C58 



SPIDER 



A peculiar and highly interesting characteristic of 

 the spiders is their power of making silk, and the 

 varied uses to which this substance is applied. I 

 like the product of the silk-making insects, which is 

 exuded from the iindt>r-lip. that of the spider cmiics 

 from jointed spinnerets situated behind the anus, 

 mast spiders possessing 3 pairs of these appendages. 

 They are conical papillie, surrounded by stiff hrist ! - 

 ami hairs, and dotted at the apex with horny tubes 

 varying from 100 to 1000 in number. The Bilk is 

 secreted as a viscid liquid, which dries and hardens 

 immediately on contact with the air. The silken 

 filaments are very strong and fine, one coming from 

 each tube of the spinnerets, while each line of the 

 spider-web is composed of hundreds or thousands of 

 smaller ones. According to Leuwenhoek it would 

 take 4,000,000 of the tine filaments to make the size 

 of a human hair. The supply of silk seems sufficient 

 to make 6 or 7 webs during the season. 



The sexes of spiders are separate, the males and 

 females living apart. The females are oftenest seen, 

 and are the larger, often considerably so, while their 

 carnivorous instinct leads them frequently to attack 

 and devour the males, even in the reprodiictr 

 son. Spiders ordinarily obtain nutriment by snck- 

 ing the juices of their insect prey, but sometimes 

 swallow the flesh. They can support long fasts, and 

 spend the winter in a torpid state. They are very 

 cleanly in habit, and spend much time in clearing 

 their body and limbs of dust and dirt. They have 

 much ingenuity and jxjrseveranco, and display con- 

 siderable intelligence in adapting themselves to cir- 

 cumstances and in changing the form of the web to 

 suit the locality. 



Nine-tenths of all spiders are included in the fol- 

 lowing families, as named and described by Emerton. 

 The ilygalitbe embrace the largest tropical species. 

 They usually have very hairy and dark bodies, with 

 only two pairs of spinnerets, one pair being very' 

 long, and turned up behind the abdomen. There 

 are four air-sacs under the front of the abdomen, in- 

 stead of two as in other spiders. The mandibles are 

 very large, and work up and down instead of side- 

 ways. Most members of the family belong to tho 

 tropics, but there are some species in the south- 

 western United States. Some of the Mygales are 

 very strong, M. avicularia, the bird-eating spider, 

 being about 3 inches long, while its legs spread over 

 8 or 10 inches. It leaps upon and destroys hum- 

 ming-birds and other small birds. 



The Dy*deritla> form a small family, of which 

 there are few North American species. They are 

 usually found under stones, the legs being drawn 

 up close to the body. They have eyes, and 4 

 breathing-holes, one pair of which leads to branched 

 tubes instead of to sacs. Tho l)i-<i*si<l,r are a largo 

 family whose members vary greatly in shape, color, 

 and habits. They, like the bora, make no webs, 

 but usually live under stones, or in silken tubes on 

 plants. They have small eyes arranged in two rows 

 on the front of the head, and long spinnerets. '1 1m 

 Ayiilenidtr are a tribe of long-legged web-building 

 spiders, of a brown color, and with one pair of spin- 

 longer than the others. They build flat webs 

 with a funnel shaped tube on one Bide, which forms 

 the den in which the spider lies in wait for it 



' are similar to the above, but differ 

 in tho possession of a peculiar spinning organ. This, 

 called the criliellmn, lies in front of the spinner- 

 ets, and has much finer tubes. The threads from 

 it are drawn out and tangled, and are attached to the 

 plain threads of the web, serving to make it more 

 adhesive. 



The Lt/cntidce, or running-spiders, form a numer- 

 ous and interesting family. They live in open 

 places, build no webs, and are very active in their 

 movements, they Laving long legs, of which tho 



' rear pair is the longest. The head is held high, giv- 

 ing an aspect of vigilance to the animal. The name of 

 f.tinily refers to their wolf-like habit of running 

 down their prey. Tho Attii/ip, or jumping spiJi-is, 

 have usually a short body audsquurc head, wit" 

 culiar arrangement of the eyes, there being two largo 

 ones in the middle which give them a look of spe- 

 cial animation. Their legs are short, it being their 

 habit to leap on their prey. Tho Tltmnixitlip, or crab- 

 spiders, have bodies usually flat and widest in tho 

 rear, and somewhat resemble the crab in appear- 

 ance. Tho front two pahs of legs are longer than 

 the rear ones, and are bent in such a manner that 

 the spider can readily move in a narrow cniek. 

 Some walk sideways, like the crabs. They build 

 no webs. 



The T/irri(liid(p form the largest family of tlio 

 spiders. They are generally of small size, with 

 large rounded abdomens and slender legs. They 

 build large webs, whose shapes differ for different 

 species, and rest, head downward, under theM* web-, 

 holding on by their feet. Tho most interesting 

 family of web-builders ore the F.periihr, the makers 

 of tho orb-like, geometrical webs which form at- 

 tractive objects of spider-architecture. The si 

 of this family are largo in size, wi:h short, round 

 abdomens, flat heads, nnd eyes widely separated. 

 The webs are made in lines radiating from a centre, 

 and crossed by adhesive lines wound in a spiial or 

 in concentric circles. Like the last-named family, 

 the Eperidce hang head downward in ihe web, or i;i 

 other cases live in a hole near by, keeping in con- 

 stant communication wi.h the web by tho aid of a 

 connecting line. 



The ordinary belief that spiders nro aggressive 

 and poisonous is based rather on prejudice than fact. 

 If not disturbed, they will not bite, though all spi- 

 ders will bite when cornered. There are few satis- 

 factory instances on record of their biting man, and 

 stories of injury from spider-bites nro mostly erro- 

 neous. The great majority of spiders are undoubt- 

 edly harmless to man, the tarantula, and perhaps mo 

 or two other s]>ecies, being tho only ones that need 

 bo avoided. Fear nnd prejudice-, rather than fact, 

 have given tho spider its b.ul reputation. 



It is by their spinning habits that the spiders nro 

 specially distinguished from other animals, tho silk- 

 en lino, which is principally employed by insects in 

 making a eoeoon, or a nest for their you tip, bcimr 

 applied by tho spider to a considerable variety < f 

 purposes. The spinning instinct is so strong that it 

 is manifested by the young ns soon ns they l:ave left 

 tin- egg, those of certain t-pecies dwelling together 

 in a common web till they are strong enough to 

 build for themselves. Spiders in confinement begin 

 pin at once, and do not seem comfortable till 

 they can go everywhere within their bounds on tho 

 web. As they walk, they diaw out a thread behind 

 them, while 'tho young of many species and tho 

 adults of some small species, use the silken thrend 

 ns a means of flight, emitting sufTcient to support 

 them in the air b\ its buoyancy. It is believed that 

 when they wish to descend they draw in a portion of 

 this flying thread. 



The leaping spiders make another use of the 

 thread. "When springing from n vertical wall on 

 insects, as they frequently do, they always 

 remain attached to the wall by a thrend. nnd are 

 thus drawn back and saved from falling. The water- 

 spider makes a small silken tent on plants beneath 

 the surface. This opens downward, and is filled 

 with nir which its occupant carries down, a bubble 

 at a time. Thus domiciled, it runs about on the 

 water-plants, and catches the minute insects that 

 live upon them. Its hairs keep the water from its 

 skin. Some species that live on land-plants make 

 flat tubes of silk, in which they lie in wait. Others 



