Gibson William Hamilton
My Studio Neighbors
Filling the Spider's Grave
Not an hour after this episode I was treated to another of even more interest. As I took my seat upon the door-step I started into flight a big black wasp, upon whose doings I had evidently been intruding.
This wasp was much larger than the one just described, being about an inch in length. Its wings were pale brown and its body jet-black, with sundry small yellowish spots about the thorax. But its most conspicuous feature, and one which would ever fix the identity of the creature, was the long, slender, wire-like waist, occupying a quarter of the length of its entire body.
In a moment or two the wasp had returned, and stood at the mouth of the shallow pit. Eying me intently for a space, and satisfied that there was nothing to fear, she dived into the hollow and began to excavate, turning round and round as she gnawed the earth at the bottom, and shovelling it out with her spiked legs. Now and then she would back out of the burrow to reconnoitre, and her alert attitude at such times was very amusing—her antennæ drooping towards the burrow and in incessant motion; the abdomen on its long wire stem bobbing up and down at regular intervals, accompanied by a flipping motion of the wings; the short fore legs, one or both, upraised with comical effect.
Black Digger-wasp
As the tunnel was deepened a new method of excavation was employed. It has now reached a depth of an inch, only the extremity of the insect's body appearing, and the two hindermost legs clinging to surrounding earth for purchase. The deep digging is now accompanied by a continual buzzing noise, resembling that produced by a bluebottle fly held captive between one's fingers. At intervals of about ten or fifteen seconds the wasp would quickly back out of the burrow, bringing a load of sand, which it held between the back of the jaws and its thorax, sustained at the sides by the two upraised fore legs. After a moment's pause with this burden, the insect would make a sudden short darting flight of a foot or more in a quick circuit, hurling the sand a yard or more distant from the burrow. At the end of about fifteen minutes the burrow was sunk to the depth of an inch and a half, the wasp entirely disappearing, and indicated only by the continuous buzzing.
At this time, the luncheon hour having arrived, I was obliged to pause in my investigations, and in order to be able to locate the burrow in the event of its obliteration by the wasp before my return, I scratched a circle in the hard dirt, the hole being at its exact centre.
Black Digger-wasp and His Victim, Showing the Egg of the Wasp Attached
Upon my return, an hour later, I was met with a surprise. The ways of the digger-wasps of various species were familiar, but I now noted a feature of wasp-engineering which indeed seems to await its chronicler, as I find no mention of it by the wasp-historians.
At the exact centre of my circle, in place of a cavity, I now found a tiny pile of stones, supported upon a small stick and fragment of leaf, which had been first drawn across the opening.
This was evidently a mere temporary protection of the burrow, I reasoned, while the digger had departed in search of prey, and my surmise was soon proved to be correct, as I observed the wasp, with bobbing abdomen and flipping wings, zigzagging about the vicinity. Presently disappearing beneath a small plantain leaf, she quickly emerged, drawing behind her not a spider, as in the case of her smaller predecessor, but a big green caterpillar, nearly double her own length, and as large around as a slate-pencil—a peculiar, pungent, waspy-scented species of "puss-moth" larva, which is found on the elm, and with which I chanced to be familiar.
The victim being now ready for burial, the wasp sexton proceeded to open the tomb. Seizing one stone after another in her widely opened jaws, they were scattered right and left, when, with apparent ease and prompt despatch, the listless larva was drawn towards the burrow, into whose depths he soon disappeared. Then, after a short and suggestive interval, followed the emergence of the wasp, and the prompt filling in of the requisite earth to level the cavity, much as already described, after which the wasp took wing and disappeared, presumably bent upon a repetition of the performance elsewhere. But she had not simply buried this caterpillar victim, nor was the caterpillar dead, for these wasp cemeteries are, in truth, living tombs, whose apparently dead inmates are simply sleeping, narcotized by the venom of the wasp sting, and thus designed to afford fresh living food for the young wasp grub, into whose voracious care they are committed.
By inserting my knife-blade deep into the soil in the neighborhood of this burrow I readily unearthed the buried caterpillar, and disclosed the ominous egg of the wasp firmly imbedded in its body. The hungry larva which hatches from this egg soon reaches maturity upon the all-sufficient food thus stored, and before many weeks is transformed to the full-fledged, long-waisted wasp like its parent.
The disproportion in the sizes of the predatory wasps and their insect prey is indeed astonishing. The great sand-hornet selects for its most frequent victim the buzzing cicada, or harvest-fly, an insect much larger than itself, and which it carries off to its long sand tunnels by short flights from successive elevated points, such as the limbs of trees and summits of rocks, to which it repeatedly lugs its clumsy prey. In the present instance the contrast between the slight body of the wasp and the plump dimensions of the caterpillar was even more marked, and I determined to ascertain the proportionate weight of victor and victim. Constructing a tiny pair of balances with a dead grass stalk, thread, and two disks of paper, I weighed the wasp, using small square pieces of paper of equal size as my weights. I found that the wasp exactly balanced four of the pieces. Removing the wasp and substituting the caterpillar, I proceeded to add piece after piece of the paper squares until I had reached a total of twenty-eight, or seven times the number required by the wasp, before the scales balanced. Similar experiments with the tiny black wasp and its spider victim showed precisely the same proportion, and the ratio was once increased eight to one in the instance of another species of slender orange-and-black-bodied digger which I subsequently found tugging its caterpillar prey upon my door-step patch.
Protecting the Burrow while Searching for Prey
The peculiar feature of the piling of stones above the completed burrow was not a mere individual accomplishment of my wire-waisted wasp. On several occasions since I have observed the same manœuvre, which is doubtless the regular procedure with this and other species. The smaller orange-spotted wasp just alluded to indicated to me the location of her den by pausing suggestively in front of a tiny cairn. In this instance a small flat stone, considerably larger than the tunnel, had been laid over the opening, and the others piled upon it. On two occasions I have surprised this same species of wasp industriously engaged in the selection of a suitable flat foundation-stone with which to cover her burrow: her widely extended slender jaws enable her to grasp a pebble nearly a third of an inch in width.
In my opening vignette I have indicated two other door-step neighbors which bore my industrious wasps company in their arena of one square yard. To the left, surrounding a grass stem, will be seen an object which is unpleasantly familiar to most country folks—that salivary mass variously known by the libellous names of "snake-spit," "cow-spit," "cuckoo-spit," "toad-spit," and "sheep-spit," or the inelegant though expressive substitute of "gobs." The foam-bath pavilion of the "spume-bearer," with his glittering, bubbly domicile of suds, is certainly familiar to most of my readers; but comparatively few, I find, have cared to investigate the mysterious mass, or to learn the identity of the proprietor of the foamy lavatory.
The common name of "cow-spit," with the implied indignity to our "rural divinity," becomes singularly ludicrous when we observe not only the frequent generous display of the suds samples, thousands upon thousands in a single small meadow, but the further fact that each mass is so exactly landed upon the central stalk of grass or other plant—"spitted" through its centre, as it were. The true expectorator is within, laved in his own home-made suds. If we care to blow or scrape off the bubbles, we readily disclose him– a green speckled bug, about a third of an inch in length in larger specimens, with prominent black eyes, and blunt, wedge-shaped body.
The "Cow-spit" Mystery Disclosed
In the appended sketch I have indicated two views of him, back and profile, creeping upon a grass stalk. A glance at the insect tells the entomologist just where to place him, as he is plainly allied to the cicadæ, and thus belongs to the order Hemiptera, or family of "bugs," which implies, among other things, that the insect possesses a "beak for sucking." To what extent this tiny soaker is possessed of such a beak may be inferred from the amount of moisture with which he manages to inundate himself, which has all been withdrawn from the stem upon which he has fastened himself, and finally exuded from the pores of his body.
This is the spume-bearer, Aprophora, in his first or larval estate, which continues for a few weeks only. Erelong he will graduate from these ignominious surroundings, and we shall see quite another sort of creature—an agile, pretty atom, one of which I have indicated in flight, its upper wings being often brilliantly colored, and re-enforced by a pair of hind feet which emulate those of the flea in their powers of jumping, which agility has won the insect the popular name of "froghopper." They abound in the late summer meadow, and hundreds of them may be captured by a few sweeps of a butterfly-net among the grass.
My other remaining claimant for notice, shown upon the plant at the right margin of page 60, is a modest and inconspicuous individual, and might readily escape attention, save that a more intent observer might possibly wonder at the queer little tubular pinkish blossoms upon the plant—a rush—while a keen-eyed botanist would instantly challenge the right of a juncus to such a tubular blossom at all, especially at seed-time, and thus investigate. But the entomologist will probably classify this peculiar blossom at a glance, from its family resemblance to other specimens with which he is familiar. He will know, for instance, that this is a sort of peripatetic or nomadic blossom that will travel about on the plant, with which its open end will always remain in close contact. Many of the individuals are seen apparently growing upright out of the rounded seed-pod of the rush; and when the pink or speckled tube finally concludes to take up its travels, a clean round hole marks the spot of its tarrying, and an empty globular shell tells the secret of this brief attachment.
For this petal-like tube, so commonly to be seen upon the little rush of our paths, is, in truth, a tiny silken case enclosing the body of a small larva—a diminutive psychid, or sack-bearer, which I have not chanced to see described. Only the head and six prolegs of the occupant ever emerge from its case. Dragging its house along upon the plant, it attaches the open mouth of the sack close to the green seed-pod, after which the shell is gnawed through at the point of contact, and the young seeds devoured at pleasure, when a new journey is made to the next capsule, and thus until the maturity of the larva. At this time the case is about half an inch in length. It is now firmly attached to the plant. The opening is completely spun over with silk, and the case becomes a cocoon for the winter; and a few of these September cocoons are well worth gathering, if only to see the queer little moth which will emerge from them the following spring.
A QUEER LITTLE FAMILY ON THE BITTERSWEET
IN a recent half-hour's relaxation, while comfortably stretched in my hammock upon the porch of my country studio, I was surprised with a singular entertainment. I soon found myself most studiously engaged. Entwining the corner post of the piazza, and extending for some distance along the eaves, a luxuriant vine of bittersweet had made itself at home. The currant-like clusters of green fruits, hanging in pendent clusters here and there, were now nearly mature, and were taking on their golden hue, and the long, free shoots of tender growth were reaching out for conquest on right and left in all manner of graceful curves and spirals. Through an opening in this shadowy foliage came a glimpse of the hill-side slope across the valley upon whose verge my studio is perched, and as my eye penetrated this pretty vista it was intercepted by what appeared to be a shadowed portion of a rose branch crossing the opening and mingling with the bittersweet stems. In my idle mood I had for some moments so accepted it without a thought, and would doubtless have left the spot with this impression had I not chanced to notice that this stem, so beset with conspicuous thorns, was not consistent in its foliage. My suspicions aroused, I suddenly realized that my thorny stem was in truth merely a bittersweet branch in masquerade, and that I had been "fooled" by a sly midget who had been an old-time acquaintance of my boyhood, but whom I had long neglected.
Every one knows the climbing-bittersweet, or "waxwork" (Celastrus scandens), with its bright berries hanging in clusters in the autumn copses, each yellow berry having now burst open in thin sections and exposed the scarlet-coated seeds. Almost any good-sized vine, if examined early in the months of July and August, will show us the thorns, and more sparingly until October, and queer thorns they are, indeed! Here an isolated one, there two or three together, or perhaps a dozen in a quaint family circle around the stem, their curved points all, no matter how far separated, inclined in the same direction, as thorns properly should be. Let us gently invade the little colony with our finger-tip. Touch one never so gently and it instantly disappears. Was ever thorn so deciduous? And now observe its fellows. Here one slowly glides up the stem; another in the opposite direction; another sideways. In a moment more the whole family have entirely disappeared, as if by hocus-pocus, until we discover, by a change of our point of view, that they have all congregated on the opposite side of the stem, with an agility which would have done credit to the proverbial gray squirrel.
This animated thorn is about a quarter of an inch long, and dark brown in color, with two yellowish spots on the edge of its back.
Nor is this all the witchery of this bittersweet thorn. It is well worth our further careful study. Seen collectively, the thorny rose branch is instantly suggested, but occasionally, when we observe a single isolated specimen, especially in the month of July, he will certainly masquerade in an entirely new guise. Look! quick. Turn your magnifier hither on this green shoot. No thorn this. Is it not rather a whole covey of quail, mother and young creeping along the vine? Who would ever have thought of a thorn! Turning now to our original group, how perfectly do they take the hint, for are they not a family of tiny birds with long necks and swelling breasts and drooping tails, verily like an autumn brood of "Bob Whites"?
A Bittersweet Covey
But the little harlequin is as wary a bird as he was a thorn! No sooner do we touch his head with our finger than with an audible "click" he is off on a most agile jump, which he extends with buzzing wings, and is even now perhaps aping a thorn among a little group of his fellows somewhere among the larger bittersweet branches.
It is only as we capture one of the little protean acrobats between our finger-tips and examine him with a magnifier that we can really make "head or tail" of his queer anatomy. Even thus enlarged it is difficult to get entirely rid of the idea of a bird. I have shown a group of the insects in various attitudes, the position of the eyes alone serving as a starting-point for our comprehension of his singular make-up. The tall neck-like or thorn-like prominence is then seen to be a mere elongated helmet, which is prolonged into a steep angle behind, so as to cover the back of the creature like a peaked roof, a feature from which the scientific name of this particular group of insects is derived, Membracis, meaning sharp-edged, the sides of the slope being covered by the close-fitting wings, which, though apparently compact with the body of the insect, are nevertheless always available for instant and most agile flight. We now discover two pairs of stout legs just beneath the edge of the wings, a third more slender pair being concealed behind, ready for immediate use in association with these buzzing wings when the whim of the midget prompts it to leap.
Flushing the Game
This insect is the tree-hopper, and is but one of many equally curious and mimetic species to be found among the smaller branches of various trees and shrubs.
Our largest membracis is to be seen—with difficulty—on the terminal twigs of the locust-tree, its outlines so exactly imitating the thorny growths of the branch as to escape detection even by the closest scrutiny. Another remarkable species is a protégé of the oak, so closely simulating the warty bark of the smaller branches upon which it is found that our eyes may rest upon it repeatedly without recognizing it. The life history of these singular insects is quite similar, and is soon told. The membracis belongs to the tribe of "Bugs," Hemiptera, which implies that it possesses a beak instead of jaws, by which it sucks the sap of plants, precisely like the aphis, or plant-louse. This tiny beak we can readily distinguish bent beneath the body of our bittersweet hopper. Inserting it deep into the succulent bark, the parasite remains for hours as motionless as the thorn it imitates, the lower outline of its body hugging close against the bark. The curious suggestion of the thorn is produced not only by the outline, but by the curious fact that the hopper never sits across the twig, but always in the direction of its length; and, what is more, the projecting point of the thorax is always directed towards the end of the branch, or direction of growth. It is no easy thing even for the casual botanist to determine this nice point in a given segment of a bittersweet branch placed in his hand, the position of the chance leaf or leaf scar being his only guide. But the Membracis binotata rarely—indeed never, so far as I have examined—makes a mistake. Thus the wandering spray of bittersweet, recurve and twist upon itself as it may, will always disclose the little hopper or colony of them headed for its tip.
Specimen Twig
But I have omitted to mention one singular feature which is the usual accompaniment of my group of hoppers, and is, indeed, the most conspicuous sign of their presence on any given shrub. In the cut below I have indicated a short section of a bittersweet branch as it commonly appears, the twig apparently beset with tiny tufts of cotton, occasionally so numerous as to present a continuous white mass, usually on the lower side of the branch, where its direction is horizontal. They are thus easily seen from below, and a closer examination will always reveal one or more of the black animated thorns in their immediate vicinity, suggesting the responsible source. These tufts are pure white, a little over an eighth of an inch in length, and semicircular in vertical outline. The natural presumption is the idea of maternity, the mother hopper guarding her bundles of white eggs, or her infant hoppers, perhaps, snugly tucked up in their downy swaddling-clothes. But a closer examination completely dispels this illusion. Instead of the supposed fluffy cotton, we now discover the white substance to be of firm though somewhat sticky consistency, its surface, moreover, beautifully ridged from base to summit in parallel rounded flutings, which meet and interfold like a braid along the summit. If with a sharp knife we now cut downward through and across the mass, we find our tuft to be a mere frothy shell containing two hollow compartments, with a thin central partition extending through the whole length of the cavity. But there is no sign of an egg or other life to be disclosed anywhere, either in its substance or its concealment. What, then, is the office of this tiny fragile house of congealed foam, with its snowy aerated structure, its double arched chambers, its corrugated walls and ceilings, and missing tenant or host? Such was the riddle which it propounded to me, and guided by some previous knowledge of the habits of allied insects, I was soon enabled to witness a solution of at least a part of its mystery.
This little thorn-like tree-hopper and all of its queer harlequin tribe are near relatives to the buzzing cicada, or harvest-fly, whose whizzing din in the dog-days has won it the popular misnomer of "locust."
To the average listener this insect is a mere "wandering voice and a mystery," and its singular form, wide prominent eyes, glassy wings, and double drums are always a surprise to the tyro who first identifies the grotesque as his well-known "locust." Its musical accomplishments during this brief period of its life are known to all, but few have cared to interest themselves in the early history of the singer, ere it perfected its musical resources "for the delight of man." But the naturalist, and especially the arboriculturist and fruit-grower, know to their cost of other tricks of the cicada, or rather of Mrs. Cicada, immortalized by Zenarchus the Rhodian as his "noiseless wife"—
"Happy the cicadas' lives,
Since they all have noiseless wives."
I have alluded to the egg of the cicada "inserted in the bark of a twig." This act is accomplished by a knife-like ovipositor, which literally gouges a deep gash into the tender wood of various twigs, a number of the eggs being implanted in its depths, often causing the death of the branch. Shortly after hatching, the young cicadas leap for the ground, and burrowing beneath the surface, remain for a period varying from three to seventeen years, according to the species, to complete their transformations. Now the habits of my little tree-hopper are somewhat modelled after its big cousin. Knowing that the little insect was provided with a keen-edged ovipositor, and was in the habit of thrusting its tiny eggs beneath the bark, and realizing, too, that these strange tufts were of course in some way connected with the maternal instinct, I was led to investigate. Selecting a branch where the tufts and hoppers seemed most prolific, I brought my magnifying-glass to bear upon them at a respectful distance. Was ever actual thorn more motionless or non-committal than most of these?—their under surfaces hugging close against the bark, their telltale feet closely withdrawn, and all their pointed helmets inclined in the same parallel direction. One after another of the sly little family was examined without a revelation. Not until I had reached the upper limit of the group did I get any encouragement. Here I discovered one of the midgets in a new position, its pointed helmet inclined farther downward, and its other extremity correspondingly raised, so that I could see beneath its body. I now observed what at first appeared to be the hind leg of the farther side of the body protruding beneath, but in another moment noted my error, and saw that its sharp point had penetrated the bark, into which it soon sank quite deeply, and I realized that the ovipositor was now conducting its tiny eggs into the cambium layer of the bark. Without waiting for this particular individual to finish her labors, which might be extended for hours for aught I knew, I turned my glass upon its nearest neighbor, and a most accommodating specimen she proved, disclosing all the mysteries of the little froth house, its strange material, and unique method of construction. What I saw reminded me irresistibly of the technique of the cake-frosting art of the fancy baker, with its flowing tube of white condiment, and its following tracery of questionable design in high relief. This accommodating specimen had apparently just completed her egg-laying, or had perhaps just filled one nest; and while her attitude was precisely similar to that of her neighbor, I noticed a tiny ball of glistening froth at the tip of the ovipositor. This was attached to the bark by a touch, and from this starting-point the construction of the glistening house was continued, the apex of the ovipositor pouring out its endless puffy roll of aerated cement, which seemed to set as soon as laid.
And what a convenient implement this for a froth-house builder who is compelled to work behind her back—mortar-feeder, trowel, darby, compass, and level all in one! Beginning with the first touch of the cement, the flowing point describes a very small half-circle to the right, again meeting the bark. It is now carried inward and upward, describing a very close circle with scarcely any space intervening, a similar circle being repeated on the left side. A new tier is then begun in the same manner, only this time a little larger in the sweep, and leaving a perceptible opening at the right as the central wall is carried upward with slightly decreased material. Returning down the central wall again, the white coil is carried to the left along the bark, and up again on the other outer edge, until it once more meets its fellow at the ridge-pole, where the two coils appear to interlock as in a braid. And thus the little builder continues, enlarging the cavity with each circuit, until the full height is reached, and then decreasing proportionately until the glistening braided dome is tapered off again against the bark.
Building Froth-tent
Now what is the object of this frothy pavilion? The life history of the insect, in contrast to that of the cicada, will perhaps throw a little light on that question. In the cicada, as I have shown, the eggs are inserted in the bark, but the young, hatching about six weeks later, immediately forsake the parent tree and enter the ground. But the young of our bittersweet membracis are not thus fickle, the entire life of the insect being spent on the plant. Moreover, its eggs are laid in late summer, and do not hatch until the following spring. What, then, is this canopy of the tree-hopper but the provision of a thoughtful mother, a pavilion about her offspring as a shelter through the winter storms? In early July the tiny hoppers emerge from their egg-cases, and presumably creep out from their luminous domicile, and later on in the season these broods of varying numbers and all sizes are to be seen among the young stems of the plant, their beaks inserted, their pointed heads invariably in the same direction—towards the top of the branch. Even though in flight one of the midgets is seen to alight in violence to the rule, he instantly recognizes his mistake, and quickly glides round to the orthodox position.
This curious insect is chiefly confined to the bittersweet, though he is occasionally found in the company of a much bigger cousin of his on the branches of the locust, where these same telltale corrugated frothy pavilions are often seen to clothe the young twigs in their white tufts, the similar product of the larger species, which thus also presumably spends its entire life upon the locust-tree.
