Very similar habits obtain among the THERIDIIDAE, or line-weaving spiders, a familiar example of which is the pretty little _Theridion sisyphium_, whose highly-irregular snare may be found on any holly bush during the summer months. [Illustration: FIG. 188.—=A=, _Pardosa_ sp. ♀, with young on the abdomen; =B=, young _Pardosa_ detached; =C=, outline of the Spider with young removed. (From the living specimen.) ] The LYCOSIDAE, or Wolf-spiders, which chase their prey instead of lying quietly in ambush to ensnare it, are exceedingly interesting in their treatment of their young. The cocoon, or bag of eggs, is carried about on all their expeditions, attached beneath the abdomen, or held by the jaws, and the young spiders, on escaping from it, mount on the mother’s back, and indulge vicariously in the pleasures of the chase from this point of vantage. The empty egg-bag is soon discarded, but the brood continues to ride on the mother’s back for about a week, dismounting only to follow her as she enters her little silk-lined retreat in the ground. During this time they appear to require no food, but they at length begin to disperse, the mother gently but firmly removing such individuals as are disposed to trespass upon her maternal solicitude longer than she considers desirable. Many young spiders of various Families proceed immediately to seek new hunting-grounds by the aid of the wind, and become for the time being diminutive aeronauts. This habit was observed by the earliest British araneologist, Martin Lister,[271] as long ago as 1670, and has been alluded to by many writers since his time. The topmost bar of an iron railing in spring or early autumn will generally be found peopled with minute spiders, and if the day be fair and the wind light, the patient observer may be rewarded by a curious and interesting sight. The spider seeks the highest spot available, faces the wind, and straightens its legs and body, standing, so to speak, upon its toes, its abdomen with its spinning tubes being elevated as much as possible. Streamers of silk presently appear from the spinnerets and float gently to leeward on the light current of air. The spider has no power to shoot out a thread of silk to a distance, but it accomplishes the same result indirectly by spinning a little sheet or flocculent mass which is borne away by the breeze. [Illustration: FIG. 189.—Young Spider preparing for an aerial voyage. (After Emerton.) ] When the streaming threads pull with sufficient force the animal casts off, seizes them with its legs, and entrusts itself to the air, whose currents determine the height to which it is carried and the direction of its journey. The duration, however, is not quite beyond the spider’s control, at all events in calm weather, for it can furl its sail at will, hauling in the threads “hand-over-hand,” and rolling them up into a ball with jaws and palps.