Part 5

She is building a little tube out of sand which is so delicate that the slightest touch from one of our own clumsy fingers will knock it down like a card-house, but it is strong enough for her to crawl inside; and she has to crawl inside very often, as you will see. I expect you will all want to know how she builds it, and what it is for. I will tell you how she builds it to begin with. You must know first that she has a pair of jaws which work quite differently from ours. Instead of moving up and down, they move across each other from side to side just like a pair of scissors.

The first thing that Spinipes does is to work this little pair of scissors in the sand so as to make a little hole. I am showing you on page 148 a picture of her when she is just starting to dig. Every little pellet of sand she digs out she puts carefully round the outside of the hole, and presently she glues them all together. She carries the glue somewhere inside her, and brings it out when she wants it, Then she digs a little deeper and glues another layer of sand pellets on the top of the first one, and in a very short time she has dug a hole about two inches deep, and built a little tube round the top of it, which is made of the little sand-pellets she has brought out of the hole. Sometimes the tube stands straight up, but more often it bends about half-way and curves downwards. When she has finished it off, and is sure that the hole is deep enough, and the tube is long enough, she goes right down to the bottom and lays an egg, and she hangs the egg by a tiny thread (which she also makes herself, but I don't know how she does it) to the side of the hole a little above the bottom. You will be able to see this in the picture, but you must remember that in this and in some of the other pictures the sand has been cut away so that you can see exactly how the hole goes. Then, if it is a bright, sunny day, as it usually is when she begins digging, she flies away, and in about half an hour's time comes back carrying something clasped tight against her body. What do you think that is? It is a small green caterpillar. She stops a moment at the entrance of the tube, pushes the caterpillar down in front of her, and disappears after it. In a few seconds she is out again and off, and in another quarter of an hour or so she is back again with another caterpillar and so on, without ever tiring, through six or seven hours of a hot June or July day.

I expect you will have guessed what the caterpillars are for. They are food for the wasp grub when it hatches out of the egg. Generally each hole has between twenty and thirty little caterpillars in it, and sometimes, when caterpillars are scarce, the Mother Wasp has to work hard for three or four days. If you dig into a hole yourself and look at the store of little caterpillars, you will see there is something the matter with them. They seem to be alive and yet they don't seem to be able to crawl. Wise men say that the wasp stings them just enough to make them drowsy so that they can't crawl out of the hole, and can't hurt the wasp grub by jostling up against it. It wouldn't do to kill them, because then they would go bad in the hole before the grub had time to eat them. This sounds rather cruel, but I don't think it is really, because it is quite certain that the caterpillars cannot feel as we should perhaps feel, and we may be quite sure that in the wonderful Nature World everything is arranged for the best, so that only the right number of wasp-grubs may be properly fed and grow up to do what it is their duty to do, and only the right number of small green caterpillars may grow up also.

You will wonder, I expect, why the Mother Wasp troubles to make the little tube above the hole. I think I can tell you one reason and you must remember this, because it was just by chance that I found it out. One hot morning in June I watched Mother Spinipes bringing seven caterpillars to her hole. Then a heavy thunderstorm came on, and the rain came down in buckets, and I had to run away for shelter. Late in the evening when it had cleared up a little, I thought I would like to see what had happened to the tube I had been watching, and I went back to the place and found that the rain had knocked it all to pieces. But I saw something much more interesting than this. The tube had been on the face of a sand-cliff, and in a crack close by there was an ants' nest. I found that the ants were running down the wasp's hole and bringing out the caterpillars as fast as they could (I saw them take six away), and taking them along the face of the cliff into their own stronghold. Now the tube that stands out from the sand somehow frightens the ants (I never saw an ant climb out along the tube and down inside it), and so I think that one of the reasons for the tube must be that it keeps away ants and creatures of that kind who crawl about on the face of the sand cliff and like eating caterpillars.

It was a long time before I found out what kind of creature the caterpillars stored by Spinipes would have turned into if they had not been caught. I thought that it would have been a small moth, but I was quite wrong. At different times I took several caterpillars away from the tubes, and tried to bring them up, but it was of no use, for they all died because they could not eat. One day, however, I happened to be sweeping with a butterfly-net in a field of lucerne--it is great fun sweeping, and you should try it, for you never know what you may get next--and I swept up what I knew at once was the self-same little green caterpillar that Spinipes stocked her larder with. She _always_ brought the same kind. Well, I got a good many of them by sweeping in the lucerne, and brought them up carefully, and, in due time, they spun little open-work cocoons on the lucerne leaves which I fed them with, and at last turned into small, brown, long-nosed beetles. I need not trouble you with the Latin names of these beetles, but I may tell you that they are a kind of weevil which is very common and very destructive to clover and plants of that kind. So, if we consider that every Mother Spinipes lays eight or nine eggs, and stocks eight or nine burrows each with about thirty destructive little caterpillars, we must allow that she is a very useful little wasp.

But I am not sure that she is more useful to man than the other little wasp I have to tell of, the Crabro. I found out her usefulness quite by chance, and I expect you will like to hear how. To begin with, I must tell you that all the "Digger" Wasps, as some people call them, Spinipes and the Crabros and several other kinds, store their burrows with insect food for their grubs to feed on.

But each one has her own particular idea as to what is the _best_ food. One will use nothing but little spiders, another nothing but little flies, another, like Spinipes, nothing but little beetle grubs. And the queer part is that they seldom seem to make any mistake as to the kind of food they want. It will be _one_ kind of spider, and _one_ kind of fly, and _one_ kind of beetle-grub. If there are ever more than one kind, they are always very near relations, and, I suppose, taste very much alike.

Now Crabro's store consists of really _large_ flies, blue-bottles, and green-bottles--I expect most of you know the beautiful shiny green-bottle fly whose proper name is Caesar--and how little Crabro manages to overcome and carry off large bottle-flies who are several times her own size and several times her own weight, I cannot tell. But I have found out for certain that she does so, and the pictures will show you how I found out.

Last autumn a dangerous bough had to be taken down from the top of a high elm-tree in my garden. It was perhaps sixty feet above the ground and it came down with a crash and broke up into little pieces. I picked up one of these tubes and galleries, which I knew were insects' work. But there was something much more exciting than this. A number of the galleries had blind ends to them, and at the bottom of these were masses of dead blue-bottles, tightly packed, which rested on small pillows of sawdust, and had long plugs of sawdust above them.

I opened one of the long sawdust plugs and found, as I half expected to find, that at the end of it next to the blue-bottles, was a small brown papery cocoon, and that inside the cocoon was a wasp grub. I need hardly tell you that I collected a lot of the wood, and kept it carefully through the winter, and tried to make the little grubs as much at home as if they had stayed up in their tree. To do this I had to keep the wood in moist and rather dark surroundings. Then when the spring came round I sometimes put the wood in the sunshine, when it was not too hot, and in the first week in June I was rewarded for my trouble, for the little wasps hatched out in dozens, and so I was able to find out what they were.

Look up to the top of the trees some warm summer day, and think of the blue-bottle hunt which may be going on above us, and of the wonderful little hunter, Crabro.

SPINIPES THE SAND-WASP (MIDSUMMER DAY)

AUTHOR'S NOTE

This insect-tale is based on observations of fact extending over several summers. It may interest some of my readers to know the scientific names of the chief characters mentioned. I do not think that any of them have popular names. The heroine is the solitary Sand-Wasp _Odynerus Spinipes_, a blacker and somewhat smaller insect than the familiar yellow Wasps of Town and Garden. The Red King and the Black Queen are the male and female of a solitary Bumble Bee, _Anthophora Pilipes_. The Mistress of the Robes is a "Cuckoo" Bee, _Melecta armata_, which attends on Anthophora, and lays its eggs in the cells made by Anthophora for her own eggs. The grubs of both feed on the honey and pollen which _Anthophora_ alone has the trouble of procuring. _O. Spinipes_ has several cuckoos, the most officious being the jewel flies, _Chrysis ignita_ and _Chrysis bidentata_, whose grubs, I fancy, eat the grub of Spinipes, as well as the food stored up for it. The Ophion is a common Ichneumon fly, and the beetle-grubs belong to a very common and destructive weevil, _Hypera variabilis_.

The Sand Cliff splits the old gravel-pit in two, and, jutting southward, fronts the mid-day sun. The cuttings driven east and west of it have long been clothed with furze and briar and nettle. Rank grass conceals the cart-track round its base, and, on its summit, a thin, root-bound soil gives foothold to a straggling hedge of privet.

Man, needing gravel only, scorned the sand; and, as he turned his back on it, came Nature, gently mothering; and brought it warmth, and light, and life.

First the wild Bees, Red Kings, Black Queens, fringe-footed, shaggy-coated. These made a chambered palace of the cliff, and peopled it within a summer. With them came Lords-in-Waiting and their Ladies, in liveries of black velvet, ermine-faced; and, after these, a fluttering gauze-winged host--jewel-flies ablaze with green and blue and crimson, trim slender-waisted digger-wasps, long-streamered swart ichneumons. And, last of all, came Spinipes herself.

Straight from the blue she dropped on May's last morning, swerved through the hum and racket of the Bees, poised with her smoke-grey wings a-whir, and lighted softly on the centre ledge, her ebony body mirroring the sun, her five gold girdles blazing.

Down dropped a Red King at her side. He stared at her right royally, and kept right royal silence, yet there was kindness in his yellow face, and kindness in the purr of his departure.

Down dropped a Black Queen in his place, and danced and hummed about her, and measured her slim-waistedness, and buzzed her disapproval.--"What is it?" asked she snappishly. "Why does it come in this get-up? Where has it left its furs?"

"It never had furs," said a voice behind her. It was her Mistress of the Robes.

"I know the family, Ma'am. Queer clothes, of course. But artists, Ma'am, artists to the toe-tips."

"Artists in what?" said the Black Queen.

"In Sand, Ma'am, in Sand. See, she's starting now."

"That's hive-bee's work," said the Black Queen contemptuously.

"The art comes at the finish, Ma'am----"

"Well, call me when it comes," said the Black Queen, "and keep her off the nurseries, and clean that eleventh cell of mine, and wait till I come back. She soared up skywards, fussily, cleared the cliff's head, circled three times about, and set a straight course south.

"Good riddance!" said the Mistress of the Robes.

"They're like that everywhere," said Spinipes. "What are her nurseries to me? Black Queens and black sand go together. Now this is red sand. I feel the grip and bind of it."

She was quite right. The ledge was rain-washed silt. Sunshine had bleached the outer crust of it, but, under this, its substance was brick-red--fine ground stuff too, damp, clingy, easily tunnelled, and easily smarmed into a hold-fast mortar.

"In that case," said the Mistress of the Robes, "I may as well be going."

Slowly she floated off the ledge, yet kept her face towards it. Slowly she tacked from side to side, in dipping, widening sweeps. Slowly she passed the cliff's east edge, and disappeared.

_Then_ Spinipes commenced to dig in earnest.

Her scissor-jaws worked viciously, carved four-square pellets from the sun-baked crust, gripped them and flung them backwards. As she engaged the softer soil, she added feverish foot-work, and scraped, and rasped, and scrabbled it, and kicked it back in dust-clouds. Her head was quickly buried, next her waist, and, presently, she disappeared completely.

But not for long.

She backed up to the surface, dragging a sand-load underneath her body. She shook this clear, and, without resting, dived afresh. Ten loads in all she raised, and each one meant a longer spell below. For she had more to do than dig. From end to end her shaft must needs be glazed--and this meant patient mouth-work, deft steadying touches as the mortar set, and skill to keep her tube's round symmetry, and guide it in a gentle curve to end in quiet darkness. Three inches down she sank, and, at the bottom, drove a slant, and hollowed out a store-room.

With this the first stage ended. She left her shaft, and, poising in mid-air, made survey of the ledge. To right she swerved, to left again, outwards and back, upwards and down, until its bearings east and west, from sky above, and earth below, were rooted in her memory.

So far, so good--her morning's work was done, the picture of it fixed into her mind. Upwards she soared until the receding cliff shrunk to a splotch of brown. Once more she took her bearings and was satisfied, set her course east, and, with a dropping arrow's flight, came to the hill-top coppice. She landed on the bramble hedge which skirts its western clearing.

"Good hunting, sister!" said the Ophion Fly. She sat on a high briar-leaf, her rainbow wings uplifted.

"It's hardly time for that," said Spinipes. "To-morrow, p'raps. To-day I feed myself."

"There's lucerne on the slope," the Ophion said, "and something underneath you."

There was a snap and flicker in the grass, and presently appeared a pygmy beetle, long-snouted, dusty-coated, trailing its slow legs wearily.

"D'you _see_ it?" said the Ophion Fly.

"I see it, but what of it?"

"It means good hunting, sister. Green grubs, black-headed, fatted. Too small for me, but just the size for you. You'll find them in the lucerne."

"Thank you," said Spinipes, but she was half across the field, a dancing, filmy wisp of pink, wind-borne.

A meal, and then to work, thought Spinipes. It must be done by sunset. It must. It must.

From spray to spray she flitted. Flower after flower she robbed of its pale nectar. Bud after bud she nibbled. At last she found the food she sought, and, with her strength renewed, took flight. Upwards she soared; three times she circled round; then in a straight, unbroken course, whizzed to her shaft. Her pace was scarcely slackened as she entered. Her wings closed lengthways on her back, and, in a moment, she was at the bottom.

Something was there before her.

Something six legged, which kicked and squirmed and writhed. Something which coiled to a hard, slippery ball, and rolled away from capture.

There was no space for it to pass, and yet there seemed no holding it. At last she pinned it with her feet, and, backing, dragged it upwards to the light. It was a radiant jewel fly, a squat, short-waisted, dumpy thing made glorious by its colour. Gems sparkled on it head to tail, sapphire and ruby, emerald and topaz, and, as it struggled, fire of gold blazed and died down upon its jerking body. Instinctively she shook and worried it. Instinctively she flung it down the slope. Head over tail, tight-clenched, it spun, nor opened till it reached the grass below. Here it snapped out to shape again, took instant wing, and, with a glancing flight, regained the ledge.

"An excellent shaft, Madam; quite excellent. No doubt you made it for a special purpose. Now I----"

"Listen to me," said Spinipes, "and mark my every word. If you come near that shaft again--if you so much as touch it with your feet, I'll sting your prying life out."

She charged at it full swing and chased it off the ledge.

"An area sneak!" she muttered, as she dropt underground once more--"and over-dressed at that."

Below the walls showed signs of the encounter--it took ten minutes to repair their glazing. When this was done, she crept back to the entrance. It was high noon. A shimmery haze rose from the heated sand. The hum of work died fitfully away, as, one by one, the homing bees sought shade. The digger-wasps dived deep into their holes; the hunting spiders hid themselves. These were the last to cease from work; the last to cease from play was the rose-chafer.

Him the fierce blaze of heat impelled to bursts of clumsy flight. Across the pit and back again, and up and down the surface of the cliff, he whirred and swung at random. Soon even he grew listless, and crept within the shelter of the privet.

The change came with a catspaw breeze, which rippled from the valley, and, in its quiet passing, fanned the cliff.

It brought back life and energy.

Out flew the bees, a jostling, buzzing throng of them, see-sawing wildly up and down, swinging, reversing, wheeling. At length they towered and broke to work. Out crept the hunting spiders, zebra-coated; the fluttering, dancing, digger-wasps; the lightning-footed ants. Out, last of all, came Spinipes herself.

Her first care was her toilet. She combed her long antennæ out and nibbled at each foot. A circling flight to stretch her wings ended where it had started; and, in a moment, she had plunged below. Two minutes she stayed underground, then came up slowly backwards. Between her jaws was a clean-cut sand pellet. She placed it on the rim of the shaft opening, and, with deft touches from her lips, cemented it in station. She danced about it joyously, with fluttery wings, with airy, buoyant feet, moistened it here, kneaded it there. Once more she dived and dragged a second pellet up, and fixed this too upon the rim. So diving, digging, fixing, shaping, she raised a low ring-parapet.

Hour after hour she toiled, tier after tier she added, gluing each pellet firmly to the last, yet leaving open space between each junction. So rose a filagree tube of sand, so fragile that a touch would crumble it; so strong that it would bear four times her weight. Before a shadow reached the cliff, it was a half-inch high. But shadows meant an end to the day's work, and Spinipes crept down below and slept.

The morning sun had shone four hours before she stirred. She peered out round-eyed from her tower, and, twisting on the rim of it, hung for a while head-downwards. A flash of green and crimson light, and something settled under her. It was the Jewel Fly again.

"Fine progress, Madam, and a first-rate tower. I never saw a better."

No word said Spinipes, but straightway launched, and flew at her.

"Out, cuckoo-sneak!" she screamed. "Out! or I sting!"

The Jewel Fly dodged like a gnat, and vanished round the corner.

She certainly meant mischief.

The lowest chamber of the shaft now held a precious thing--a spindle-shaped gold egg, slung to the side-wall by a silken thread. Back darted Spinipes to look at it; and test the fine-spun sling again; and fuss with it; and feel that it was hers.

Then up to her look-out once more. This time she dropped down to the sand and sunned herself contentedly.

The Bees had long been working. Forward and back they passed unceasingly, now and again one towered, now and again one settled; but never did their labour-song, a droning, buzzing, humming chanty, weaken or gather strength. The Jewel Fly had vanished altogether, yet Spinipes still seemed to fear her coming. A full half hour she stayed on guard, and spent the time in adding to her tower, and rounding off its entrance, which, of its own weight, took a gentle down-curve. Then, after one last gaze upon her egg, she flew afield.

"Good hunting, sister!" said the Ophion Fly. She sat on the same leaf as yesterday.

"I want them now," said Spinipes.

"The're thousands of them, thousands," said the fly, "and most of them quite fat."