tropical insects, spiders, and scorpions.
gradual increase of insect life on advancing towards the line—the hercules beetle—the goliath—the inca beetle—the walking-leaf, and walking-stick insects—the soothsayer—luminous beetles—tropical spiders—their gaudy colours—trap-door spiders—enemies of the spiders—mortal combat between a spider and a cockroach—tropical scorpions—dreadful effects of their sting.
on advancing from the temperate regions to the line, we find the insects gradually increasing with the multiplicity of plants, and at length attaining the greatest size, brilliancy of colour, and variety of form in those tropical lands where moisture combines with heat in covering the ground with a dense and everlasting vegetation. our largest insects are indeed mere pygmies when compared with their tropical relatives. we have no tiger-beetle to equal the ferocious mantichora of south africa, which, hiding beneath stones from the terrible glare of the sun, darts quickly from its place of concealment upon its ill-fated prey; nor a stag-beetle of the size of the odontolabris cuvera of china and northern india. our largest dung-feeding lamellicorns look but small near the african copris hamadryas; and our cockchafer, though conspicuous among our native insects, is a dwarf when confronted206 with the leucopholis bimaculata of india, which, if it be voracious in proportion to its size, must destroy a vast amount of vegetation in the course of its long larval existence. the goliath beetles of the coast of guinea, are truly deserving of their name, and in torrid america the colossal hercules beetle attains a length of five, or even six inches. though but little is yet known of its economy, it most likely subsists upon putrescent wood, and evidently leads a tree life, like its relations—the elephant, the neptune, the typhon, the hector,207 and the mars beetles—whose very names indicate that they are ‘first-rate liners’ in the insect world. all these beetles excavate burrows in the earth, where they conceal themselves during the day, or live in the decomposed trunks of trees, and are generally of a dark rich brown or chestnut colour. on the approach of night they run about the footpaths in woods, or fly around the trees to a great height with a loud humming noise. resembling the large herbivorous quadrupeds by their comparative size and horn-like processes, they are still further like them in their harmless nature, and thus deserve in more than one respect to be called the elephants among the insect tribes.
odontolabris cuvera.
copris hamadryas.
leucopholis bimaculata.
many of the tropical dragon-flies, grasshoppers, butterflies, and moths are of no less colossal dimensions in their several orders than the giants among the beetles. the libellula lucretia, a south american dragon-fly, measures five inches and a half in length, and the cinnamon-eating atlas-moth of ceylon often reaches the dimensions of nearly a foot in the stretch of its superior wings. the names of many other species conspicuous by their size might be added; but these examples suffice to show the enormous proportions attained by insects in the warmer regions of the globe.
in the tropical zone, where the prodigality of life multiplies208 the enemies which every creature has to encounter, we may naturally expect to find the insects extremely well provided with both passive and active means of defence.
many so closely resemble in colour the soil or object on which they are generally found, as to escape even the eye of a hungry enemy. the wings of several brazilian moths appear like withered leaves that have been gnawed round their margins by insects; and when these moths are disturbed, instead of flying away, they fall upon the ground like the leaf which they resemble, so that it is difficult, if not impossible, on such occasions to know what they really are.
phyllium.
the illusion is still more complete when the likeness of form is joined to that of colour, as in the walking-leaf and walking-stick insects. some, of an enormous length, look so exactly like slender dead twigs covered with bark, that their insect nature can only be discovered by mere accident—upon being handled they feign death, and their legs are often knobbed, like the withered buds of trees; some resemble living twigs, and are green; others such as are decayed, and are therefore coloured brown; the wings of many put on the resemblance of dry and crumpled leaves, while those of others are vivid green—in exact accordance with the plants they respectively inhabit. this highly remarkable family consists of the herbivorous phasmas and phylliums—the former of which have a thin twig-like shape, while the latter have an enlarged body—and of the carniverous mantides, or soothsayers. as the mantis is slow and without much muscular energy, and its organisation requires a large supply of food, nature has disguised it under the form of a plant, the better to deceive its victims. like a cat approaching a mouse, it moves almost imperceptibly along, and steals towards its prey, fearful of putting it to flight. when sufficiently near, the fore legs are suddenly darted out to their full length, and seize the doomed insect, which vainly endeavours to extricate itself; the formation of the fore leg enabling the tibia to be so closed on the sharp edge of the thigh as to amputate any slender substance brought within its209 grasp, and to make even an entomologist repent a too hasty seizure of his prize.
the mantis, by the attitude it assumes when lurking for its prey or advancing upon it—which is done by the support of the four posterior legs only, whilst the head and prothorax are raised perpendicularly from the body, and the anterior legs are folded in front—greatly resembles a person praying. hence, in france it is called le prêcheur, or le prie dieu; the turk says it points to mecca; and several african tribes pay it religious observances. in reality, however, its ferocity is great, and the stronger preying on the weaker of their own species, unmercifully cut them to pieces.
mantis.
within the space of a week, professor burmeister saw a mantis devour daily some dozens of flies, and occasionally large grasshoppers and young frogs, consuming, now and then, lizards three times its own length, as well as many large fat caterpillars. hence it may be judged what ravages these strangely-formed creatures must cause among all weaker beings which incautiously approach them, and that, far from being the saints, they are, in reality, the tigers of the insect world. among the organic marvels of the innocent herbivorous phylliums, their seed-like eggs must be mentioned; for the wonderful provision of nature in giving the parents a plant-like form extends even to their progeny, in order to secure them from similar dangers. though generally tropical, yet van diemen’s land possesses a gigantic walking-stick, or phasma, the body of which is eight inches long; and the mantis religiosa is found all over southern europe.
the leaf-like form which renders the phylliums one of the wonders of entomology, appears likewise in other insects. thus, in the diactor bilineatus, a native of brazil, the hind legs have singular leaf-like appendages to their tibial joints; and in the javanese mormolyce, a beetle remarkable for its extreme flatness and the elongation of its head, we find the upper wings spreading out in the form of broad leaves.
the long hairs, stiff bristles, sharp spines, and hard tubercular prominences with which many caterpillars are bristled210 and studded, are a most effectual means of defence, and often prove a grievous annoyance to the entomologist, from their poisonous or stinging properties. mr. swainson once finding in brazil a caterpillar of a beautiful black colour, with yellow radiated spines, and being anxious to secure the prize, incautiously took hold of it with the naked hand; but so instantaneous and so violent was the pain which followed, that he was obliged to return home. every device that could be thought of to allay the itching produced by the venomous hairs of this creature were in turn resorted to, with little or no effect for several hours, nor had it entirely ceased on the following morning.
javanese mormolyce.
though the great majority of luminous animals are marine, frequently lighting up the breaking wave with millions of moving atoms, or spreading over the beach like a sheet of fire,20 yet several insects are also endowed with the same wonderful property. the european glow-worms and fire-flies, sparkling on the hedge-rows, or flying in the summer air, afford a charming spectacle; but their brilliancy is far surpassed by that of the phosphorescent beetles of the torrid zone. thus the cocujas of south america, which emits its light from two little transparent tubercles on the sides of the thorax, glows with such intensity that a person may with great ease read the smallest print by the phosphorescence of one of these insects, if held between the fingers and gradually moved along the lines with the luminous spots above the letters; but if eight or ten of them are put into a phial the light will be sufficiently good to admit of writing by it.
cocujas.
the indian archipelago is equally rich in luminous insects. the podada tree, the ornament of most of the river banks of borneo, has a remarkably elegant foliage of a light green colour. rajah brooke21 describes these trees illuminated by the fire-flies211 in countless numbers as a most enchanting sight, and resembling a fire-work by the constant motion of the light. on the samarahan he sometimes saw each side of the river lit by a blaze of these beautiful little insects.
in the woods of sarawak mr. adams observed a splendid glow-worm (lampyris), each segment of the body illuminated with three lines of tiny lamps, the luminous spots on the back being situated at the posterior part of the segmentary rings on the median line, while those along the sides of the animal were placed immediately below the stomates or spiracula, each spiraculum having one bright spot. this very beautiful insect was found shining as the darkness was coming on, crawling on the narrow pathway, and glowing among the dead damp wood and rotten leaves. when placed around the finger, it resembled in beauty and brilliancy a superb diamond ring.
the sparkling effulgence of the tropical elaters is frequently made use of by the fair sex, as an equally singular and striking ornament. the ladies of the havana attach them to their clothes on occasions of festivity, and the indian dancing girls often wear them in their hair.
in prescott’s ‘conquest of mexico’ we are told that, in 1520, when the spaniards visited that country, the wandering sparks of the elater, ‘seen in the darkness of the night, were converted by their excited imaginations into an army with matchlocks;’ and on another occasion these phosphorescent insects caused british troops to retreat: for when sir john cavendish and sir robert dudley first landed in the west indies, and saw at night an innumerable quantity of lights moving about, they fancied that the spaniards were approaching with an overwhelming force, and hastily re-embarked before their imaginary foe.
a creature, half of whose body is generally fixed to the other by a mere thread, whose soft skin is unable to resist the least pressure, and whose limbs are so loosely attached to the body as to be torn off by the slightest degree of force, would seem utterly incapable of protecting its own life and securing that of its progeny. such, however, is the physical condition of the spiders, who would long since have been extirpated if nature had not provided them with the power of secreting two212 liquids, the one a venom ejected by their mandibles, the other of a glutinous nature, transuded by papillæ at the end of their abdomen. these two liquids amply supply the want of all other weapons of attack or defence, and enable them to hold their own against a host of enemies. with the former they instantly paralyse insects much stronger and much more formidable in appearance than themselves; while with the latter they spin those threads which serve them in so many ways—to weave their wonderful webs, to traverse the air, to mount vertically, to drop uninjured, to construct the hard cocoons intended to protect their eggs against their numberless enemies, or to produce the soft down which is to preserve them from the cold.
preying on other insect tribes, which they attack with the ferocity of the tiger, or await in their snares with the patient artifice of the lynx, the spiders may naturally be expected to be most numerous in the torrid zone, where nature has provided them with the greatest abundance and variety of food. there also, where so many beetles, flies, and moths attain a size unknown in temperate regions, we find the spiders growing to similar gigantic dimensions, and forming webs proportioned to the bulk of the victims which they are intended to ensnare.
in some parts of makalolo, dr. livingstone saw great numbers of a large beautiful yellow-spotted spider, the webs of which were about a yard in diameter. the lines on which these webs were spun, extended from one tree to another, and were as thick as coarse thread. the fibres radiated from a central point, where the insect waited for its prey. the webs were placed perpendicularly, and a common occurrence in walking was to get the face enveloped in them, as a lady is in a veil.
by means of their monstrous webs many giant-spiders of the tropical zone are enabled to entangle not only the largest butterflies and moths, but even small birds. some mexican species extend such strong nets across the pathways, that they strike off the hat of the passer-by; in senegal spiders spin threads so strong as to be able to bear a weight of several ounces, and in the forests of java, sir george staunton saw spider-webs of so strong a texture that it required a sharp knife to cut one’s way through them; and many other similar examples might be mentioned.
213 these large spiders so temptingly suspended in mid-air in the forest glades, seem very much exposed to the attacks of birds, but in many cases it has pleased nature to invest them with large angular spines sticking out of their bodies in every kind of fashion. some are so protected by these long prickles that their bodies resemble a miniature ‘chevaux de frise,’ and could not by any possibility be swallowed by a bird without producing a very unpleasant sensation in his throat. one very remarkable species (gasteracantha arcuata) has two enormous recurved conical spines, proceeding upwards from the posterior part of the body, and several times longer than the entire spider.
other araneæ, to whom these means of defence have been denied, are enabled by their colour to escape the attacks of many enemies, or to deceive the vigilance of many of their victims. thus, those that spend their lives among the flowers and foliage of the trees are, in general, delicately and beautifully marked with green, orange, black, and yellow, while those which frequent gloomy places are clothed with a dark-coloured and dingy garb, in accordance with their habits. in the forests about calderas, in the philippine archipelago, mr. adams saw handsomely coloured species of theridia crouching among the foliage of the trees: while numbers of the same genus of a black colour were running actively about among the dry dead leaves that strewed the ground, looking, at a little distance, like odd-shaped ants, and no doubt deceiving many an antagonist by this appearance. one species, which knew it was being watched, placed itself upon a diseased leaf, where it remained quite stationary until after the departure of the naturalist, who, had he not seen the sidelong movement of the cunning little creature in the first instance, would not have been able to distinguish its body from the surface of the leaf. while, in this case, dulness of colour served as a defence, the vividly-coloured spiders that live among the foliage and flowers no doubt attract many flies and insects by reason of their gaudily-tinted bodies.
one of the most remarkable instances of the harmony of colour between the araneæ and their usual haunts was noticed by mr. adams among dense thickets formed by the abrus precatoria, where he found a spider with a black abdomen marked214 on each side with scarlet, thus resembling the colours of the seeds of the abrus, so well known to children under the name of ‘black-a-moor beauties.’
an exception to the general rule is, however, found in those very large and powerful species which, if not rendered somewhat conspicuous to the sight of other insects, might do too much damage to the tribes which they keep in check. most of these, therefore, have the thorax and abdomen margined with a light colour that contrasts strongly with that of their bodies, and, in many cases, gives timely warning of their approach.
the european spiders have generally a very repulsive appearance, while many of the tropical species are most splendidly ornamented, or rather illuminated, many of them by the vividness of their colours resembling the gaudy missals painted by monks in the middle ages. thus, among the epeiras of the philippine islands, are found white figures on a red ground; red, yellow, and black, in alternate streaks; orange marbled with brown, light green with white occelli, yellow with light brown festoons, or ash-coloured and chestnut bodies with crescents, horse-shoes, chinese characters, and grotesque hieroglyphics of every description. unfortunately, these colours, lustrous and metallic as the feathers of the humming-bird, are, unlike the bright colours of the beetle, totally dependent on the life of the insect which they beautify, so that it is impossible to preserve them.
while most spiders obtain their food either by patiently waiting in ambush or by catching it with a bound, the enormous mygales, or trap-door spiders, run about with great speed in and out, behind and around every object, searching for what they may devour, and from their size and rapid motions exciting the horror of every stranger. their body, which sometimes attains a length of three inches, while their legs embrace a circle of half a foot in diameter, is covered all over with brown, reddish brown, or black hair, which gives them a funereal appearance, while their long fangs armed with sharp hooks proclaim at once what formidable antagonists they must be to every insect that comes within their reach. though some species are found in southern europe, in chili, or at the cape, yet they are chiefly inhabitants of the torrid zone, both in the old215 and the new world. some of them weave cells between the leaves, in the hollows of trees or rocks, while others dig deep tubular holes in the earth, which they cover over with a lid, or rather with a door formed of particles of earth cemented by silken fibres, and closely resembling the surrounding ground. this door or valve is united by a single hinge to the entrance at its upper side, and is so balanced that, when pushed up, it shuts again by its own weight; nay, what is still more admirable, on the interior side opposite to the hinge a series of little holes may be perceived, into which the mygale introduces its claws to keep it shut, should any enemy endeavour to open it by force. the interior of the nest, which is sometimes nine inches deep, is lined with a double coat of tapestry, the one nearest the wall, which is of a coarser tissue, being covered with a pure white silken substance like paper.
new-comers into the country which the trap-door spider inhabits, are often as surprised as ali baba in the ‘forty thieves’ by seeing the ground open, a little lid lifted up, and a grim black-haired spider peer about as if to reconnoitre the position before sallying out of its fortress. at the least movement on the part of the spectator, down drops the spider disappearing into its hole, the door closes and the astonished observer, unable to find its traces in the apparently unbroken soil doubts whether his eyes have not deceived him. nothing short of actual violence will induce the trap-door spider to vacate the premises it has so admirably constructed. it holds on with all its might and will permit the earth to be excavated around its burrow and the whole nest to be removed without deserting its home. but all its energy vanishes as soon as it is removed from the burrow it so pertinaciously defended; it then loses all its activity, remains fixed to the spot as if stupified, or at the best walks languidly about like one who has lost all that made existence valuable.
at caldera, mr. adams observed a dingy little species of spider of the genus clubiona, concealing itself in very snug retreats formed out of a dead leaf, rolled round in the shape of a cylinder, lined with a soft silken tissue, and closed at one end by means of a strong woven bolt-door. when hunted, it was amusing to see the frightened little creatures run for protection into their tiny castles, where they would doubtless216 be safe from the attacks of birds, owing to the leaves not being distinguishable from others that strew the ground.
all species of spiders are gifted with an admirable maternal instinct, and resort to various methods for the purpose of securing their cocoons. the theridion, when a seizure of the precious burden is threatened, tumbles together with it to the ground, and remains motionless, while the thorinsa covers it with its body, and when robbed of it, wanders about disconsolate. in a forest of the sooloo islands, mr. adams found the ground literally overrun with a small black agile species of lycosa, many of which had a white flattened globose cocoon affixed to the end of their abdomen. it was most amusing to watch the care with which these jealous mothers protected the cradles of their little ones, allowing themselves to fall into the hands of the enemy rather than be robbed of the silken nests that contained them.
if the spiders are at war with all other insects, and contribute to keep them within bounds by the destruction they cause among their ranks, they in their turn are sorely persecuted creatures. monkeys, squirrels, lizards, tortoises, frogs, and toads catch and devour them wherever they can. in java and sumatra, we even find a family of sparrows named arachnotheræ, from their living almost exclusively on spiders. armed with a prodigiously long recurved and slender beak, these birds know how to pursue them and drag them forth from the most obscure recesses.
it is amongst the insects, however, that the spiders have to fear their most numerous and formidable enemies. independently of those which they find in their own class, the centipedes seize them beyond the possibility of escape; and several species of wasps, more savage and poisonous than themselves, will rush upon spiders eight times their size and weight, and benumbing them with a sting, bear them off to their nests, to serve as food for their larvæ.
others attack the spiders in their progeny. the pimpla arachnitor pierces with its invisible gimlet the tender skin of the spider’s egg, and, without tearing it, introduces its own eggs into the liquid. the pimpla’s egg soon comes to maturity, and the larva devours the substance of that of the spider, from whence a winged insect bursts forth—a phenomenon which made some naturalists, too hasty to judge from217 appearances, believe that spiders were able to procreate four winged flies.
notwithstanding the disgust or horror which they generally inspire, the spiders are, with very rare exceptions, by no means injurious to man. however promptly their venom may act upon insects, even that of the largest species of northern europe produces, on coming into contact with our skin, no pain or inflammation equalling in virulence that of the wasp, the bee, the gnat, or other insects of a still smaller size. the giant spiders of a sunnier sky, armed with more formidable weapons, naturally produce a more painful sting; but even here the effects have been much exaggerated.
in the country of the makalolo, dr. livingstone, feeling something running across his forehead as he was falling asleep, put up his hand to wipe it off, and was sharply stung, both on the hand and head; the pain was very acute. on obtaining a light, he found that it had been inflicted by a light-coloured spider about half an inch in length; but one of the negroes having crushed it with his fingers, he had no opportunity of examining whether the pain had been produced by poison from a sting, or from its mandibles. no remedy was applied, and the pain ceased in about two hours.
if thus, among the many species of spiders, hardly a single one may be said to be formidable to man, the indirect services which they render him—by diminishing the number of noxious insects—are far from inconsiderable.
in several countries where insects cause great ravages, the services of the spiders are duly appreciated. thus in the west indies, a large and formidable trap-door spider, which would make a european start back with horror, is looked upon with pleasure by the islanders of the torrid zone, who respect it as a sacred animal, by no means to be disturbed or harmed, as it delivers them from the cockroaches, which otherwise would overrun their dwellings. those who do not possess these spiders take good care to purchase and transport them into their houses, expecting from them similar services to those we derive from a good domestic cat. the spectacle of a trap-door spider bounding on a cockroach, with all the ferocity of a tiger springing on its prey, would no doubt have all the interest of a bull-fight if the diminutive size of the combatants were swelled218 to more ample proportions. mr. e. layard has described one of these encounters which he witnessed near a ruined temple in ceylon. when about a yard apart, each of the enemies discerned the other and stood still, the spider with his legs slightly bent and his body raised, the cockroach confronting him, and directing his antennæ with a restless undulation towards his enemy. the spider, by stealthy movements, approached to within a few inches, and paused, both parties eyeing each other intently; then suddenly a rush, a scuffle, and both fell to the ground, when the blatta’s wings closed; the spider seized it under the throat with his claws, and when he had dragged it into a corner, the action of his jaws was distinctly audible. next morning, mr. layard found the soft parts of the body had been eaten, nothing but the head, thorax, and elytra remaining.
scorpion.
the scorpions, which even in europe are reckoned among the most malignant insects, are truly terrific in the torrid zone, where they frequently attain a length of six or seven inches. closely allied to the spiders, their aspect is still more repulsive. were one of the largest scorpions menacingly to creep up against you, with extended claws and its long articulated sharply-pointed tail projecting over its head, i think, despite the strength of your nerves, you would start back, justly concluding that a creature of such an aspect must necessarily come with the worst intentions. the poison of the scorpion is discharged like that of the snake. near the tip of the crooked sting, namely, which terminates the tail, we find two or three very small openings, through which, on pressure, the venom of the gland with which they are connected immediately issues forth. by means of this weapon, even the small european scorpions are able to kill a dog, while the tropical giants of the race inflict wounds that become fatal to man himself. the sting of several south american scorpions produces fever, numbness of the limbs, tumours on the tongue, weakness of the sight, and other nervous symptoms, lasting twenty-four or forty-eight hours; but the african scorpions seem to be still more formidable. mr. swainson informs us that the only means of saving the lives of our219 soldiers who were stung by those of egypt, was the amputation of the wounded limb; and professor ehrenberg, who, while making his researches on the natural history of the red sea, was stung five times by the androctonus quinquestriatus, and funestus, says he can well believe, from the dreadful pains he suffered, that the poison of these scorpions may become fatal to women and children.
scorpions, being intolerant of light, creep by day into every hole or corner that can shelter them from the unwelcome sunbeams, and often cause very great annoyance by this custom. no traveller in a scorpion-infested country who has learnt by experience the habits and dangerous character of these creatures will retire to rest before having carefully examined his bed, especially taking up the pillow, to ascertain that no enemy is lurking within the folds of the bedding. shoes, boots, and gloves are also favourite resorts of the scorpion, a circumstance which has caused many a serious accident.
the burrows of this formidable animal can always be detected by the semilunar form of the entrance, exactly fitting the outline of the animal which digs it. to force them to quit the premises nothing more is required than to pour in some water, when the disturbed inmate rushes furiously out, his pincers snapping wildly at the enemy.
the suicidal propensities of the scorpion, when, inclosed by a fiery circle, it finds escape impossible, have been often mentioned in prose and poetry, and form among others the subject of a beautiful simile in byron’s ‘giaour’:—
the mind, that broods o’er guilty woes, is like the scorpion girt by fire, in circle narrowing as it glows, the flames around their captive close, till, inly searched by thousand throes, and maddening in her ire, one sad and sole relief she knows, the sting she nourish’d for her foes, whose venom never yet was vain, gives but one pang, and cures all pain, and darts into her desperate brain: so do the dark in soul expire, or live like scorpion girt by fire.
the voluntary death of the animal is doubted by many, who maintain that the position of the sting when turned towards220 the head, is merely a convulsive movement; but the opinion of those who are inclined to bring in the verdict ‘felo de se’ is corroborated by captain pasley, r.a., who repeatedly tried the experiment of surrounding the scorpion with a ring of fire, and invariably found that it had stung itself to death. the fiery circle was about fifteen inches in diameter and composed of smouldering ashes. in every instance the scorpion ran about for some minutes, trying to escape, and then deliberately bent its tail over its back, inserted the point of its sting between two of the segments of his body and speedily died. the heat given out by the ashes was very trifling and not equal to that which is caused by the noontide sun, a temperature which the scorpion certainly does not like, but which it can endure without suffering much inconvenience. generally the scorpion was dead in a few minutes after the wound was inflicted.
of a ferocious cruel disposition, the scorpions are not only the foes of all other animals, but carry on a war of extermination among themselves, and are even said to kill and devour their own progeny, without pity, as soon as they are born; thus rendering good service to the community at large. maupertuis once inclosed a hundred scorpions—a select and delightful party—in a box. immediately a furious battle ensued—one against all, all against one—and in an hour’s time scarcely one of the combatants survived the conflict.
