F. Sr. CAMPBELL — OBSERVATIONS ON SPIDERS. 43 



noronant soon seizes this witli its foi-e-loa:s, runs up the thread, and 

 is wafted away to a fresh hunting-ground.* The distance to 

 whieh they are cariied varies much, and Darwin f mentions that 

 the rigging of the " Beagle," when sixty miles from land, was one 

 morning covered with thousands of young and old spiders of both 

 sexes. ]t is owing to such aerial excursions, and also to the 

 practice of some spiders always to trail a thread after them, that 

 at certain seasons of the year, when the weather is favourable, 

 we see so much gossamer. 



As soon as the young spiders are separated from the rest of the 

 brood, they commence to obtain their food according to the habits 

 of their species, whether by webs, as the Kpeirid?e, Theridiidoe, etc., 

 or by fleetness of foot, or ambuscade, as the Lycosidae, Drassidoe, 

 Dysderida?, and Salticidoe, etc. Salticus scenicus has already 

 been mentioned as springing on its prey, but before doing so it 

 attaches its thi-ead to the place from which it starts, thus making a 

 careful provision against a fall. Under its feet, as is the case with 

 many spiders, are pads of stiff bristles which end in a bulbous 

 point. These must be of great service in its spring. 



There is an almost endless variety of webs, from that of the so- 

 called cobwebs in our houses to the beautiful regular snare of the 

 Epeiridae (garden spiders). The former, if preserved from dust and 

 smoke, retain for years their original pearly lustre. The first more 

 or less horizontal line which forms the foundation of the web of 

 the Epeira diadema is drawn from the spinnerets by a light 

 current of air as just described, the spider remaining motionless, 

 apparently waiting to feel the decreased tension as the thread 

 becomes entangled with some fixed object, when it securely fastens 

 the ends. I More or less parallel to this it similarly obtains 

 another. Walking then to some ])oint on the upper thread, it there 

 fixes a third thread, and drops down to the second, and securely 

 attaches the two. It then proceeds to about the centre of the 

 last thread and there fastens another, which it trails along until it 

 reaches some point on the first, to the right or left of the perpen- 

 dicular thread. There the spider draws the loose thread tight, and 

 fastens it. It is thus that all the radii are spun, care being taken 

 that they are arranged so as to keep the whole structure compact 

 and tight. The spider then commences from the centre of its 

 snare to trail a spiral, the lines of which are much farther apart 

 than those seen in the finished web. If we touch this thread we 

 find it is non-adhesive. On reaching the circumference, the spider 

 spins the permanent spiral, making use of the first as a bridge over 

 the distances between the radii, and bites away those parts of it 

 which are no longer required for this pui-pose. The spider thus 

 continues, until it is not far from the centre, when it leaves un- 



* This habit is persistent in some small species. 



t ' Xaturalist's Voyage round the World.' 



X This can easily be seen by placing an Epeira on a stick, standing perpendicu- 

 larly in a pail of water, and opening the door and window of the room so as to 

 cause a drausrht. 



