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SPIDERS , the See also:common See also:English name of Arachnids (q.v.) of the See also:order Araneae, resembling the See also:Pedipalpi in many structural points, but differing from them as well as from all other Arachnids in retaining See also:short abdominal appendages known from their See also:silk-manipulating See also:function as spinnerets or See also:spinning mamillae, with which are associated silk gland*. It is probably owing to the See also:possession of such glands and the varied purposes for which the, silk is used that spiders as a See also:group far surpass the other orders of Arachnids, with, the possible exception of the Acari (mites and See also:ticks), in diversity of See also:form and of See also:size, in See also:numbers of genera and See also:species., in extent of See also:geographical See also:distribution, and in See also:adaptation to varied habitats. Except in the extreme See also:north and See also:south, and on the tops of the highest mountains, where there is no See also:insect See also:life as See also:food See also:supply, spiders are found all over the See also:world, even in isolated oceanic islands. They occur up See also:mountain slopes as far as vegetation extends, in tropical valleys and forests, in open grassy plains, in sandy deserts, and even in fresh-See also:water ponds and between See also:tide-marks on the seashore. Some are nocturnal, some diurnal; some catch their See also:prey by See also:speed of See also:foot, some by cunningly lying hid, some by means of silken nets. The phenomena known as " protective resemblance," or similarity to inanimate See also:objects or vegetation, and the kindred phenomenon of " See also:mimicry," or beneficial likeness to certain protected species of animals, are common in the group. In these particulars, considered in their entirety, spiders show a marked contrast to other Arachnids, such as the scorpions, pedipalps, See also:book-scorpions and so-called See also:harvest spiders, which by comparison are remark-ably See also:uniform, within the limits of the orders, in, structure, habits and other respects. Spiders, in short, must be regarded as the most highly organized and the most successful members of the class Arachnids. Their success in the struggle for existence, as already indicated, must be assigned in a See also:great measure to the possession of silk glands and to their See also:power of manipulating the silk for a variety of purposes. Several facts point to the conclusion that, the See also:primary use of this secretion was the formation of See also:egg-cases or cocoons by the See also:female, for this is the only See also:constant use for which the silk is employed, without exception, by all species. The second step in the See also:evolution of spinning instincts was probably the making of a silken chamber for the reception of the cocoon itself and for the See also:protection of the See also:mother while guarding it and her newly-hatched See also:young. If an See also:aperture for See also:ingress and See also:egress, for purposes of feeding, were See also:left in the See also:wall of such a chamber, there would arise in a rudimentary form what is known as the tubular See also:nest or See also:web; and the next important step was possibly the See also:adoption of such a nest as a permanent See also:abode for the spider. Some spiders, like the Drassidae and Salticidae, have not advanced beyond this. See also:stage in architectural See also:industry; but next to the cocoon this See also:simple tubular See also:retreat—whether spun in a crevice or burrow or simply attached to the See also:lower See also:side of a See also: When on the See also:watch for prey the spider slightly raises the lid and, peeping through the chink, darts like a flash upon any See also:beetle or See also:fly that unwittingly passes within reach. Quite commonly the burrow has a second passage See also:running obliquely upwards from the main passage to the See also:surface of the soil, and this subsidiary track may itself be shut off from the main See also:branch by an inner door, so that when an enemy has forced an entrance through the main door, the spider retreats behind the second, leaving the intruder to explore the seemingly empty burrow. There is no doubt that the primary See also:influence that has guided the evolution of the See also:architecture of the burrowing spiders has been that great See also:necessity for the preservation of life, avoidance of enemies and protection from adverse See also:physical conditions like See also:rain, See also:cold or drought. And when we turn to the other line along which the web-See also:building instinct has been developed we find that the primary guiding influence has been that second great vital necessity, namely the necessity of getting food. Reference has already been made to the silken tube or See also:tent, of simple structure, with an orifice at one or both ends, as the possible origin of all snares, however complex they may be. Perhaps the most rudimentary form of snare arose from the spinning of threads See also:round the mouth of the tube to hold it in See also:place. Be that as it may, the snare in many instances, as in that of the Agalenidae (Tegenaria, Agalena), a See also:family closely allied to the Lycosidae, is a See also:horizontal sheet of webbing, upon which the spider runs, continuous with the lower See also:half of the aperture of the tube, of which it is simply an See also:extension. A very similar sheet is spun by a species'of Linyphia, one of the Argyopidae, but in this See also:case there is no tube connected with the web and the spider hangs suspended beneath the horizontal netting. Snares of another type consisting of a tangled See also:mass of threads amongst which the spiders pick their way with ease, but which are impassable to See also:insects, are spun by members of the Theridiidae and Pholcidae; but by common consent the so-called orbicular web, so characteristic of the Argyopidae but by no means confined to them, is regarded as manifesting the greatest 'perfection of instinct in snare-spinning. These webs, which are typically subcircular in form, consist of a See also:system of threads radiating from a common centre and crossed at intervals, and approximately at right angles, by a See also:series of concentric lines, the whole being suspended in a triangular, quadrangular or polygonal framework formed of so-called See also:foundation lines, attached to the branches or leaves of trees or other See also:firm objects in the neighbourhood. Passing back from the centre of the web to the underside of an adjoining See also:leaf or some other sheltered spot runs a single See also:thread, the trap line affording passage to the spider to and from the sheltered spot and the snare itself. At whatever spot an insect becomes entangled in the See also:frame, the vibration set up by its struggles is transmitted along the nearest radiating thread to the centre and thence up the trap line to the shelter where the occupant lurks awaiting the See also:signal. No sooner is the vibration perceived than the spider descends with all speed to the centre, and by feeling the ends of the radiating lines learns which is ashakeand rapidly, without the possibility of See also:mistake, makes its way to the entangled insect. The probable See also:reason for the wall-lines being concentric is that lines passing over the radii as nearly as possible at right angles are the shortest that can be laid on; they therefore use up a smaller quantity of silk and take a shorter See also:time to spin than threads See also:crossing the radii in any other direction; and at the same time they afford them the greatest possible support compatible with delicacy and strength of construction. On See also:account of its delicacy no web is more difficult to see than one of the orbicular type above described. Its whereabouts is thus, to a great extent, concealed both from enemies searching for spiders and from insects suitable for food; and its open meshwork of strong threads makes it much less liable to be beaten down by rain or torn to shreds by winds than if it were a See also:flat sheet of closely See also:woven silk. In constructing, therefore, a snare of radiating and concentric lines, it seems that a spider economizes both time and silk and in addition renders the web as strong and as serviceable and yet as delicate and invisible as possible. Perfect orbicular webs are made by many genera of Argyopidae (Zilla, See also:Meta, Gasteracantha), the best-known example being that of the common See also:garden spider of See also:England, Aranea or Epeira diademata; but these webs are not associated with any tubular retreat except such as are made under an adjoining leaf or in some nook hard by. Some tropical members of the family belonging to the genus Nephela, however, spin a web which is intermediate in structure between that of Aranea and the See also:complete sheet-like web of Agalena. It covers an See also:area of about one-third of a circle and its radiating threads diverge from the mouth of a See also:funnel-shaped tube resembling in every respect the tube of the last-mentioned genus. Again some species of Dictyna, belonging to the Amaurobiiftae, also have a tubular retreat opening on to the surface of a snare in which a crude attempt at a radial and concentric arrangement of the threads is perceptible. The See also:interest of these two types of web lies in the fact that they See also:bridge over the structural See also:gap between the simple sheet-web of Agalena and the perfected See also:orb-web of Aranea. Dictyna may be cited as an example of a group of spiders, sometimes called the Cribellata, which have certain spinning glands and appliances not possessed by others. These glands are represented externally by a See also:special See also:plate, the cribellum, which lies in front of the See also:ordinary spinning mamillae, and by a See also:comb of short bristles, the calamistrum, placed in the penultimate 'segment of the left of the last pair. By means of the calamistrum the silk secreted by the cribellum is teased into a See also:fine thread which is See also:twisted round the main threads of the web, giving it a very characteristic woolly or flocculent See also:appearance. There are many other uses to which silk is put, besides those mentioned above. By trailing a thread behind them spiders are able to drop from any height to the ground and to retrace their steps with certainty to a particular spot. The possession of silk-glands has also profoundly influenced the geographical distribution of spiders and has enabled them to See also:cross arms of the See also:sea and establish themselves on isolated oceanic islands which most of the orders of See also:Arachnida are unable to reach. This is effected by the so-called habit of " ballooning " practised by very young spiders, which See also:float through the See also:air, often at great altitudes, in the direction of the prevalent winds. It was formerly supposed that this See also:custom was See also:peculiar to a single species, which was called the " See also:gossamer " spider from the fact that the floating webs, when brought to the See also:earth by rain or intercepted by bushes and trees, coat the foliage or grass with a sheeting of gossamer-like silk; but the habit is now known to be practised by the newly-hatched young of a great variety of species belonging to several distinct families. As a commercial product spider-silk has been found to be equal, if not See also:superior, to the best silk spun by lepidopterous larvae; but the cannibalistic propensities of spiders, making it impossible to keep more than one in a single receptacle, coupled with the difficulty of getting them to spin freely in a confined space, have hitherto prevented the silk being used on any extensive See also:scale for textile fabrics. The methods of catching prey adopted by spiders are extremely varied. The nets or snares are highly efficient for this purpose. Amongst the threads, which entangle the wings and legs of intercepted prey, the spiders are perfectly at See also:home and can See also:pounce on the struggling victim at once if it be small and harmless or keep at a respectful distance, checking all efforts at See also:escape, if it be poisonous or strong. If in the latter case the spider be afraid to come to close quarters, various devices for securing it are resorted to. The Theridiidae eject on to the insect from their spinning mamillae drops of liquid adhesive silk; the Argyopidae, steadying it with the tips of their See also:long front legs, sweep additional strands of silk over it with the legs of the hinder pair; the Agalenidae, attaching a long thread to a point hard by, run round and round the victim in circles, gradually winding it up beyond all See also:hope of breaking loose. Two genera of Argyopidae (Hyptiotes and Theridiosoma) construct spring-nets out of their incomplete webs of the orbicular type. To the web is attached a trap-line which when See also:drawn taut holds the snare stretched and tight, and when relaxed loosens the whole structure so that the threads fall together. When an insect strikes the web the spider loosens his hold of the trap-line, thus enveloping the victim in a tangle of threads which would otherwise not come into contact with it. Spiders which spin no snare are dependent for capturing prey for the most See also:part upon their quickness or See also:powers of lying concealed. Many Thomisidae lurk amongst the stamens and petals of See also:flowers, which they closely match in See also:colour, waiting to seize the insects which visit the blossoms for See also:nectar. Examples of Selenops (Clubionidae) See also:lie flat and absolutely still on the bark of trees, to which their coloration assimilates, and spring like a flash of See also:light upon any insect that touches their legs; the Lycosidae dart swiftly upon their prey; and the Salticidae, which compared with other spiders have keen powers of See also:vision, stealthily stalk it to within leaping distance, then, gathering their legs together, See also:cover the intervening space with a spring and with unerring aim seize it and See also:bury their fangs in its See also:body. One genus of Thomisidae (Phognarachne), which inhabits the See also:Oriental region, adopts the See also:clever See also:device of spinning on the surface of a leaf a sheet of web resembling the fluid portions of a splash of See also:bird's dung, the more solid central portions being represented by the spider itself, which See also:waits in the See also:middle of the patch to seize the butterflies or other insects that habitually feed on birds' excrement and are attracted to the patch mistaking it for their natural food. The sexes of spiders are distinct. Except in the case of the water-spider (Argyroneta) the See also:males are smaller, sometimes very much smaller, than the See also:females, but have proportionately longer legs and smaller bodies. When adult the males may always be distinguished from the females by the presence of a pair of horny intromittent See also:organs, one of which is lodged in the terminal segment of each palpus or appendage of the second pair. In its simplest form this is a hollow See also:flask-shaped horny piece, consisting of a dilated basal portion and a terminal spiniform portion with an orifice at the See also:apex; but its structure is frequently complicated by See also:accessory processes and outgrowths which aid copulation and serve to protect the delicate point from injury. In the breeding See also:season the male deposits drops of sperm on a sheet of webbing, picks it up in these flasks by means of capillary attraction and carries it about until he falls in with a female. During pairing he thrusts the tip of these organs into the seminal vesicles of the female and the eggs are fertilized as they pass out of the oviduct. Cases of parthenogenetic See also:reproduction, or reproduction without the intervention of the male, have been recorded in the case of two genera (Filistata and Tegenaria), and may be commoner than is usually supposed. All spiders are oviparous. The number of eggs produced at a time varies enormously according to the species, from about half a dozen, more or less, in some See also:ant-mimicking Attidae or See also:jumping spiders to many hundreds in the larger orbicular-webbed spiders of the family Argyopidae. The first See also:act of the female after oviposition is to wrap her eggs in a casing of silk commonly called the cocoon. The cocoon varies greatly in size, shape and consistency according to the nature of the spider that makes it. Sometimes, as in Pholcus, it ismerely a thin network of silk just sufficient to hold the eggs together. More often it consists of a thick felting of silk, either spun in one continuous piece into a globular form, as in the Aviculariidae, or composed of two plate-like pieces, an upper and a lower, See also:united at the edges and lenticular in shape, as in some of the Lycosidae. Sometimes it is woolly and flocculent, sometimes smooth like See also:parchment, and its shape depends in a large measure upon the habits of the female towards her offspring. As a See also:rule terrestrial spiders guard the cocoon in the permanent burrow, as in the trap-door spiders, or in the silken retreat which acts as a temporary nursery, as in the Salticidae. Other species of wandering habits carry the cocoon about with them, sometimes attached to the spinnerets, as in the Lycosidae, sometimes tucked under the See also:thorax, as in the large tropical See also:house-spider, Heteropoda regia, one of the Clubionidae. The females of some snare-spinning species, like the Pholcidae, carry it in their jaws; but in the case of the Argyopidae the females usually leave the cocoon to its See also:fate as soon as it is constructed, sometimes See also:rolling it in a leaf, sometimes attaching it by a stalk to a branch. It is in this and related families that the greatest diversity in the colour and form of the cocoon is found. In these spiders, too, the newly-hatched young shift for themselves as soon as they emerge from the cocoon; in others that guard the cocoon the young stay for a longer or shorter time under their mother's protection, those of the wandering Lycosidae climbing on her back to be carried about with her wherever she goes. There is no See also:metamorphosis during growth such as occurs in some insects, the young being hatched with its full See also:complement of appendages and only differing from its parents in characters of comparatively See also:minor importance. Growth is accompanied by a See also:succession of moults, the spider emerging from its old skins by means of a fracture which extends along the front and sides of the cephalothorax just beneath the edge of the See also:carapace. It is only at the final See also:moult that the sexual organs are mature, the two sexes being alike in the earlier stages of growth. Until maturity is reached the spider has the power to repair lost or damaged limbs. If a See also:limb be lost at an See also:early stage it maybe re-grown in perfection; but at later stages it is only imperfectly reproduced and is shorter and thinner than the other limbs. Rapidity of growth and See also:longevity vary greatly according to circumstances and: to the species. In See also:northern and temperate latitudes where insects disappear in the winter, species of Argyopidae like Aranea diademata, live only for a single season. The young emerge from the cocoon in the early spring, grow through the summer, and reach maturity in the early autumn. The sexes then pair and perish soon after the female has constructed her cocoon. Species of other families (Lycosidae, Clubionidae) may live for a few seasons, hibernating in the soil or amongst dead leaves; and examples of the larger spiders (Aviculariidae) have been kept aline in captivity for several years. Owing to the smaller size of the male and the greater voracity of the female, the male makes his advances to his See also:mate at the See also:risk of his life and is not infrequently killed and eaten by her either before or after pairing has been effected. Fully aware of the danger, he pays his addresses with extreme caution, frequently waiting for See also:hours in her vicinity before venturing to come to close quarters. Males of .the Argyopidae hang on the outskirts of the webs of the females and signal their presence to her by jerking the radial threads in a peculiar manner. Other web-spinning spiders (Tegenaria) have somewhat similar habits; and the male of the See also:park-web spider (Atypus), one of the Mygalomorphae, taps the walls of the tubular web of the female before daring to bite a hole in it and descend into her burrow. Most curious of all is the courtship of the males of some species of Salticidae, or jumping spiders, which are decorated with plumes or coloured stripes or iridescent patches. These they display before her, posing and performing extraordinary antics in her presence exactly as See also:cock birds behave towards their hens. Lastly. the males of some species of spiders differ from the females in possessing stridulating organs 'consisting of horny ridges and spikes and lodged either between the mandible and palpus as in some species allied to Linyphia, one of the Argyopidae, or between the cephala-thorax and See also:abdomen as in Steatoda, one of the upon stillness, and the instinct to keep stationary without moving Theridiidae and Cambridgea, one of the Agalenidae. It is believed that the males of these species signal to their females by means of the See also:sound these organs emit. The greatest disparity in size between the sexes is met with in the tropical genus Nephila, the females of which are gigantic representatives of the Argyopidae. The male, however, is a veritable pigmy beside the female, and during copulation presents the appearance of a See also:parasite attached to her abdomen. It has been suggested that the diminutive size of the male' is of great See also:advantage to him during courtship, because he is enabled to move easily thereby to escape from her clutches should she turn upon him with hostile See also:intent. All spiders possess a pair of See also:poison-glands, one in each of the chelicerae or mandibles and opening by means of a duct at the tip of the See also:fang. The primary function of this poison is to kill the prey upon which they feed, its See also:action being very rapid upon insects. In a great See also:majority of cases, however, it is comparatively innocuous to human beings, despite legends to the contrary that have arisen in connexion with certain species like the tarantula. The bite, however, of any spider, strong enough to See also:pierce the skin, may give rise to a certain amount of See also:local inflammation and See also:pain depending principally upon the amount of poison injected. The bite, for example, of large species of the family Aviculariidae, sometimes called Mygales, and sometimes, but erroneously, known as tarantulas, species which have fangs half an See also:inch long and as See also:sharp as needles and a considerable quantity of poison, may be very painful, though seldom serious provided the See also:health of the patient be See also:good. There is one possible exception, however, to the innocuous nature of the poison and this is supplied by the species of the genus Lathrodectus, one of the Theridiidae. There is no actual See also:proof that this spider is more poisonous than others, but it is a significant fact that its species, inhabiting countries as widely separated as See also:Chile, See also:Madagascar, See also:Australia, New See also:Zealand and South See also:Europe are held in great fear by the indigenous See also:population, and many stories are current of serious or fatal results following their bites. Many of the species of these spiders, moreover, are very conspicuously coloured, being either wholly See also:black or black relieved by fiery red spots, forcibly suggesting that they are warningly coloured. Some of the species of Aviculariidae also appear to be warningly coloured with black or black and red, and their coloration is associated with the urticating nature of their bristles, which makes them highly unpalatable to vertebrate foes. So far as is known, however, only the large spiders belonging to this group possess this special means of See also:defence, and in many other species this is accompanied by highly-developed stridulating organs resembling those of rattlesnakes and scorpions in function. Others again, like Casteracantha and Acrosoma, belonging to the Argyopidae, are armed with sharp and strong abdominal spines, and these spiders are hard-shelled like beetles and are spotted with black on a reddish or yellow ground, their spines shining with See also:steel-See also:blue lustre. The majority of spiders, however, are soft-skinned and succulent, and are tasty morsels for insectivorous See also:reptiles, birds and mammals. Hence as a very See also:general rule the coloration makes for concealment under natural conditions of existence, and the instincts which See also:lead to concealment are very highly developed. As instances of procryptic or celative coloration may be mentioned that of the species of the genus Dolomedes, one of the Lycosidae, which lives amongst reeds and is marked with a pair of See also:longitudinal yellow lines which harmonize with the upright stalks of the vegetation, and Lycosa See also:pitta, which lives on the sand, can scarcely be seen on account of its mottled See also:pattern: Sparassus smargdulus and the species of Pecucetia, which are found amongst grass or See also:low See also:green herbage, are mostly green in colour, and Salticus scenicus is banded with See also: One interesting phenomenon in spider-life seems to be directly and certainly traceable to this influence, and that is mimicry of ants. In several families of spiders, but principally in those like the Clubionidae and Salticidae, which are terrestrial in habits, there are species which not only live amongst ants, but so closely resemble them in their shape, size, colour and actions that it requires a practised See also:eye to distinguish the Arachnid from the insect. Now the See also:Pont pilidae or See also:mason wasps See also:provision their cells with insects of many different kinds, as well as with spiders; but, of the hundreds of species of these wasps that have been described from different parts of the world., only one is known to use ants for this purpose; and this species is not one that preys upon spiders. On the other See also:hand it has been specially recorded of two of the species of spider-destroyers that they have great dislike and apparent fear of these little poisonous Hyrnenoptera. So, too, does it appear that ants are entirely immune to the attacks of Ichneumonidae, which destroy hosts of other insects and of spiders by laying their eggs upon their bodies. But since ants are not persecuted by these two families of See also:Hymenoptera, the greatest enemies spiders have to contend with, it is evident that mimicry of ants is of supreme advantage to spiders. Ants, however, are not the only animals mimicked by spiders. Some members of the Argyopidae (Cyclosa) are exactly like small snails; others (Cyrtarachne) resemble Coccinellidae in shape and colour. Now, Coccinellidae (ladybirds) are known to be highly distasteful to most insectivorous mammals and birds, and snails would be quite unfit food for the Pompilid or Ichneumonid larvae, so that the reason for the mimicry in these cases is also perfectly clear. The exact extent, however, to which each particular class of enemy has affected the protective habits and attributes of spiders is by no means always evident; and it is impossible to discuss the question in detail within the limits of a short See also:article. But two instances of extreme deviation from the ordinary mode of life due, apparently, like ant-mimicry, solely, if not wholly, to the persecution of Hymenoptera, may be cited as illustrations of the profound effect upon habit brought about by long-continued persecution from enemies of this See also:kind. This deviation is the adoption of an aquatic mode of life by the See also:European fresh-water spider (Argyroneta) and by the marine spider Desis, which is found on the shores of the See also:Indian and Pacific Oceans from Cape See also:Colony to eastern Australia. Desis lives invariably between tide-marks upon the rocks and See also:coral reefs, and may be found at low tide either crawling about upon them or See also:swimming in tidal pools and feeding upon small See also:fish or crustaceans. As the tide rises the spiders take See also:refuge in crevices and spin over their retreat a sheet of silk, impervious to water, beneath which they lie in safety with a supply of air until the ebb exposes the site again to the See also:sun. The fresh-water spider (Argyroneta) lives amongst the weeds of lakes and ponds and, like Desis, is quite at home beneath the water either swimming from spot to spot or crawling amongst the stems of aquatic See also:plants. As a permanent home the spider makes beneath the surface a See also:thimble-shaped web, with inverted mouth, anchoring it to the weeds. He then ascends to the surface, carries down a bubble of air and releases it inside the mouth of the silk-thimble, thus replacing a certain amount of water. This action is repeated until the See also:domicile is filled with air, when the spider takes possession of it. The spider owes its name Argyroneta or the See also:silver swimmer to its silvery appearance as it swims about under water enveloped in air, and its power to retain an envelope of air on its sternum and abdomen depends upon the circumstance that these areas are beset with hairs which prevent the water reaching the integument; but the air retained by these hairs can be released when the spider wishes to fill its subaqueous home with that See also:element. Argyroneta feeds principally upon flies or gnats, which it seizes from below as they light upon the surface of the water. In the breeding season the male spins a See also:bell or thimble near that of the female and joins the two by means of a silken passage. The female attaches her eggs to the inner wall of her own home, and the young when large enough to shift for themselves have the bell-making instinct fully developed. Since the adoption of an aquatic mode of life by Desis and Argyroneta involves no increased facilities in getting food, and merely substitutes for ordinary terrestrial enemies fishes and crustaceans in the former case, and fishes, amphibians, and insectivorous water-insects in the latter, the supposition is justified that the See also:change in environment is due to the unremitting persecution of Pempilidae and Ichneumonidae, which would not venture to pursue their prey beneath the water's surface. The habits of certain other spiders suggest the origin of the perfect adaptation to aquatic conditions exhibited by Desis and Argyroneta. The nature of the integument and its hairy clothing in all spiders enables them to be plunged under water and withdrawn perfectly dry, and many species, even as large as the common English house-spider (Tegenaria), are so lightly built that they can run with speed over the surface of See also:standing water, and this See also:faculty has been perfected in genera like Pirata, Dolonzedes and Triclaria, which are always found in the vicinity of lakes or on the edges of See also:rivers and streams, readily taking to the water or running down the stems of water plants beneath its surface when pursued. Some species of Dolomedes, indeed, habitually construct a raft by spinning dead leaves together and float over the water upon it watching for an opportunity to dash upon any insect that alights upon its surface. Geologically, spiders date from the Carboniferous See also:Period, Arthrolycosa and others from the See also:coal beds of Europe and North See also:America being closely allied to the existing genus Liphistius. Remains of spiders from the Baltic See also:amber beds of Oligocene See also:age and from nearly coeval fluviatile or lacustrine deposits of North America belong to forms identical with or closely related to existing genera, thus proving the great antiquity of our See also:present spider See also:fauna. (R. I. Additional information and CommentsThere are no comments yet for this article.
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