McCook has given some interesting notes of his own observations on aeronautic spiders. He followed an Attid spider fifty feet till it was carried upward out of sight in a current of air. A Lycosid disappeared in the same way after being followed—at a run—for a hundred feet. The largest Epeirid he ever saw taking flight was “the size of a marrowfat pea, say one-fourth of an inch long. After having floated over a field and above a hedge-row, it crossed a road and anchored upon the top of a young tree.” But perhaps his most interesting observation was on the ability of spiders to control in some measure the duration of their flight by reefing their sails if they wish to descend, for he saw a ballooning spider collecting some of the streamers into a ball of silk which accumulated near its mouth as it gradually sank to earth. The phenomenon known as “gossamer” has puzzled people for centuries, and English poetical literature is full of allusions to it. Chaucer classes it with “ebbe and floud” as an unsolved riddle, and Spenser, Quarles and Thomson all make mention of it, generally embodying the popular belief that it somehow had its origin in dew. “Scorchèd deaw” Spenser calls it, while Thomson’s expression is “dew evaporate.” The phenomenon in question is the occasional appearance of vast numbers of silken flakes which fill the air, and which in some recorded instances extend over many square miles and to a height of several hundred feet. Our observations will have given a clue to its origin which is entirely attributable to spiders, and in large measure to their ballooning habit, though no doubt reinforced by a large quantity of silk spun for other purposes and caught up into the air by the breeze. For a vivid account of such a shower the reader is referred to Letter LXV of White’s _Natural History of Selborne_, and Darwin in his _Naturalist’s Voyage_ (Chap. VIII) records a case of the “gossamer spider” descending in multitudes on the “Beagle” when sixty miles from land. In the ballooning habit we have the probable explanation of the wide distribution of certain species of spiders which seem at first exceedingly ill adapted for covering large distances. The Huntsman Spider, _Heteropoda venatorius_, is practically cosmopolitan in tropical and sub-tropical regions and the usual view has been that ships have conveyed it from port to port. McCook, however, gives several reasons for believing that the trade winds have much more to do with the matter, and this may well be the case, though both agencies have doubtless been at work.