410 TEXT-BOOK OF ZOOLOGY 



either by chasing it, or suddenly pouncing down on it from an ambush, 

 or capturing it in snares of the most varied construction. The spider's 

 webs which we see in the corners of rooms, stables, lofts, etc., are the 

 work of the Common House Spider (Tegenaria domestica). These 

 webs, which also form the animal's dwelling, are always stretched 

 horizontally, and are funnel-shaped or tubular. 



One species, the Water Spider (Argyroneta aquatica), actually lives 

 in the water, where it chiefly pursues water-slaters (Asellus, which see). 

 The abdomen of this spider has a velvety covering of hairs, and, just as 

 a layer of air remains adherent to a velvet rag dipped in water (see 

 otter), so this spider always carries a large silvery air-bubble down with 

 it below the water. There it spins a dwelling not unlike a small diving- 

 bell, which it anchors by threads to water-plants, and fills with air 

 collected in the aforesaid manner. Thus the animal lives in air in the 

 midst of the water ! 



On sunny days in autumn large numbers of fine threads, the so-called 

 gossamer threads (what other names do they go by ?), may be seen floating 

 about over fields and meadows. On some one or other of these threads, 

 if examined, we shall find a small (young) spider. This aerial vehicle is 

 of the creature's own construction, having been produced in the following 

 manner : Having ascended some elevated spot, such as a clod of earth, 

 the spider spins a few short threads, which are fastened to the ground. 

 These it grasps in order to obtain a firm hold. Next it once more 

 presses the silk glands against the supporting surface, and elevates its 

 abdomen. In this way a thread is formed, which, soon being seized by 

 the wind, is drawn out longer and longer, blown hither and thither, 

 and thrown into tangles, so that finally a small raft is produced. At 

 last the wind lifts both the raft and its maker up into the air, and the 

 aerial journey begins. Perchance the little ship will be stranded 

 agreeably to the wish of its navigator in some spot where the latter 

 may enjoy its winter rest in security, in order in the following year to 

 spread its species. 



In comparison to the spiders of tropical countries, even our largest 

 species are mere dwarfs. The most familiar of these giants is the Bird 

 Spider (Avicularia) of South America, which is covered with hairy fur, 

 and will even kill small birds. 



OTHER ARACHNIDS. 



In addition to the true spiders, numerous other animals of very 

 different structures are classed with the Arachnida. 



