Spiders.] 



MUSEUM OF ANIMATED NATURE. 



331 



these lines, availing themselves of currents of air, 

 which cany them lengthening still, till their float- 

 ing extremity becomes attached to some fixed ob- 

 ject. Experiments made by msulating spiders on a 

 branch or twig surrounded by water seem to prove 

 the truth of this explanation. Generally the Geo- 

 metric spider stations herself in the centre of her 

 web, — watching for prey, but not always — for, 

 as we have repeatedly observed, she often lurks 

 under the shelter of an adjacent leaf, ready to glide 

 along her cordage, like a sailor from the topmast, 

 upon her heedless victim. Fig. 3314 represents the 

 webs pf the geometric spider. Pig. 331.5 shows 

 one of these spiders in the act of constructing its 

 web. 



All have heard of the gossamer spiders (Aranea 

 obtextrix, and Tetragnatha extensa), which mount 

 high into the air on filmy threads sailing above 

 spires and trees, and anon descending to the ground. 



The appearance of gossamer in the air and on 

 the ground is generally in autumn ; and at this 

 season vast showers have been seen to fall, carpet- 

 ing fields, hedges, and stubble lands. Lister saw 

 a shower in Cambridgeshire in the month of Octo- 

 ber, and Gilbert White saw a similar phenomenon 

 in September. 



The mode in which these .spiders rise is by shoot- 

 ing out their webs, upon which they are borne aloft, 

 and that, too, when not a breath of air is stirring. 

 They appear to depart as if by magic ; nor is the 

 explanation of the fact easy. We have ourselves 

 watched these spiders throw out a line or streamer, 

 exquisitely fine, and mount rapidly, disappearing in 

 an instant. Many observers, and among them Mr. 

 John Murray (Loudon's ' Mag. Nat. Hist.'), consider 

 the phenomena to be electrical. This writer states 

 that the aeronautic spider can propel its threads 

 both horizontally and vertically, and at all relative 

 angles, both in motionless air or in an atmosphere 

 agitated by winds ; nay, it can dart its thread against 

 the current, or, as the sailor would say, in the 

 wind's eye, which he contends depends on some 

 electric action. On the contrary, Mr. Blackwall 

 denies that spiders have the power of darting out 

 their thread in motionless air, and attributes the 

 extension of the lines entirely to atmospheric cur- 

 rents ; but we ourselves have watched the spiders 

 take flight in sultry weather, when there has not 

 been the slightest perceptible movement of the air, 

 and indeed we have thought them at such times 

 the most active. We have caught them, and 

 watched them elevate the abdomen and in an in- 

 stant sweep away from our hand. Mr. Bowman 

 observed aeronautic spiders sailing on a para- 

 chute formed by two diverging fasciculi of threads, 

 and he mforms us that in this ai-rial naviga- 

 tion the adventurer floats with its back downwards, 

 and its legs folded, thus reposing on its streamer. 

 It is probably in quest of minute insects found only 

 at some elevation that these spiders take to flight. 



The Rev. G. White, the Rev. Mr. Kirby, and 

 others, are at a loss to account for the showers of 

 filmy flakes which spread over the ground, and for 

 the reason why the film loses its buoyancy and 

 descends. But the explanation does not appear dif- 

 ficult, much less so, at least, than that of the ascent of 

 the film. Suppose a number of spiders to rise each 

 on a filmy streamer, and having attained a certain 

 elevation, to continue to give out threads in greater 

 abundance, it would soon happen that the streamers 

 of assembled multitudes would become intertangled 

 so as to form flakes, which from a slight electric 

 change in the state of the atmosphere might, though 

 no clouds were visible, become saturated with 

 moisture, and thus rendered of greater specific 

 gravity than the air ; they would then lightly 

 descend, the spiders quitting them. But even with- 

 out being saturated with moisture, such flakes as 

 we have ourselves often seen, and which were 

 formed either purposely by the spiders, or acci- 

 dentally by the intertanglement of many streamers 

 together, would when the upward atmospheric cur- 

 rent, caused by the rarefaction of the heated stratum 

 of air adjacent to the ground, and by which they 

 were carried on high, ceased towards the evening, 

 gradually fall and spread over the dewy grass, 

 becoming completely saturated ; and indeed we 

 deny not that to this rarefaction and upward cur- 

 rent of the air, rather than to any electric causes, the 

 midday ascent of these spiders in sultry breezeless 

 weather, as we have seen, may be attributed. 



All spiders do not weave webs to entangle their 

 prey ; some hunt cal-like for their victims, on which 

 when within due distance they spring side-ways 

 with unernng aim ; the zebra-marked Salticus 

 scenicus adopts this plan. Some chase their prey ; 

 some lie in ambush for it, concealing themselves in 

 rolled up leaves, in holes in walls, in crevices in bark, 

 and some, with deeper craft, in the calyx of a flower. 

 Many of the hunting spiders, as the huge Mygale 

 of South America ; the Thomisus venatoiius of the 

 West Indies ; the Cteniza or Mygale caementaria, 

 and the Lycosa Tarantula, construct singular nests 

 Vol.. il. 



or dwellings in the ground, to which, as the lion to 

 his lair, they return with their victims. 



It was respecting that hunting spider, the My- 

 gale, which weaves no web, that Madame Merian 

 concocted her fabulous account, relative to its cap- 

 ture of humming-birds, and Fig. 3316, from her 

 illustration, depicts the poor bird in the clutches of 

 its foe. We refer for some observations on this 

 point to vol. I. p. 378, lower part of the first column 

 et seq. Some spiders, as the Lycosa piratica, skim 

 over the surface of the water in pursuit of prey, and 

 the Argyroneta aquatica and other congeners dive 

 under water and there seize their food, their bodies 

 being kept unwet by an atmosphere of air surround- 

 ing them. There too beneath the water do they reside 

 in a filmy dwelling, or air-filled diving-bell, attached 

 by threads to plants; this they close up, rendering it 

 like a cocoon, and in it pass the winter season, in a 

 state of hybernation. We have already alluded to the 

 genus Mygale, which as we have said makes singu- 

 lar domiciles in the earth. One species in the West 

 Indies digs a hole of about three inches in depth, 

 and lines it with a tough thick leathery web, of a 

 rufous colour, with a firm lid capable of being opened 

 or shut at pleasure ; another species from the same 

 place composes a similar nest of clay, lining it with a 

 silken tapestry, of a texture like that of very fine 

 glove-leather, with a circular door, the size of a 

 crown piece, formed of several layers of similar 

 compact tissue, having an elastic hinge, and fitting 

 the aperture so accurately that the joining is with 

 difficulty detected. 



An allied species, found in Southern Europe 

 (Mygale caementaria), forms a somewhat similar 

 structure. She selects as the site of her nest a place 

 destitute of grass, and having such a slope as to 

 give quick drainage to the water. Here, in the 

 firm dry soil, she digs a pit to the depth of one or 

 even two feet, and of equal diameter throughout. 

 This she lines with a tissue of close silken threads, 

 and forms a deep conical nest or dwelling, of a thick 

 and warm fabric. The entrance is closed with a 

 circular valve or lid, composed of several layers of 

 earth, intermingled and bound firm with silk, and 

 capable of being opened or shut at pleasure, turning 

 on a silken hinge. So accurately does this lid fit 

 the rim of the nest, that it might seem to have been 

 fashioned by the hand of a human artificer. Fig. 

 3317 shows this species and its nests: A, the nest 

 shut ; B, the nest open ; C, the spider ; D, the eyes 

 magnified ; E, F, parts of the foot and claws mag- 

 nified. 



Fig. 3318 represents the long-legged House-Spi- 

 der (Pholcus phalangio'ides) often seen rapidly run- 

 ning along the walls of our rooms in autumn. It 

 spins a very loose irregular web, and pursues gnats 

 and other flies with great eagerness. 



Spiders envelope their eggs in a cocoon of silk ; 

 these are attached often by long threads to stems, 

 palings, or spikes of grass, as seen at Fig. 3319, 

 where three different examples are given. 



Towards the latter part of summer clusters of the 

 eggs of the Epeira diadema may be observed in 

 great abundance on bushes, hedges, &c. When 

 hatched, the young all keep together, and appear 

 huddled up into a ball, from which very fine lines 

 may be observed to diverge over the adjacent 

 leaves, forming a delicate maze. It is amusing to 

 see the living bubble burst when touched, and the 

 alarmed multitude scatter in every direction; nor 

 is it uninteresting to see them reassemble, and 

 huddle together as before. Fig. 3320 represents 

 the progress of the egg of the garden spider : a, the 

 egg, natural size ; B, the egg magnified, showing 

 the white cicatricula in the centre : C, the egg with 

 the germ enlarged ; a, the head ; b, the body of the 

 enclosed young : d, the young spider (magnified) 

 ready to moult its first skin. 



Some spiders, as the Lycosa saccata, carry their 

 sac or cocoon of eggs with them wherever they 

 travel. The species named, one of the hunting 

 tribe, holds this cocoon between her hind legs, and 

 manifests the greatest anxiety in its preservation. 

 The young when hatched cluster over her body. 

 Another species, the Clotho Durandii, Latreille 

 (Uroctea quinque-maculata, Duf.), found in Egypt 

 and Dalmatia, and also in the mountains of Nar- 

 bonne, the Pyrenees, and the rocks of Catalonia, 

 weaves in the fissures of stones or crags a tent of 

 admirable workmanship in which to rear her young. 



Spiders, the destroyers of insects, themselves fail 

 a prey to insects in their turn. Among their ene- 

 mies is a species of Ichneumon-fly, Sphex, called 

 in Savannah black and yellow masons, besides other 

 species. These insects make oblong cases of clay, 

 which they plaster in layers to roofs, ceilings, or 

 other convenient places. When a case is finished, 

 they lay an egg inside at the end, and then fill it 

 with spiders and plaster it up. The larva by the 

 time it eats them all is mature, and spins a thin 

 shroud, changing into a chrysalis. It would appear 

 that the spiders are paralyzed by these Ichneumon- 

 flies, probably by means of the sting ; at all events 



they are only just capable of moving, but remain 

 plump and fresh. Very rare spiders are often found 

 in these prisons, and some which are never seen 

 elsewhere, and which live, it is to 'oe supposed, on 

 the topmost branches of the highest trees. The 

 number of spiders which thus fall victims is ex- 

 tremely great. But we must not linger on spiders ; 

 the formidable scorpion demands a short notice. 



The sight of a large scorpion advancing wiih his 

 many-jointed tail elevated, and ready to inflict a ve- 

 nomous wound, will give us some idea of the force 

 of that expression, " a lash of scorpions," the fulness 

 of which can only be felt in a country where these 

 dreaded creatures abound. In their appearance, as 

 well as in their disposition, these animals have much 

 to disgust the ordinary observer, and it must be 

 owned that they are formidably armed. The max- 

 illae, which in insects are small, are here developed 

 into enormous crab-like claws, capable of seizing 

 with great power, and of crushing fheir prey. Be- 

 sides these, we find the mandibles forming on each 

 side of the mouth a smaller but similar claw, for the 

 purpose of holding the food which they are in the 

 act of eating. The tail terminates in a sharp curved 

 sting, which, analogous to the poison-fang of a ser- 

 pent, instils venom into the wound it makes. 



The body of the scorpion is composed of a broad 

 cephalo-thorax, covered with a single plate, and suc- 

 ceeded by an abdominal portion of seven rings over- 

 lapping each other. To this succeeds a caudal pro- 

 longation of six joints. Scorpions have six or eight 

 eyes, two on each side of a dorsal furrow, on the 

 middle of the cephalo-thorax, and two or three at 

 each anterior angle of the latter. 



Scorpions tenant the hotter regions of both hemi- 

 spheres, concealing themselves under stones, among 

 crumbling ruins, in obscure corners of houses, and 

 the like. They run very actively, arching the tail 

 over the back, and in attacking their prey seize it 

 with their claws, and instantly pierce it with the 

 sting. They spare not even their own species. 

 Maupertuis put a hundred scorpions together, and a 

 murderous conflict immediately ensued ; almost all 

 were massacred in a few days and devoured by the 

 survivors. 



The sting of the common scorpion of Southern 

 Europe and Barbary (Buthus occitanus, Leach), or 

 the six-eyed European species (Scorpio Europaeus), 

 is not fatal except to small animals and insects. 

 But in the hotter regions there is some degree of 

 danger. In South America the sting of some kinds 

 has been found to occasion fever, numbness of the 

 limbs, and dimness of sight, lasting for two or three 

 days, and death is said to result sometimes from the 

 wound of the black scorpion of CVylon. Mr. Kirby 

 states that the only means of saving the lives of our 

 soldiers who were stung by these creatures in Egypt 

 was amputation. 



The scorpion produces its young alive, and they 

 do not arrive at maturity till after the lapse of two 

 years. During the first days of their existence they 

 are carried by the female on her back. She then 

 keeps close in her retreat, and assiduously guards 

 them. In about a month they are capable of shift- 

 ing for themselves. 



Fig. 3321 represents the African scorpion (Scorpio 

 Afer, Linn. ; Buthus Afer, Leach). The scorpion is 

 among the animals represented on the sculptured 

 remains of ancient Egypt. 



Turning to the Trachearea, we may first notice 

 those minute creatures, the mites (Acaridae), many 

 of which are parasitic, and known as ticks (Ixodes) ; 

 they infest animals of various kinds, and even in- 

 sects ; we often see the common dor-beetle covered 

 with these pests. Some species live in cheese, some 

 on leaves, or beneath the bark of trees, and some, 

 as the Hydrachna, are aquatic. 



In the trenus Acarus the palpi are short, or con- 

 cealed and forked ; the body is soft, and the feet 

 have at their extremity a vesicular cushion. Fig. 

 3322 represents the domestic mite (Acarus domes- 

 ticus) very common in collections of insects and 

 cabinets of stuffed birds, to which it proves ex- 

 tremely destructive, nor will camphor altogether 

 prevent its incursions. 



Fig. 3323 represents, highly magnified, the Acarus 

 Scabiei, found in the pustules of a well-known cuta- 

 neous disease, "la gale humaine " of the French, 

 and for which sulphur is a remedy. Bruelli and 

 Dr. Galet have detected this animal in the skin, and 

 have observed it multiply ; and their inference is 

 that if it does not produce it accompanies the dis- 

 order. Indeed Dr. Galet ascertained that these 

 mites transferred to the skin of a healthy person 

 communicate the disease. 



Fig. 3324 represents the Sparrow mite (Acarus 

 passerinus), or Bat-tick of Geoffrey. It is parasitic, 

 and remarkable for the size of the third pair of 

 limbs. 



Fig. 332.5 the Harvest-Bug, greatly magnifi-ed. 

 This species, "Le Rouget" of the French (Leptus 

 autumnalis), abounds during summer and autumn 

 on the grass of the meadows, and the brushwood of 



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