Very likely it was not obvious to the reader why he was recommended to select a particularly calm, sunny autumn day for his study of spider aeronautics; a strong steady breeze might well appear more suitable for the purpose. Yet he would find these operations at a standstill on a windy day, and the best possible conditions are a still warm morning after a spell of cooler weather. The lightest air-currents serve to float the delicate silken threads, and, what is more important, the increase of temperature causes an upward draught which rapidly carries the spider to a useful height where it sails gently away instead of being swept roughly over the surface of the ground. CHAPTER VI AGELENA Before going farther afield, let us investigate one of the spinners of the sheet-webs that are so unpleasantly familiar in the house. We object to them on very obvious grounds, first as evidence of neglect and bad housewifery, and secondly as repulsive objects when covered by accumulations of dust which their firm texture and their durability make inevitable. The common house-spiders belong to the family Agelenidae. It is quite likely that their original home was in a warmer climate where they lived out of doors, but that was long ago, and now they uniformly select buildings of some sort for their operations. They have, however, even in this country, several open-air cousins, and most people know the great sheet-web spider of the hedge-rows, though its name—_Agelena labyrinthica_—may be new to them. Its web consists of a closely woven wide-spreading sheet connected with a tube of even denser material, in the mouth of which the spider may generally be seen lurking, a rather sinister object. If a better view of the animal is desired it is only necessary to agitate the web slightly and the spider runs forward to investigate. It is a large species as British spiders go—about three quarters of an inch in length—with the abdomen rather prettily marked with oblique white streaks. It is very unlike our garden spider in certain points of structure; its body is more elongate and rather rigid, with little play of action between the cephalothorax and the abdomen; its legs are notably long, and so are two of its spinnerets, which can be seen protruding beyond the abdomen as we look down upon it. But we shall gain little information by looking at the completed web, and our best plan is to take the animal home and observe it in captivity. We have prepared for its reception a box about a foot square, with a gauze top and a movable glass front.