Popular Science Monthly/Volume 62/December 1902/Some Arachnids at Hanover, Cape Colony
| SOME ARACHNIDS AT HANOVER, CAPE COLONY. |
By S. C. CRONWRIGHT SCHREINER,
HANOVER, CAPE COLONY.
WHEN I left Cape Town for Hanover, my friend, Dr. Purcell, of the South African Museum, the leading South African authority on spiders and their kin, asked me to send him any of these creatures I might capture. The district of Hanover, he said, and indeed, practically, the whole high Karoo plateau, was unexplored arachnologically; there had been no collection from the high plateau, and he was particularly anxious to have one to compare with the arachnid fauna of the lower-lying Great Karoo.
I have devoted special attention to spiders, Solifugæ and scorpions, though, naturally, other things have found their way into the collecting bottles. These have all, from time to time, been sent to Dr. Purcell for classification, and the results have been, on the whole, as surprising as interesting.
If the reader will take a map of the Cape Colony and follow the railway from Cape Town to Bloemfontein, he will find the little station of Hanover Road lying about midway between De Aar and Naauw Poort Junctions. Nine miles across the veld, southwest from Hanover Road, is the little dorp or village of Hanover, which lies at the foot of two ijzer (iron-stone) kopjes, on a great Karoo flat, 4,700 feet above the sea level. A superb fountain gushes out from a covered furrow at the foot of the kopjes, furnishing an abundant supply of water for the houses and the fruit gardens; a great vley runs east and west past the dorp; groups of kopjes dot the mighty veld at intervals, and purple hills and mountains fringe the clean-cut and distant horizon. Hanover is bare and at times very cold in the winter; but, in the summer, when the willow trees along the water furrows that line the streets, and the fruit trees in the gardens about the white houses, are green, the little dorp is, of all small towns I have seen, by far the most beautiful. It lies like a great flower on the brown Karoo—not as an excrescence, but as though it were part of the veld. There are old men here who have seen lions in the neighborhood, and younger men who have seen wildebeeste (gnus) career through the streets.
My collecting has been confined practically to the commonage in the immediate neighborhood of the dorp, over which, under martial law, I have had a permit to walk. But fortunately the Dutch farmers have been interested in my work, and both adults and children have gladly taken bottles of spirits and collected on the farms. I have thus received many interesting specimens of spiders and Solifugæ. The farmers are pleased that so many new things have come out of their district, and are eager that it shall hold a front place in the great museum at the capital. A gray-headed old man handed me a bottle of spiders the other day with the remark 'Ik denk Hanover is nou zeker vóór' ('I expect Hanover is in front now'), and was much pleased when I told him how well Hanover was holding its own at Cape Town. The school children too, especially the girls, have done well. I have a couple of charming young friends who, in three weeks, sent me over three hundred specimens, some new and of great interest.
The result of the collecting up to the time of writing is, that, out of over two thousand arachnids I have sent to the museum (and excluding some spiders still undetermined), Dr. Purcell has found some twenty-one families of spiders, comprising more than a hundred species (the great majority of which are new to science), some ten species of Solifugæ (several of which are also new to science), four species of scorpions and one pseudo-scorpion.
One can not speak with any certainty yet, but it would almost seem that the high plateau has, largely, its own peculiar arachnid fauna, which, if it be so, is a very interesting fact.
But the interest does not lie wholly in the finding of an apparently new fauna and many new species of very rare genera; it is perhaps greatest in connection with what has been learned concerning spiders whose habits were thought to be known.
Before passing on to the arachnids, one or two interesting finds in other orders may be noted.
Among snakes, a small rare species (Prosymna sundevalli)—speckled, handsome and non-poisonous—is remarkable as having a hard snout for burrowing into the ground. Another snake is interesting from the manner of its capture. I was reading one evening inside the house and my wife was walking up and down the stoep after the heat of the day, when I heard her call anxiously. I went out and found the snake, which I killed two feet from our open door, for which it was making. A beautiful family are the Kous slangen (garter-snakes). They are very poisonous, but fortunately they are smallish and have very small teeth. The best specimen of these snakes I have caught is perhaps the most beautiful of them all. It is circled throughout its whole length with alternate bright red and deep black bands about half an inch wide. I nearly trod on it, and was warned by the most violent short hisses. I looked down at my feet, and there, standing up on a red iron-stone, was this enraged and lovely creature, swaying to and fro with flattened head, ready to fight. It looked like the gay stalk of some beautiful aloe; and its beauty and pluck so appealed to me that I captured it only with great reluctance. Of course, the kopjes and the flats abound with various lizards, some of the most gaudy colors. For instance, there is one with spiked coat and rough, ringed tail, which has a red head, blue throat, neck and sides, while the back varies from red to brown towards the tail. It sits on a rock and quaintly raises itself up and down on its forelegs. If danger approaches, it slips into a crevice, from whence it can hardly be taken alive, for the spikes catch on the stone so firmly that the lizard is able to resist almost all attempts to take it out. But most interesting, perhaps, are the Geckos (Pachydactylus mariquensis), which the Dutch call getjes, also generally found under stones. They are about six inches long and not so quick in their movements as lizards usually are. This and their defencelessness have induced a peculiar method of protection. Their fleshy tails are quite loosely affixed, being deeply constricted all round where they join the body. A slight touch will break them off—so much so that at times the getje seems almost to throw them off. Then is seen a strange thing. The tail jumps about in the most lively manner, and thus attracts the attention of the pursuer, while the getje quietly and unobtrusively moves away unobserved—and goes and grows another tail! This is a peculiar and yet very effective method of protection; there are other local lizards that part with their tails with comparative ease, but they are quicker in their movements and their tails are not nearly so lively; the method has reached perfection in the case of the getje only. I am generally accompanied in my walks by my wife's little fox terrier. She seldom catches a getje. When she jumps at one, off flies the tail, which she invariably seizes as it plunges frantically about, and the getje escapes. The getjes are of various colors, some very handsome. Some kinds burrow holes in the sand, and these occasionally take possession of deserted nests of the large trap-door spiders. (I say deserted; they may, however, kill the spiders; but I do not think they do.) They somewhat narrow the opening of the tube just under the lid, to about the size of their body, but they leave the lid intact and keep it in use, opening and shutting it (or allowing it to shut itself) at will. On lifting a lid on one occasion, I found the getje in the hole, peering out from under the slightly-gaping lid, with its head just level with the surface of the ground—a very odd sight. I dug down, and at the bottom of the hole found its egg, which it was evidently guarding. On another occasion I found two at the bottom of a large closed trap-door nest. The lid of a nest, when occupied by the getje, does not close so perfectly as when occupied by the spider, due perhaps to the narrowing of the opening. Though generally held to be poisonous, these charming little lizards are really quite harmless. Hottentots have a great dread of the getje, believing that if it bites them, they will live just long enough to reach home, at most till sundown.
Among this miscellaneous collection is a wasp (Mutilla), of which I have found some twelve or fourteen kinds. The males are winged, as usual with wasps, but the females are wingless. She has a red thorax and a yellow-spotted hairy abdomen. She runs very quickly among the karoo bushes, and, if alarmed, hides under them or buries herself in the loose hot sand at their roots. She has to be handled carefully, as she has a very powerful sting. She also stridulates, no doubt a call to her flying mate who, by the way, cannot sting. I have found only three males (one dead in a Stegodyphus nest), but the males are very rare. I do not know why the females are wingless and the sexes so different in appearance. But the same thing occurs with some grasshoppers; I have one kind particularly in my mind, the female of which is dark, huge and heavy, with only rudimentary wings, while the male is small, slight, smart, brick red and a splendid flyer. The variety of grasshoppers and ants here is extraordinary, and the protective shapes and colors are most wonderful. Such protective devices are, of course, quite a feature of the fauna of the bare and stony karoo; but no one who had not seen them could believe how efficacious they are. Even a trained eye may lose an insect while looking at it.
Passing on to scorpions, the four species found here embrace three genera. One kind (Opisthophthalmus austerus), a burrower, is very common; one may catch fifty almost any day. They grow to six or seven inches in length and are pugnacious and poisonous. Most Opisthophthalmi dig holes from one to two feet deep, sometimes but not generally under stones, with the opening oval-shaped like a human eye; but O. austerus here is, as far as my experience goes, invariably found under stones by day, sometimes with only a shallow burrow under the stone, at other times with a burrow ending in a hole which varies in depth, often not being deep enough to hide the scorpion. When you raise the stone you expose the scorpion, which runs to and fro in its now roofless burrow, and, if it has sunk a hole, eventually dives down into that, sometimes tail first. If you irritate these scorpions, they tilt the hind part of the body forward and up by straightening their hind legs under it; then jerking it quickly and stridulating angrily, they rush at you; and most ugly creatures they are—all nippers and sting. The stridulating sound is produced by rubbing the jaws which are lined with short, stiff, yellow hairs against the front edge of the head-plate. The male closely resembles the female up to the last molt, but after that he is longer and slenderer and has longer and slenderer hands (nippers), but he is quicker and more vicious. O. austerus is handsomely marked; the back is dark brown, the sides purple sometimes greenish, and the hands often a rich mixture of red and brown. Scorpions have an organ, like two small delicate white wings, attached underneath the body between and in a line with the last pair of legs, which in the male is toothed along the back edge to the base, while in the female the last quarter is not toothed; its functions are unknown, but it is some delicate sense organ presumably.
The other kinds of scorpions found here do not call for special remark, though it may be noted that one of them (Parabuthus neglectus, Pure.) was not thought to occur so far east. There is, however, a very interesting pseudo-scorpion, a small tailless creature, otherwise much like a scorpion, found under stones and in sand, which has the curious habit of burying itself in the sand, and then, when it wishes to change its quarters and opportunity offers, it seizes a bee or fly by the leg and is thus strangely transported through the air by the flying insect.
Scorpions are of course viviparous and carry their young when small on their back.
The next group, the Solifugæ, is a very interesting one. The Dutch call them Jacht Spinnekoppen or Haar Scheerders, and, as usual, these are the names by which the Solifugæ are generally known in South Africa. Except that the Solifugæ are not spiders (though, outside of scientific circles, held to be so in South Africa), Jacht Spinnekop (hunting spider) is a very appropriate name, for, to the casual observer, they resemble spiders, and they are mighty hunters. Haar Scheerder (hair shearer) is even more appropriate. They are called Haar Scheerders because of their two enormous 'shears.' Many a person believes that, if they get into your hair, you will not get them out again until they have shorn it all off; others believe that they wait until you are asleep and then come and cut your hair off to build their nests with—imaginery operations, suggested no doubt by the name and the shape of the jaws.
I know of no creature which, for its size, is so terribly armed as the Jacht Spinnekop; practically the whole of its huge head is transformed into two pairs of terrible nippers of quite extraordinary size and power. These nippers run straight forward, the eyes being placed just where they emerge above. Each pair of nippers has its own independent nipping action, and, in addition, each has an independent up-and-down and backward-and-forward motion, giving the jaws an awful tearing power, so that, as soon as the prey is seized, it is ripped into pieces.
The 'Tommies' along the railway sometimes make one of these creatures fight with a scorpion. They place the combatants in some slippery vessel so that they can not run out. The scorpion is nearly always much the larger and heavier and has, in addition to its long arms and powerful nippers, a deadly sting. Yet it not infrequently happens that the Jacht Spinnekop comes off victorious, for it seizes the scorpion in its terrible shears and tears a huge hole in it with a quickness and force against which the scorpion is often powerless.
I have a fine large one before me as I write, nearly three inches long (from tip of jaws to end of abdomen), whose jaws alone are more than a quarter of its length, and are, across in front of the eyes, the broadest and solidest part of the whole creature. It is not poisonous; it needs no poison with such terrible jaws.
Passing from the most obvious feature of the Solifugæ, one remarks several other unique characteristics. In spiders, there are, in front of the first pair of legs, two feelers, one on each side of the head, called palps, shorter than the legs, except in very rare instances; in the scorpion, these palps become long arms with powerful nippers at the ends, and there are no delicate feelers; in the Solifugæ, these palps become long, stout and leg-like, with suckers at the ends for holding cr climbing, while there is the very interesting further development that the first pair of legs have ceased to be legs and have become thin, delicate feelers. But there is yet another development, if possible even more interesting still. Along the lower side of the last pair of legs are little white oval plates, supported at regular intervals on short stalks. These delicate little pedestals are sense organs of unknown function; it is possible they are organs of scent, enabling this great hunter to track his prey as he rushes along on the spoor.
Of the Solifugæ I have found some ten or twelve kinds, some belonging to genera hitherto very rare in South Africa. Dœsia is the rarest of the known genera here, and the local species is new. The first male found was only the second of the genus in the South African Museum collection. Dœsia is smallish and of a light, almost transparent, yellowish tint, and nocturnal in its habits. By day one finds them (if lucky enough to do so) under stones. Blossia, of which the species found is also new, is smaller than Dœsia and of a delicate pink color; of these I have found several females, but only one male. Another form is a tiny black one, belonging to an undescribed species and genus, and not more than a quarter of an inch long.
But I pass on to the genus Solpuga, in which the large kinds, diurnal and nocturnal, are found. When one first sees one of them on the veld, especially the commonest (S. chelicornis), one can hardly believe it is not a beautiful karoo flower. This Solpuga is about two inches long (exclusive of legs) when full grown, and of a most brilliant yellow, with a heavy black band down the back of the abdomen, while the legs are covered with long yellow hair, which, in the male, becomes a distinct mane and is iridescent. As it lies on the sand on a hot day, sparkling in the sunshine, it is a most exquisite creature. Touch it, and away it darts; catch it—and take care it doesn't catch you! The male of this Solpuga may be distinguished from the female by two little curved horns, like wires, more than a quarter of an inch long, one on top of each pair of nippers near the points. If you watch a Solpuga closely, you may see its sides palpitating rapidly, even violently if you hold it in your hand. Like all active, high-strung, quick-breathing creatures, the Solifugæ perish almost instantaneously when immersed in spirits, while large scorpions and large Harpactiræ will live for two or three hours. Another Solpuga has a yellow cephalothorax and a red abdomen, another is wholly yellow with spikes on its legs.[1] Very little is known with regard to their methods of reproduction and the nurture of their young. They are great burrowers, but do not make regular holes apparently, and they lie dormant underground during the winter. They are a feature of the thirsty veld and the blazing sun.
Coming now to spiders, and dealing first with the four-lunged group, one may remark that the lung plates are very obvious as four yellowish or pinkish discs on the fore part of the lower side of the abdomen (as are the two discs in the two-lunged genera). The largest here are the Theraphosidæ, known in South Africa by the Dutch name, Baviaan Spinnekoppen (baboon spiders). I have been able to discover only one kind here, a new Harpactira. The adults, with their legs extended, are roughly as large as a man's hand. Their huge bodies and long powerful legs are covered closely with long hair, which is almost identical in color with the hairy coat of a baboon—hence, perhaps, the appropriate name; putting aside the fact that baboons, who turn stones over in search of scorpions and insects of various kinds, are said to be very partial to them. They are poisonous and have very large and powerful fangs directed backwards and subparallel. When these fangs, which ordinarily lie tucked backwards under the cephalothorax, are shot forward and opened apart, the huge hairy spider has a dreadful appearance. The pads on the legs (extending along the lower side of the two end joints and over the tips) are soft and clingy, like the skin of a monkey's hand, and iridescent. Baviaan Spinnekoppen are nocturnal, living by day under stones in burrows, which sometimes end in a hole or a cup-like depression in the ground and are beautifully lined with soft, white silk. Very large spiders are nearly always under large heavy stones; one might almost say that the size of the stone varies as the size of the spider. They prefer the stones on the flats or rands or the boulders at the foot of the kopjes. Occasionally they sink a hole an inch and a half in diameter in the open karoo soil and spin strands of web across its mouth. In one such hole I dug up an adult female with her numerous young, and it was a curious sight to see the young swarming over the great spider. The hole dropped perpendicularly for about six inches and ran at right angles for another foot. The lairs of these spiders are always strewn with bodies of beetles, large and small, eloquent evidences of the sad tragedies that are enacted in insect life. The new Harpactira is common at Hanover, though one does not often find really fine examples of adults. The adult males are rarer than the females, from which they may be distinguished by their slighter bodies and longer legs and by a peculiar pear-shaped spine at the ends of the palps.
We now come to the regular trap-door spiders, the Ctenizidæ, that sink a cylindrical silk-lined tube into the earth and affix a hinged lid to the opening. Of these I have found seven species, all of them, I believe, new. Perhaps the greatest interest gathers round a new Hermachastes. At Cape Town, the representative of this genus has hitherto invariably been found by Dr. Purcell with a trap-door to its hole, but the Hanover species has made a new departure. I have dug up over a hundred, I should think, and have never yet found one with a door. Some have escape blind side chambers, but I have been unable to find a door, either inside or outside. On the contrary, they have the uniform habit of building up a tube with irregular rim, projecting above the ground and varying in height from being just perceptible to a perpendicular regularly cylindrical funnel about an inch and a half high, the average height being more than half an inch. These projecting tubes are built of leaves, pieces of grass or small sticks, and are bound together and lined inside with white web, which extends throughout the length of the underground hole. This habit, as far as regular trap-door spiders are concerned, was, up to this discovery, quite unknown in South Africa; though I believe there are trap-door spiders in northern Africa which apparently build a similar projecting tube. I have not yet found the adult male of this Hermachastes, which probably lives under stones by day—a habit common to the males of this family; but the making of the nest as described has been established with regard to adult females, males up to the last molt, and the young of both sexes.
What has made this spider abandon its trap-door nest and adopt the projecting tube habit? The karoo is dry and dusty and wind swept, and so one can easily understand why an underground, doorless hole should have a projecting funnel; but this will hardly account for the abandoning of the trap-door.
One may note, however, that one of the most common spiders here is a Lycosa (L. subvittata) which sinks a hole in the ground with projecting tube with irregular rim. A trained eye can generally detect the difference between these two nests at a glance, though sometimes even such an eye will be at fault; but, to the untrained eye, the projecting tubes are so much alike that they are, in the majority of cases, indistinguishable. Now, this Lycosa belongs to a wholly different family of spiders, in the two-lunged group; it is a less handsome, smaller spider, pugnacious when handled and remarkably active and wary—unlike Hermachastes, which is slow and dull. Can it be a case of imitation, and that Hermachastes has adopted the habit of building a nest like L. subvittata in a part of the country where this tube-building Lycosa is common all over the veld? The interest deepens, as will be seen, when I come to describe the habits of another Lycosa.
There is another trap-door spider, Hermacha (also a new species), closely allied to Hermachastes, which also has a doorless hole but no projecting tube. Its hole, which is sometimes ten inches deep and beautifully lined with white silk, just ends straight off, level with the surface of the ground. Frequently, however, the opening has a delicate, smoke-like web curtain spun across it, which effectually prevents dust getting into it and bars the way to such enemies as do not dig the spider out. Dr. Purcell thinks this habit may be merely the spider's way of shutting itself in when moulting, but it seems to me to occur too frequently and the inmate to be too lively for the acceptance of such an explanation. Hermacha builds in stiff clayey (brak) soil, which cakes like a stone when dry. When dug up, it shows fight, rearing itself up, raising its legs, and throwing forward and parting its fangs so that a bright red gap is exposed between them. The nest of Hermacha was unknown until I found it here.
Passing by several new and interesting species of this family, we come to perhaps its most representative members, the large spiders that make the largest and strongest doors. Of these I have found three species here, two new Stasimopus and one new Gorgyrella (a new genus, recently named by Dr. Purcell.) These two forms are closely allied and superficially bear a strong resemblance to each other, except that, generally, Stasimopus has a darker cephalothorax and legs. They are slow in their movements, large, with powerful digging teeth and stout, strong, shortish legs. Their silk-lined holes are practically alike, generally dropping almost perpendicularly into the earth for about six to nine inches, with the opening a little larger than the rest of the cylinder; but the doors are different. Stasimopus has a thick cork-like door, with bevelled edge, which fits into the hole, being a little larger at the top than at the bottom. The thickness of the door of Gorgyrella varies; sometimes it is cork-like (though not so thick as the thickest Stasimopus lids), and, at other times, thin and not so firm and solid, in which case its bevelled edge is not so pronounced, and it more overlaps the edge of the hole. The lids of both are always on bare ground, covered with earth, and just flush with the surrounding surface. But there is one essential, and, as far as my experience goes, constant variation in the lids; that of Stasimopus is round, with a slighter hinge, which does not apparently break into the outline of the circle, while that of Gorgyrella is an incomplete circle, more or less D-shaped, with a broad, strong hinge. In the case of both, the silk that forms the hinge is so arranged as to act as an elastic spring which closes the door automatically. (The nest of Gorgyrella was unknown until I found it here, but I have sent some good specimens—as well as many other nests—to the museum, where they may be compared with those of Stasimopus; the spider itself is unrepresented—or at any rate unrecorded—in any European museums.)
It is only the females and young that build these nests; the adult males of the whole family are supposed to live under stones. Both sexes are nocturnal in their habits. The females are common but difficult to find; the males, however, are extremely rare; the male of Gorgyrella has never yet been found. I found one male Stasimopus, which was the second specimen in the South African Museum collection, only one other specimen—that in the British Museum—having been recorded previously. He is hardly recognizable as being what he is, for he is small (about half an inch long), black, with greatly elongated palps. He cuts a very diminutive figure beside his huge and powerful consort.
Among my Gorgyrella finds recently have been two with cocoons and one with young. It would seem that, when the eggs are laid and until the young are strong, the female shuts herself up in the hole; for in all three cases I found the lid closed down securely. The hole containing the mother and young was actually so fastened down that I had to tear it open all round the edge. I am not sure that the other two were also stitched down, but the ground had caked round the edges, effectually fastening them down.
These nests are difficult to discover, indeed almost impossible, except after rain, when, if you know where to look and what to look for, you may find a good many; for the holes being hollow, the lids dry before the surrounding earth and show as lighter colored discs.[2] One needs a little practice, however, even then. The spider is generally at the bottom of the hole, but sometimes, when she hears anything stirring at the lid, she rushes up, digs her claws into it (the lid of Stasimopus has a double circle of holes on the inside, into which the claws are inserted), presses her body against one side of the tube and her legs against the other, and holds the door shut with a strength that is simply amazing. Then you may dig her out easily, by removing only a couple of inches of the tube. If you take the piece of earth which contains the spider holding the door shut, and prod her from the back, she will rush partly out of the door and look around, but she generally keeps a claw of a back leg fixed in the lid, by means of which she can, up to the last moment, withdraw herself again like a flash, so that you may occasionally hear the door slam, if you have good ears and listen carefully! I once hurriedly tried to drag one away while she had her claw fast in the lid, and she parted with her leg rather than lose her last chance of retreat. When she does let go, the door closes of its own accord by means of its spring hinge.
Their chief enemy here is a burrowing animal, a 'mierkat' (Suricata tetradactyla), I think, which destroys a great number of them, discovering them by scent, no doubt.
Some South African trap-door spiders have become climbers. The family Migidæ have, in some instances, become tree trap-door spiders, where they are safe from some of their hereditary enemies and are equally well off for food. They build oval sack-like nests, one to two inches long, under stones or on trees, and cover them externally with "moss, lichens, etc., and place a trap-door at one end—a very interesting adaptation. I have found one new species of the genus Moggridgea here, but have not yet discovered its nest.
Coming now to the two-lunged spiders, with opposite fangs (which comprise the great majority of spiders), a notable one is Latrodectus, which has the most evil reputation in South Africa. It is black with medium long legs and a globular abdomen. (The male is much the smaller and has a thin abdomen.) Fortunately this poisonous spider has a warning color, a red flag showing danger at hand! On the back of the abdomen she has a bright red spot (or spots or stripes). She builds a bell-like nest, about three inches long, in a small bush. At the bottom of the bell, which hangs mouth downwards, the web is very fine and open, and from the mouth radiate web strands. As the webbing approaches the top of the bell, it becomes closer woven, until, for about the last inch or so, it is quite opaque and often covered with small stones, some of them astonishingly large in proportion to the size of the spider, which she has carried up one by one from the ground. There the deadly spider lurks invisible. If you touch the nest, she rushes out, a beautiful creature, with the red patch blazing on her back like fire.
A charming little spider is a Nemoscolus (one of the Argiopidæ), which makes a curled nest just like a tiny bugle, within which she lurks. If you walk over the flats, you will see these little bugles suspended upright, mouth downwards, on the karoo bushes, about a foot from the ground. The 'bugle' is kept in position by means of about five powerful strands, tightly strained in different directions, and from its mouth radiates a beautiful little geometric web, hung over the' ground like a tiny parasol. If you take hold of the bugle, the spider rushes to its mouth, gives a quick glance round, and then drops to the earth like a plumet, where she lies, feigning death, and is by no means easy to discover.
Another genus of the same family is Argiope, which spins a good sized geometric web with a light pyramidal tangle below it. A favorite site is the open mouth of an ant-bear hole. She sits in the middle of the web, back downwards. The abdomen is large, and somewhat flat with deeply serrated edges, and both it and the cephalothorax, which is slight and to some extent overhung by the abdomen, are whitish or whitish-yellow above and darkly speckled brown and yellow below, while the legs are longish and definitely banded. If she' hung back upwards, the white would betray her, but with the lower side up it is wonderful how inconspicuous she is against the ruddy soil of the karoo. If alarmed she shakes the web until it vibrates with astonishing rapidity, so that she becomes merely a haze; and then she drops to the earth, where she either lies still on her back or clings: to a small twig low down, presenting the speckled side to the pursuer, remaining motionless and well hidden.
Yet a third genus of this family may be mentioned. Cyrtophora is often found in prickly pear (Opuntia) hedges. Here she builds a large geometric web with a dense pyramidal tangle below it, both composed of thread of immense strength. The color varies with these spiders and is of considerable beauty. The abdomen is notched above and projects over the cephalothorax to such an extent that the spider has quite a hunch-backed appearance. Like Argiope, she hangs back downwards in the middle of the web, with the pyramidal tangle below her. The threads of her web and tangle are so strong and the prickly pear hedges are at times so densely covered with them that the long stick with which one plucks the sweet ripe fruit often becomes so coated with the powerful strands and so impeded thereby that it cannot be used effectively till cleaned.
Selenops, one of the Clubionidæ, is notable for the lightning-like rapidity of its movements. It is a singularly flat spider of a speckled reddish-brown color, almost exactly like that of the dolerite rocks on the kopjes where it is found. Its legs are long and distinctly banded, giving the whole spider a mottled appearance. When you turn up a stone under which it is, you will find it, clinging back downwards to the lower side. The moment it becomes alarmed it begins to run, sidewise, with a circular motion, first in one direction, then in another, with such astounding rapidity that it becomes just a blur on the stone; and then it flashes sidewise over the edge.
We come now to perhaps the most interesting finds, which concern two of the Lycosidæ and one of the Eresidæ.
It was long held to be an established fact that no two-lunged spiders were trap-door makers; even up to the present, it seems that only a couple of instances had been observed of two-lunged spiders constructing trap-doors to their nests, and these only in the family Lycosidæ (one in South Africa, one in North Africa and one in Russia). But the finds at Hanover have clearly established the trap-door habit as a regular thing in the case of two species of South African Lycosidæ (one of which may or may not be identical with L. domicola, the South African instance above referred to) and one species of Eresidæ. I have found many of these nests and have sent specimens to the South African Museum.[3]
The Lycosidæ are numerous and common throughout South Africa. One finds them in great numbers under stones, in the projecting tube nests and running about the veld. I have found fourteen species here, varying greatly in color and shape, and in size from one eighth of an inch to about an inch in length. Ten of these are new.
Lycosa subvittata has already been mentioned as building the nest with projecting tube, closely resembling that of the new Hermachastes. The underground holes of these two nests differ considerably, mainly perhaps in the fact that, whereas that of Hermachastes is regularly cylindrical and beautifully white-silk-lined throughout, that of L. subvittata is not silk-lined at all but only brown-webbed for about an inch at the top and is not regularly cylindrical. It is not, however, necessary to compare the holes in detail here; the interest is now in connection with the web-lined, irregularly rimmed, projecting tubes, whose essential differences may be briefly noted. The tube of the Lycosa is generally shorter, greater in diameter and untidier in appearance than that of the Hermachastes, and, while it often slants gapes and is not a true cylinder, that of the Hermachastes is neat, upright and regularly cylindrical. But the nests frequently occur side by side in the same ground and are almost identical in appearance. For instance, I recently found a nest of the Lycosa whose projecting tube was two inches high and so like that of the Hermachastes that I had to dig it up to ascertain for certain which spider was the builder.
Thus we have the interesting fact that a true trap-door spider here has abandoned its trap-door making and adopted the projecting tube habit characteristic of a Lycosa common to this part of the country; while, on the other hand, we have the equally interesting fact that two species of Lycosa have abandoned the habits of their tribe and family and have become regular trap-door makers.
The commoner and smaller of these two trap-door Lycosæ is a very alert, often ruddy, spider with banded legs. It makes a hole which is generally a true cylinder and deeper than the hole of L. subvittata, and at the opening it always has a door. The doors are thin lids, firm, cup-like in shape, and are attached to the rim of the hole by several almost invisible strands of web. So delicate are these strands (which serve as a hinge, being affixed at several points to the edge of the lid), that I almost invariably move the lid with the point of my knife to ascertain whether it is fixed; for it sometimes comes loose and lies at varying short distances from the mouth of the hole (remaining in use all the time apparently—though of this I am not quite sure). The spider closes the lid in the heat of the day, with the concave, web-lined side down, and opens it late in the afternoon and early in the morning, but so late and so early that it may be said to be open only during the night; though, before the weather became very hot and dry, it was common to see small lids open during the day. Sometimes the lid is attached, on the upper side, to a stone or stick or leaf, but generally it is just covered with earth and lies almost flush with the ground. It is practically undiscoverable when closed. It may be noted that the trap-door Lycosa is apparently (perhaps only when young) not wholly nocturnal, and that many have been found under stones, also that the adult male is as much a trap-door maker as the female, and that, when the spider comes from the hole, it opens the door and leaves it lying beside the opening with concave side up—all habits which are certainly not shared by the Ctenizidæ and are apparently peculiar to itself.[4]
The Lycosidæ are an interesting family in other respects. The female, when about to lay her eggs, makes a neat cup with circular rim, in which she deposits her eggs, heaped up. She then makes a similar cup which she inverts over them, after which she encloses the eggs between them by soldering them together round the rims. The whole ball of eggs is then spun over with whity-brown silk and attached to the spinners at the end of the abdomen, to be carried about till the young emerge, which crawl out and on to the mother's back, where they remain in a great cluster and are carried about by her for several weeks. She presents an odd spectacle as she rushes about with her numerous progeny on her back.
The Lycosidæ as a family are rovers and do not make regular nests, and this is why the females carry first the egg sacks and then the young about with them. But it is interesting to note that the habit of attaching the egg sack to the spinners (and no doubt also of carrying the young about) persists in the projecting-tube builder and in the trap-door species, although the paramount necessity for doing so apparently no longer exists.
The female Lycosa is said to be often curiously dainty about the color of the silk she uses for the inner cup; it is frequently of some bright color, say orange, while the rims are cemented with silk of some other gay color, say bright green. Sometimes she uses as many as four different colors. But, after all this trouble, she has to cover up her gaudy and attractive cocoon with some dull-covered silk, so as not to attract the notice of flies and wasps on the lookout for a nest of fat eggs in which to deposit an egg or two of their own.
My finds in Eresidæ cover five species. Several of them, belonging to Eresus and Dresserus, found under stones in dense tangles of web, are very slow in their movement and feign death when exposed; one of them is a large creature with an abdomen nearly an inch long and half an inch broad, resembling a huge cattle tick in shape and color (a brownish or bluish slate), even to the puncture-like marks on the back. Of the other species, one is Stegodyphus; you may see their dense ball-like yellow nests on the karoo bushes, with powerful strands binding them in all directions. At least one species of Stegodyphus is social, but the local form lives solitary or in pairs.
Another is perhaps the most interesting Hanover find. A neighboring Dutch farmer (who carefully obtains the Latin name of every species he brings, and who has been a most useful contributor) asked me if I knew of a small 'licht bruin' (light brown) spider that made a double door. Neither I nor any one else, so far as I know, had ever heard of such a thing. But my friend was not far wrong. Where there are ijzer-kopjes (kopjes of dolerite boulders) there are generally, somewhere on the gentle slopes of the flat at the foot, patches of gritty red sand, composed largely of the disintegrated dolerite. The sand is loose and desert-like for about two inches in depth, after which it meets sand finer in grain and baked hard. The larger grit lies on the surface. If you look carefully at these patches, you may see a delicate outline, shaped like a butterfly's wings, traced on the red sand, one pair of 'wings' being generally larger than the ether, as is the case with a real butterfly. The impression is very beautiful and fairy-like. These 'wings,' which are covered with gritty red sand and lie flush with the surface of the ground, are generally about an inch and a quarter square, the longest measurement being across the front pair. If you insert the blade of your knife under the smaller wings, you may turn the lid over its hinge, which is on the side of the larger pair. This needs to be done carefully, for the lid is limp and delicate and easily doubles up and loses it shape; the operation is somewhat suggestive of tossing a pancake. You expose a smooth bare spot, shaped like the double wings, nearly in the middle of which is the hole.
Though this butterfly lid is about an inch and a quarter square, the hole is hardly, if anything, more than an eighth of an inch in diameter. It is situated almost under the middle of the lid, just below what corresponds to the thorax of the butterfly. The lid is attached to the side of the hole towards the head of the butterfly, and the attachment is restricted to the width of the thorax, leaving the whole outline of the wings free. The hole, which is from two to three inches deep and beautifully brown-webbed throughout, runs straight into the ground at an acute angle under the hinge. The side of the opening opposite the hinge slants, and on the slant, attached to the web lining of the hole, lies a small, loose, felt-like flap.
Median Section of Nest of New Trapdoor Eresid. A-A′, Extent of lid across hole; C-C′, Extent of 'wings' on each side of hole; A, Where hinge is affixed; B, Flaps; a Blind side chamber. It must be remembered that the large 'butterfly' lid is never raised—indeed, cannot be raised—by the spider; for she is not strong enough, and, if she were, it would double up and lose its shape. So it always remains flat on the ground, covering the hole and the ground for more than half an inch all around it. The spider creeps in and out underneath, as from under a blanket; you can trace its passage by a little wave rippling along under the sand-covered wings. The flap, I think, has two purposes. First, it affords the little spider a means of easy ingress and egress to the hole under the lid; it is firm and felt-like to give the spider a good hold for her feet over the loose shifting sand, and it is slanting to enable her gradually to overcome the downward pressure of the large lid; if the hole were perpendicular, the spider would have difficulty in levering herself over the edge against the weight of the lid, and, if the exit were not slanting and there were no flap, the loose, gritty sand would give way under her feet as she strove to get out. The little felt-like flap leads her gradually on to level ground, where she can easily make her way in any direction to the edge of the lid.
Secondly, the flap can, in case of necessity, serve as a make-shift door. If you tear the lid off and wait a little while, you will see the front legs of the spider emerge at A and pull at any fragment of hinge left, in order to close the hole temporarily; if she fails at this, she will pull up the flap, which, as I have said, is loose and just long enough to close and conceal the hole admirably. It is interesting to note that the spider always comes up facing A, which results in her being pretty well concealed while closing the hole; whereas, if she came up facing B, the slant would, to a considerable extent, expose her. This would seem to indicate that the flap is resorted to as a make-shift door only if the spider finds there is not enough web for the purpose left from the torn-off hinge.
Sometimes if you sit and watch an undisturbed nest, you will see the large 'butterfly' lid tremble, and then you will see the points of the little legs appear at the edge as the spider throws out the remains of a small ant or fly or some grains of sand. If you then quickly remove the lid, she will pop round and hide under it on the open ground. If exposed she lies perfectly still with her legs drawn in, feigning death, and may be handled like a dead thing. As she is very much the color of the loose sand, it is quite common to miss her, unless great care be taken.
It will be seen that this wonderful little spider is far ahead of the trap-door Lycosa in the complexity of her nest; but we have not yet reached the limit of her intelligence. Often she builds a beautifully webbed blind side-chamber, about half way down the hole, into which she escapes, and which, when the sand is disturbed, collapses over her and enfolds and hides her. I did not find the side chamber till I sought for it carefully. It is a late development, and shows she is no mere brilliant amateur like the Lycosa.
The trap-door eresid never, as far as I know, leaves the nest during the day, and certainly never opens the door, but creeps in and out under it, thus always leaving it closed. Neither do the adult males make doors or live under ground. Digging shows females, adult and young in the nests, but males only up to the last molt.
Here again comes a new and very interesting departure on the part of the eresid. The male, which, for all practical purposes, is, up to the last molt, identical with the female in size, color and shape, becomes quite another being in every respect afterwards. The female and immature males and young have a light brown cephalothorax and legs and a smoky abdomen, the colors being not widely different. But, after the last molt, the male is simply unrecognizable. He emerges a handsome, very alert creature, that runs about openly by day—a habit I think unknown in the Ctenizidæ. His magical change is no less radical in character than in appearance. His cephalothorax and legs are black, except that the front pair of legs, which are considerably elongated, have the fore parts white; his abdomen is black underneath, with a thin band of black round the sides, while the upper part is bright yellow. He moves alertly, often in a series of short rushes, and, if interfered with, does not feign death, like the rest of the eresidæ, but fights promptly and viciously, raising his body in front, lifting his forelegs on high and shaking the white parts angrily at you. To anything near his size he must be a most terrifying object.
Now, why this wonderful change in appearance and habits? Why he has adopted the habit of running about by day, I do not know. But, having done so, I cannot help thinking that his changed appearance and habits may have been evolved as a protection to him. At the time of the year when he appears, a very vicious ant (Camponotus fulvipilosus) is common over the veld during the day. The adult male eresid closely resembles this ant in color and style of movement. The ant, like the eresid, has a black head, thorax and legs and a yellow abdomen, and it moves in rushes. The resemblance is so close that, when I first saw the eresid, I took it, for a moment, to be the ant, and when I sent it to Dr. Purcell I described it as 'ant-like.'
No such spider as this eresid was previously known in South Africa. Dr. Purcell says it forms a new genus. I have sent several of its nests in situ to Cape Town. This could be done sucessfully only by melting hard paraffin and then pouring it into the sand around the nest, letting it soak up to the lid. Then, when the paraffin had hardened in the sand and bound it together, the nest could be removed in perfect order. The paraffin may be removed from the lid by treating it with warm oil of turpentine. Dr. Purcell will some day give detailed descriptions of all the interesting spiders and other things I have chatted about, with sketches of them and the nests in situ, and then we shall be able to call them by the names they will receive from him. Meanwhile I have thought a popular account of some Hanover arachnids might prove interesting.
- ↑ These two species, and possibly one or two others, are probably new, but this cannot be determined for certain until the males are caught, and, aa yet, I have caught only the females.
- ↑ This method was suggested by Mr. Charles Groom.
- ↑ It is remarkable that, while I was laying the facts of the first trap-door Lycosa before Dr. Purcell, he should have established at Cape Town the trapdoor habit in the case of Cydrela, one of the Zodariidæ, another two-lunged family.
- ↑ I have described the commoner trap-door Lycosa, because I have had greater opportunities of observing it; but, as far as my observation goes, the description applies equally to the larger and less common trap-door species.