

Eventually, the silken thread will adhere to an object where the young spider will establish its own web.

Other people have taken the metaphor farther by comparing the act of baling out with that of the caterpillar letting itself down to earth by a silken thread.

They also balloon from one tree to another on long silken threads.

They hide in a rolled-up leaf held together by silk and eat it from inside, and they drop down on silken threads if disturbed.