€ OeteTOO0 TOEO O MUMIA IOHM/18WN of” vl hme, rae ANT COMMUNITIES n . b rien t is 4 oe a j = f - ? : j ‘ ‘ ; r s - J ¥ a + = 7 ea : J : r , 1 fee Ne e if 7 Ce. =. Bans «3 7 hid ice. HONEY-BEARING ANTS Fig. 1. Side view of honey-bearer x2 (honey-ant, Garden of the Gods). Fig. 2. Dorsal view of honey-bearer of Camponotus inflatus. (After Lord Avebury.) Fig. 3. Dorsal view of Fig. 1. Figs. 4 and 7. Views of males of Hortideorwm. Figs. 5 and 10. Winged female, or virgin queen, of Hortideorwm. Figs. 6 and 11. Node, or scale, of the petiole of queen of honey- ant. Fig. 8. Worker-minor of M. Hortideorum x 4. The workers major and minim, or dwarf, are similar in form. Fig. 9. To show the striz (str.), supposed stridulating organs of Myrmica ruginodis. Fig. 10. Winged female, or virgin queen, of Myrmica ruginodis. Fig. 11.,Node, or scale, of the petiole of No. 10. For detailed description, see page 109 and following pages. | Ler aly is ee! ie a sino ine im vcomrpse tin had ANT COMMUNITIES AND HOW THEY ARE GOVERNED A STUDY IN NATURAL CIVICS BY HENRY CHRISTOPHER MCCOOK AUTHOR OF “* NATURE’S CRAFTSMEN ”’ ‘““TENANTS OF AN OLD FARM”? EG. EG HARPER & BROTHERS FUSS HeERS NEW YORK, ANDELON DON 1QO9Q Copyright, 1909, by HARPER & BROTHERS. All rights reserved. Published October, rgo9. TO MY BROTHER GENERAL ANSON GEORGE MCCOOK COMPANION, COMRADE, FRIEND, ALWAYS LOVING AND WELL-BELOVED. IN EVERY OFFICIAL TRUST BRAVE; PATRIOTIC, .-COMPETENT, AND INCORRUPTIBLE. IN EVERY RELATION OF. LIFE. JUST, HONGRABLE LOYAL, AND KIND A’ FUEL-ORBEDYMAN 2 ‘ or 7 ; Tee J “sl : > rey nei & aa abv fen Un e's 1d ove aa fae ‘Gs, DA mebee HE ue . La Li _— hes +. = i? 7 : a - - yale = Le © 7 a) a ie 4 CHAP, CONTENTS PAGE lcarTOIDy (Gilg cal oy OMe Pee een ey eRe ae Oe Dates Pere 2) Oh eye TN Vv FRATERNAL CONFEDERACIES AND COMMUNAL RuiGHT- EOUSNESS AMONG SociAL ANTS ...... . 1 NeEsTING ARCHITECTURE—HouUSING THE COMMUNE . 17 ENGINEERING METHODS IN ANT STRUCTURES .. . 49 SUPPLYING THE COMMUNAL RATIONS ..... . 77 FEEDING THE COMMUNE ere ee. eee ee ee I THE LANGUAGE OF ANTS AND OTHER INSECTS ieee! HowcAnTs COMMUNICATE >, Vea. ee ee Se FEMALE GOVERNMENT IN ANT COMMUNITIES .. . 155 THE PRORLEM OF COMMUNAL DEPENDENTS . .. . 171 WARRIOR ANTS, AND THEIR EQUIPMENT FOR WaR . 190 ow AnTs CARRY ON WAR” <°..:.¢..00 4 ©.0h eo eee ALIEN ASSOCIATES AND AFFINITIES IN ANT CoMMUNES 224 . APpHis HERDS AND AnT ASSOCIATES ..... . 243 THE .FoUNDING OF SLAVE-Makinc ANT ComMMUNES . 261 PROBLEMS OF SANITATION AND PERSONAL BENEVOLENCE 279 AANOTEOIN REVIEW “20:3 « Sica) a eee ee ee TABLE OF AUTHORS AND REFERENCES Nm ay ote 9 5 RT) ce lel MG Pit we fA TrONS HONEY-BEARING ANTS . . .. . . . . + «+ Frontispiece A GROUP OF MOUND-MAKING ANTS’ NESTS WATCHMEN AROUND THE GATE OF A HONEY-ANTS’ NEST GROUP OF TWO MOUNDS OF F. EXSECTOIDES AT ALGONAC, ST. CLAIR RIVER, MICHIGAN . SINGLE MOUND OF F. EXSECTOIDES, BRUSH MOUNTAINS, PENN- SME WANIEAMS ote cM Se) ako co ORIGINAL CELL OF CARPENTER ANT QUEEN, AFTE WHEELER EXTERIOR ARCHITECTURE OF HONEY-ANTS OF THE GARDEN OF THE GODS. INTERIOR OF A STORIED COMMUNE OF THE OCCIDENT ANT OVER EIGHT FEET DEEP . A CONNECTED SERIES OF STORE-ROOMS, OR GRANARIES AND CHAMBERS, OF THE OCCIDENT ANT .. . PEBBLE-ROOFED COMMUNE OF THE OCCIDENT ANT LITTLE HEAPS OF EARTH-PELLETS THROWN UP AROUND THE GATES OF PHEIDOLE PENNSYLVANICUS, THE SIMPLEST REE VOR TANT-MOUND. = (oso :30- 2) Gi ai J. Goa eae CREMASTOGASTER LINEOLATA. CARTON COCCID-TENT OF CREMASTOGASTER LINEOLATA-PILOSA EEC) nd ae a eee EM Se ee PASTEBOARD NEST OF DOLICHODERUS BITUBERCULATUS MAYR, UR ONEEEARIICORS 0! . Winco Ged. Sal van) NEST OF CAMPONOTUS RUFIPES ON A TREE. .... . NEST OF PSEUDOMYRMA BELTI ON MEXICAN ACACIA THORNS PSEUDOMYRMA BELTI (EMERY) MAGNIFIED . ..... . PEIN ARY ENGINEERING >. < fie agetiecd ae eee eu ele SECTIONAL VIEW OF ANT-MOUNDS . ... . « «6 & 7s xi PAGE ANT COMMUNITIES AM NGINMMERING: sy 27.) Jc bab a ee a, Ore See ee MOUND-MAKING ANTS COVERING A DOUBLE GALLERY . . ANTS DIGGING OUT GALLERIES bbl dy Re agate hee AN AGRICULTURAL ANT’S FOOT, ENLARGED 180 DIAMETERS: THE TOOL USED, WITH THE JAWS, IN DIGGING. .. . THE CIRCULAR DISK AND ROADS THAT SURROUND THE ONE CENTRAL GATE OF THE AGRICULTURAL ANT OF TEXAS . AGRICULTURAL ANTS CUTTING GRAIN TO CLEAR ROADS AND DISK. Fo oe Pi narasy fe ys ae et nt ee ag, We AONPE ORE YING. A, PELLR TOE SOlis.. = ai!) 2. wel ene A SPECIMEN OF GRAIN-STALK ON AN ANT CLEARING ... . AGRICULTURAL ANT CARRYING GRAIN-STALKS . .... . OCCIDENT ANTS: SINGLE AND DOUBLE GATES OPEN... . OECIDENT- ANTS (CLOSING: GATES = els hie ce A CLOSED GATE OF CUTTING ANTS OF TEXAS . . .. . - CUTTING ANTS) A, GATH WIDE, OPEN) 2 2. cals) Cee eee CUTTING ANTS: A GATE IN PROCESS OF CLOSING. ... . GUSTATORY ORGANS OF THE HONEY-ANT = °° ,) cil 2 4 AGRICULTURAL ANT FEEDING FROM A HICKORY-NUT KERNEL MOUND NEST OF TEXAS CUTTING ANT UNDER A LIVE-OAK TREE PABTDY. -DEROLMATED (> fas o4, «. f) 2 Ue ieee THE HEAD OF A THXAS CUTTING ANT. i, | 2.02 "soon 5 A PROCESSION OF TEXAS ANTS CARRYING LEAVES TO THEIR (CAVES Tc 25-551 t wet CUTTING ANTS: i. sae SECTIONAL VIEW OF A CUTTING ANTS’ NEST A PIECE OF LEAF-PULP WHICH FORMS THE MUSHROOM GARDEN SPRIG OF DWARF-OAK (QUERCUS UNDULATOR), WITH GALLS EXUDING DROPS OF SWEET SAP. (4. (2) een THE DIGESTIVE TRACT OF A HONEY-ANT. . . | = 4. HONEY-BEARERS OR ROTUNDS ABDOMENS OF HONEY-ANTS SECTIONAL VIEW OF THE STOREROOMS OF THE OCCIDENT ANT OCCIDENT ANT HARVESTING SEEDS OF WILD SUNFLOWER POSTURES OF THE FLORIDA HARVESTER IN CUTTING SEEDS FROM THE STEM. «. $-.<)320 aR 2) See SECTION PENNSYLVANIA HARVESTING ANT ..... . xii 109 110 111 112 115 116 117 118 ILLUSTRATIONS MIMETIC LANGUAGE IN ANTS. ANTS IN ATTITUDE OF COURAGE, ANGER, AND ALARM .. Pa EEG TIAING UINCB iy rs oy gs) ae on 09h, oe) DEATH’S-HEAD MOTH WHICH MIMICS THE PIPING OF A QUEEN BEE STRIDULATING ORGANS OF LOCUST AND CRICKET. RED-LEGGED LOCUST (MELANOPLUS FEMUR-RUBRUM) ... . JAPANESE CAGES FOR STRIDULATING INSECTS . . PROBABLE STRIDULATING ORGANS ON ABDOMINAL PLATES OF CATE Se Gn ca ay ee THE FACE OF AN ANT, SHOWING THE FLEXIBLE ANTENNZ THE CHALLENGE WITH CROSSED ANTENN/. . A QUEEN ANT SURROUNDED BY HER COURTIER GUARD A PEEP INTO AN ANT COMMUNE .... . WORKERS TAKING EGGS FROM THE QUEEN MOTHER ; ATA t QUEEN BROUGHT HOME << 45 sc) ee. 2 © = « AN EMMETT NURSERY FOR THE YOUNG. . . 2... 2. 206 « YOUNG WINGED QUEEN OF HONEY-ANT .... . A MARRIAGE-FLIGHT, OR ‘“‘SWARM,’ OF WINGED MALE AND RRA PPA NGI. Ws isk ccs a Pee ARRIVAL OF THE FOOD-BEARERS AMONG THE WINGED DE- EM PETE MMR pce Sac, oP el oe, Salpaee | ede mae ERAENE OF ANTS ©. 6.0 » *. : ~ : ° 5 ~ ? s t : { ' » + . 4 ~ - a 4 ANT COMMUNITIES CHAPTER I FRATERNAL CONFEDERACIES AND COMMUNAL RIGHT- EOUSNESS AMONG SOCIAL ANTS RGANIZED society, whether among insects or men, implies some form of government; and that implies citizenship. And fidelity to the just and natural service of citizens is communal righteousness. May we apply such a term to insects? And if so, what is the character of such a quality; or, if one may venture so to put it, what is the quality of such a character? And is it in any measure comparable with communal right- eousness as the phrase goes among men? The inquiry will here be limited to ants; but the study requires the statement of some preliminary facts, so that readers may have a true conception of the field which our thoughts are to explore. Some insects are “‘solitary”’; they live alone. Others are ‘“‘social’’; they live in communities. There is such a striking contrast between the manners of the two groups that one wonders how the distinction arose. True, at the beginning of life most insects are massed, since their mothers lay their eggs in compact clusters. But if one start with the theory that this may have left 1 ANT COMMUNITIES in the germ of being a tendency which, under favorable conditions, might be transferred to the adult, he is met by certain facts that may confound his reasoning. For example, the eggs of ants and bees are dropped separately, yet they produce insects of the strongest social habits. The moth of the tent caterpillar oviposits in clusters, and her progeny keep together in the larval state. The eggs of the garden orbweaver, like those of most spiders, are laid in carefully sheltered masses, and the young are partly reared together in the silken tent which the mother overspins. Moreover, they start in- dependent life in a self-woven silken compound. The lycosid, a ground -spider, drags her round cocoon be- hind her until the eggs are hatched, and then bears the younglings about clustered upon her back. Yet soon the centrifugal factor in vital force drives the young of moth, orbweaver, and lycosid asunder, and thereafter their life is solitary. With social insects the tendency is reversed. Be- ginning life solitary, as in the case of the maternal founder of an ant’s nest, the individual becomes a family, and the fainily a community, and this may develop into a vast commonwealth containing many thousands or even millions of individuals. When the circle of life is complete, the vital centripetal force which binds these communities together is relaxed, in a movement of im- passioned communal fervor, to allow the outgoing of the winged males and females, as with ants; or the swarming of a new community, as with bees. This is the “com- mencement”’ time in the insect calendar, when a matured sliver of the community is struck off and pushed into independent life. Among ants these communities vary in population 2 FRATERNAL CONFEDERACIES AMONG ANTS from a few score to many thousands. There are villages, towns, cities—each, for the most part, independent of all others, and each complete within itself, a separate tribe, a sovereign state. That the orderly and successful conduct of such communities must spring, consciously or unconsciously, from some system, is self evident. What is that system? What are its laws, its customs, its methods of administration? Is an ant-hill a mon- archy, a republic, a democracy, a socialistic commune? How does its government compare—if in any wise com- parable—with the civil governments of men?, And what lessons in civics can we learn therefrom? Surely, an interesting inquiry here opens up; for, whatever the result, it must give us a glimpse of nature pure and simple. To this the author’s purpose is mainly directed; but, as a by-product of his studies, he con- fesses a keen interest in those reflections that traverse the field of human civics, and which inevitably arise as one pursues the history of life in ant communes. In many parts of the Alleghany Mountains, and in middle and eastern Pennsylvania, in New Jersey, in the White Mountains and elsewhere, are distributed the large conical nests of the mound-making ants of the Alleghanies, Formica exsectoides (Fig. 12). These vary in size from newly begun colonies a few inches high to mature hills, measuring thirty-seven feet in circumfer- ence at the base, though rarely more than three feet high. They occur in groups; and in one site near Holli- daysburg, Pennsylvania, within a space of fifty acres, the writer counted seventeen hundred well-developed mounds. At two other localities in these mountains sim- ilar groups were observed even more thickly placed. At “Pine Hill” about thirty acres were occupied, of which 3 ANT COMMUNITIES five were found to contain two hundred and ninety-three mounds, an average of fifty-nine to the acre, or eighteen hundred for the whole section. At ‘‘Warrior’s Mark ” WON EN v ae Mirae i DIY WOVE) Ip He ‘ WY AL hee. WEYL 00 § We Y,* bane SON ae Lan Mn WM YY Whe ) WN 34 Mi Fig. 12—A GROUP OF MOUND-MAKING ANTS’ NESTS (Formica exsectoides) another large settlement of nearly two hundred hills was visited. Experiments made in the Hollidaysburg group proved that all therein formed substantially one community, in complete fellowship, although the in- 4 FRATERNAL CONFEDERACIES AMONG ANTS dividual mounds appeared to be conducted indepen- dently. The following will illustrate these experiments. [McC. 2, p. 282.]? A small oak-branch covered with aphides and their attendant ants was broken from a tree and _ placed erect upon a mound twenty rods distant. It was thought that if anything would incite to hostility, it would be the intrusion of members of a separate com- munity upon a congener’s feeding-grounds. On the contrary, the ants being called from the hill, came out and mounted the branch with the usual excited bearing, and then mingled with its original occupants on friendly terms, and began to feed quietly from the galls and aphides. A larger branch having many more ants upon it was cut, and planted upon a mound a consider- able distance beyond the first one. The insects were called out by tapping upon the surface. The usual whirl of angry sentinels and other workers followed, and then all blended with the intruded ants without a sign of hostility. A spadeful of earth was swiftly cut from the mound, and with ants, cocoons, and broken cells, thrown into a pail, carried to a cone fifty rods distant, and cast upon the surface and around the lower gates. One could not distinguish between the citizens of the two mounds as masses of excited ants poured out and began their usual movements, but no marks of hostility appeared. After the first sharp challenges with crossed antennz the imported ants melted away into the general com- munity as though at home. The only other test of this nature which need be mentioned was made with three hills (D, E, F), to 1 See ‘‘ Table of Authors,’’ Appendix. 5) ANT COMMUNITIES which reference will be made hereafter as the “hysterical hills,” on account of the abnormal state of excitement which marked their inmates, and for which no reason was apparent. Large pieces of the mounds D and FE, which were twelve feet apart, were interchanged, tossed violently from one to another. Although swarming with insects intensely agitated, there was no appear- ance of hostility at either mound. I then proceeded to F, one hundred and fourteen feet distant, and called out the ants until the cone was fairly black with them. From the densest centre of life was cut out a section about six inches square and borne hurriedly to D, catching en route the dropping ants in a hat. The contents of shovel and hat were thrown upon the cone in the midst of its hosts of in- habitants. Even this violent invasion which, with an alien species would have been a signal for war and slaughter, was not resented. There were sharp antennal challenging and quick response, and then the new- comers melted away into the mass of their enforced hosts, as fellow-citizens “‘to the manner born.” There was complete fraternization, which was not afterward disturbed by any breach of the peace. The final test was an artificial nest prepared in a large glass jar within which earth, sticks, and surface litter were placed. Ants taken from a number of mounds situated in parts of the field and wood most remote from one another were put in. Cocoons from yet other cones were added. Aphides, water, and honey were then given them. This miscellaneous assemblage united with the utmost harmony in building galleries, caring for the cocoons, and defending the nest from intruded ants of separate species and from spiders. From time 6 FRATERNAL CONFEDERACIES AMONG ANTS to time ants and cocoons collected from widely separated hills were put in, and these were always and at once adopted. This amity and co-operation in the duties and responsibilities of good citizenship continued until the composite republic of drafted citizens was broken up. The natural explanation of these rare conditions is this: the antennal interchanges between the various parties at once showed that all were fellow-citizens of one commonwealth, equally entitled to communal wel- come and place, which were accorded at once upon the recognition of the one common nest-odor which is the badge of citizenship. Thus it appeared (and to the writer it was then an astounding revelation) that among the myriads of creatures occupying these more than seventeen hundred mounds there was complete fraternity—if, indeed, they were not one mighty confederacy! Here was a republic which in the number of its separate states—for every mound was an independent community of ants—and in the multitude of its total population exceeded the most sanguine prophecy of the future American republic. It would be hard to conceive of anything like local or communal loyalty, an inflated devotion to ‘“‘state rights,” or that jealousy and conflict of interests which are apt to develop among neighboring communities, as leading on to war among the insect commonwealths which were the subjects of the above experiments. If a city be (as it has been defined) ‘‘a place inhabited by a large, permanent, organized community,” the name ‘Ant City,” by which it is popularly known, is fitly given to this vast concourse of united emmets, or, indeed, to any one mature colony thereof. Naturally the question often occurred, How many ants are here 2 if ANT COMMUNITIES assembled? An exact census in such a case is im- practicable, but at least a reasonable approximate is possible. Dr. August Forel, the eminent Swiss myr- mecologist, has described a community of two hundred mounds of a closely related species (Formica exsecta) among the mountains of Switzerland, as having each a population ranging from five thousand to five hundred thousand. If one were to apply the lowest estimate (five thousand) to our American community, it would give a total population of eight and a half million living creatures! That is quite enough to justify their claim to the title of “city,” but, in truth, a conservative esti- mate would make them many times as numerous. In his Die Nester der Ameisen (Ants’ Nests) [F. 4 and 5], in commenting on my observations upon this sodality of the Alleghany Mountain ants, Doctor Forel says: “These ant kingdoms have, in all probability, a popula- tion of two hundred to four hundred million inhabitants, all forming a single community, and living together in active and friendly intercourse.” Think of it! A population equal to that of the whole empire of China! And this isnot a wild guess of an enthusiastic vision- ary, but the sober calculation of the veteran chief of Ku- rope’s myrmecologists, and one of its foremost medical specialists. I have spoken of this mighty concourse of organized insects as a city; but doubtless kingdom, or empire, might be a better title, for there was through- out the settlement a marked tendency to groups of mounds of different sizes, which might represent the cities or large centres of population distributed through- out a commonwealth. No North American ant exceeds these mound-builders in the size of the structures reared by them. But in 8 FRATERNAL CONFEDERACIES AMONG ANTS some tropical lands even larger mounds are found. Livingstone speaks of ant-hills in South Africa that dotted the face of the country like haycocks in a harvest- field. In the woods they were twenty feet high and forty to fifty feet in diameter! [Li. 1, p. 590.] These rival the great gothic erections of the termites. Whether the African ants show the communal unity that exists among our Alleghany mound-builders has not been determined. But such unity must obtain among the vast hordes that occupy each hill. One who studies the economy of these communes soon notes a well-defined division of labor among the three worker castes—27z., workers-major, workers-minor, and minims or dwarfs. There are sentinels or police- men, masons or builders, foragers, nurses, and courtiers or queen’s body-guard. These are not so differenced as to form fixed classes which embrace always the same individuals with duties limited to one sort of service, as is the case in some other species. Apparently, all branches of service have recruits from all the castes, and these pass from one duty to another at will. On the surface (as far as human intelligence discerns) it is a ““o9-as-you-please’”? arrangement, which nevertheless is dominated by some occult principle that brings orderly results out of seeming chaos. There appears to be no specialized warrior caste among these formicans, but there are sentinels, or policemen, whose duty it is to guard the community from hostile approach. Their internal affairs call for no domestic police. Among these millions of citizens there is not one criminal, not one degenerate! I do not recall, in all my long and varied observations, a single example of an ant whose actual offending called for the administra- 9 ANT COMMUNITIES tion of civil punishment. Nor do I remember to have read of such a case in natural history. Emmet out- lawry is unknown. These vast communities are self- policed. Their citizens are so perfectly self-controlled, so absolutely free from even the desire to violate law, that as against them a domestic police would be a sine- cure. Do you look for the perfect social commune whose citizens are all perfect in that ‘“‘righteousness which is of the law’? One may find it here. But public enemies abound. Eternal vigilance is the price of peaceful industry and security. Here are millions for defence, though not an ant be needed to support home government. And to this end every citizen, if need be, is a soldier-policeman. Watchmen continually guard the various gates, or entrances, to the cone, most of which are ranged along its base just above the ground, but some are placed between that and the summit. These sentries lurk inside the gates, whence they issue, with every mark of intense excitement and watchfulness, if one approaches a finger or drops some object near them. Frequently they patrol the vicinity of the gates, and attack intruders with promptness and intrepidity (Fig. 18). Fig. 13—WATCHMEN AROUND THE GATE OF This is a Sas A Owe ee alent manner of ants. There is but one large tubular entrance to the pound-cake-like mound of the honey-ants of the Garden of the Gods (Myrmecocystus hortideorum) in Colorado. Around its upper rim, with their yellow heads and quivering antenne 10 FRATERNAL CONFEDERACIES AMONG ANTS just in view, one sees a ring of sentinels. At the door into the pebble-sheathed cone of the occident ant (Po- gonomyrmex occidentalis) of the American plains, which opens into the breast of the cone, the watchmen wait, intent and vigilant. So it is elsewhere, and almost everywhere, that ants are found in large communities. It is the law of emmet as it is of human society, that “Some must watch, while some must sleep; So runs the world away!” These watchmen do not always belong to a soldier caste. Every emmet citizen who has passed the brief callow stage of first emergence from pupahood is a policeman or soldier on occasion, and may, as far as the facts now appear, go on sentry as on any other duty. It would not be strange if, in the gradual development of such a social system, certain individuals should have shown special aptitudes for police service that kept them more or less continuously therein, and so have arisen something like a soldier class. In some species such has been the case, as with those of the genus Pheidole, and the leaf-cutting or parasol ants of Texas. But it is not so with our mountain mound-builders. They remind one of the militia organization of our earlier frontier States—Ohio, for example, which made every adult male, not disqualified by age or otherwise, subject to military duty. Indeed, such is, in theory, the relation of all citizens of the American republic to the general government. Among our ants that duty is never dodged. There are no desertions. Lazy, cowardly, and skulking ants one does not see. With heartiest good-will the call to service is met, and a “clear call,” apparently, is simply a perception of the commune’s danger and need, 1 ANT COMMUNITIES Then, at a touch, every citizen becomes a warrior, and the outer walls swarm with defenders. Here one may note a remarkable trait of these ant citizens—their devoted patriotism. At the approach Fig. 14 GROUP OF TWO MOUNDS OF F, EXSECTOIDES AT AL- GONAC, ST. CLAIR RIVER, MICHIGAN (Photo by William 8. Cooper, Detroit) of an enemy they attack it, absolutely regardless of con- sequences. The personal factor has no place nor even consideration in the act. Whether the supposed hostile be great or small, beast, bird, creeping thing, or man himself, the brave little creatures fling themselves upon it with the utmost abandon. For example, here comes to the edge of the mound a large black carpenter ant (Camponotus pennsylvanicus), a ferocious and formidable insect, almost twice as large as the formican and a hereditary enemy. Forth from a gate leaps a sentinel, and launches its quivering body straight against the sable giant. One snap of the Camponotid’s jaws, and the assailant’s brown head is 12 FRATERNAL CONFEDERACIES AMONG ANTS severed, and its beautiful life extinct. Another sentinel follows, and another, only to meet the same fate. But others crowd to the combat, eagerly facing and meeting wounds and death. Overwhelmed by numbers, the black warrior is at last conquered and dragged into the formicary, where its dismembered body is sucked dry and its shelly parts dumped upon the refuse-heap, or mayhap built into the growing walls, along with vegetable débris of various sorts. This courageous and unselfish disregard of person and absolute devotion to the communal safety at the cost of life or limbs is characteristic of ant citizens; not of a few, but of all; not rarely and occasionally, but always; not under compulsion, but freely and without Fig. 15—-SINGLE MOUND OF F, EXSECTOIDES, BRUSH MOUNTAINS, PENNSYLVANIA reward of any sort. Not even the high stimulus of applause of comrades and of honors from their fellows urge and sustain them. Such conduct is so much a 13 ANT COMMUNITIES matter of course that no one notes it as extraordinary, and a war-scarred veteran may be seen dragging its maimed limbs into action, or in some obscure corner licking its hurts and waiting for the end without nurse or comforter. It has done its duty, and accepts the result with imperturbable unconcern, as do its fellows. Apropos of these studies of police administration of our ant commonwealth is an observation incidentally made while conducting experiments to determine the mode of recognition among ants. Starting upon the theory that it was a specific odor or emanation analogous thereto by which our mound-makers recognize one another, the matter was tested by subjecting individuals to baths of clear water, and infusions of wintergreen, cold coffee, and tea, and then returning them to their mounds. ‘The individuals thus treated were immediate- ly attacked by roundsmen, a dozen or more sometimes, and dragged away like culprits. These assailants were then taken with their victims, submerged, and festored to the hill with the same result. So with a third series; the assailants of the assaulted ants were in turn attacked, and invariably the same measure meted to them that they had measured to others. They had lost, for the time at least, the ‘““mark” of .their citizenship. [McG 2. p28.) In some cases the parties assailed were soon released, as though the mistake had been perceived. But for the most part there was every indication of a mortal purpose and a fatal issue. It was here that a curious trait was developed. The demeanor and conduct of the immersed and ‘‘tainted”’ ants were in marked contrast with their character for valor in battle and pluck generally. They were quite passive under the fierce 14 FRATERNAL CONFEDERACIES AMONG ANTS assault of their fellows, and sueceumbed with little or no effort to resist. They seemed to have the carriage of persons detected in some meanness or crime—a “‘hang- dog”’ sort of air. Could it be that these unfortunates tacitly recognized the fact that they had become obnoxious to the com- munal police? And, although this had come about by no fault of their own, was their instinctive sense of obligation to submit to the “legal authority” which dominated the commune so imperative that they yielded themselves to their fate, temporary captivity or death as the case might be, without the least show of resistance? QOne’s Judgment is so apt to be biassed by his interest in and sympathy with these wise little creatures that he is inclined to distrust even his most careful observations, and fear that unconsciously he may have interpreted their behavior by the operations of his own mind. But in this case so many tests were made, all yielding like results, that the above conclusion seemed to be justified. ; And why should it not be so? The higher animals are not insensible to the public sentiment of their kind, as one may see from the actions of domestic flocks and herds and of gregarious wild beasts. It is what might be looked for in social insects, though therein less notice- able by human senses; for ages of hereditary com- munal life must have wrought upon their sensibilities, so keen in certain quarters though defective in others, a marked response to an environment of active dis- approbation. One does not speak of this as a conscience, perhaps not even as a remote analogue thereof. But it seems to take the place of that sentiment, or experience, or inward 15 ANT COMMUNITIES impulse and restraint In man, without which no com- munal government is long possible. What is it that imparts to our genus elements of chaos, crime, misrule, and misery so far beyond the qualities of social insects (if also so vastly above them), and which starts up in the path of history records of communal disorder that one seeks in vain among ants, hornets, and wasps? Why should a creature with a conscience ever be less steadfast and exemplary in communal righteousness than a citizen of a commune of mound-making ants? CHAPTER II NESTING ARCHITECTURE—HOUSING THE COMMUNE HE housing of the commune is a duty that springs up side by side with the existence of the commune. In the typical beginning of an ant community by the single fertilized queen, the first act of the incipient foundress is to scoop out and heap around her, in earth or wood, a cell whose diameter is somewhat greater than the length of her own body. This is the rudimen- tary house of the commune—the primitive cave which bounds the architectural aim of most animals, and which is the starting-point with man himself (Fig. 16). With great numbers of species, this cave will be found under a stone. A flat stone, not too large and not deeply imbedded in the ground, if lifted up in the early spring, or at any time during summer, will be found to serve as a rocky roof which overspreads the vestibule and protects certain galleries, halls, and passages into an underground formicary. The mere fact of choosing such a location for a nest is significant; for, besides the protection and defence afforded, the stone absorbs the sun’s rays and serves thus as a natural furnace, con- tributing to the warmth of the ants and of their imma- ture young. Like the ancient catacombs of Rome, which served primitive Christians equally for home, for sanctuary, and for cemetery, these subsurface chambers and Wi ANT COMMUNITIES galleries are arranged in irregular stories, one above another. They are simply the primitive cave in multiple, with intercommunicating passages. And they increase on the principle of any other social settlement—to meet the communal growth. Many of them reach immense propor- tions; most of them are comparatively small, SS ee With the great ee as ‘ete: army of woodwork- ers the same simple type of architect- ure prevails, modi- fied simply and not largely by the ma- terial from which the public build- ings are wrought. The storied subdi- visions especially Ce ee 3 are crowded within (By courtesy of the American Museum of Natural History) 9% narrower space Fig. 16—oRIGINAL CELL OF CARPENTER and are less dis- ANT QUEEN, AFTER WHEELER tinctly marked. One who carefully studies the architecture of a long-established nest of carpenter ants will find himself unconsciously tracing out in miniature pillars, arches, aisles, vaults, and domes of different orders of architecture. It takes but a slight stretch of fancy to imagine that one is gazing upon the ruins of an ancient seat of a diminutive type 18 NESTING ARCHITECTURE of his own race, who had carved out their toy-like homes and temples in the solid wood. One of the most interesting examples of the storied type of underground architecture is that of the honey- ants of the Garden of the Gods (Myrmecocystus hor- tideorum), Colorado, the farthest north they had been observed. The approach to their nest was a small, low, pebble-covered mound with a large central gate which penetrated it vertically for a few inches, and then was diverted into various passages that followed the slope of the ridge on which the colony was planted rig: 17). In one nest, chosen for complete exploration, excava- tion was carried forward during three days and several Fig, 17—EXTERIOR ARCHITECTURE OF HONEY-‘NTS OF THE GARDEN OF THE GODS (Myrmecocystus hortideorum) parts of days, two men working with mallet and chisel and with knife in the soft, red sandstone, or “ pudding- stone,’ of which the ridge is composed. The entire length of the formicary was seven feet eight inches. 1 Nature’s Craftsmen, p. 120. 19 ANT COMMUNITIES The point at which it ended was forty and a half inches below the level of the main gate and twenty-nine and a half inches beneath the level of the hillside. In all, the ants had excavated thirty-six cubic feet of rock, and this space was honeycombed with galleries and rooms. The latter varied from five to six inches long, three to four wide, and about three-fourths of an inch high. The walls and floors of these rooms were smooth, but the roofs were left in their natural roughness, thus forming a better foothold for the rotunds, or honey- bearers, who were perched upon them, clinging thereto with their claws, and closely clustered together. [McC. 4. pp. 30) of.| The occident ant (Pogonomyrmex occidentalis) is closely related to the agricultural ant in structure and habit (Fig. 18). But the typical forms vary decidedly in their exterior architecture, the occident having its commune overbult with a prominent cone coated with pebbles, while the typical agricultural keeps the space around its gate free from all growth. Both species, like the mound- making ants of the. Alleghanies, are among those that found and maintain vast communities, and therefore have a special interest to us in our present studies. Their homes are often wrought in a tough clay that is almost as hard to excavate as the red sandstone of the Garden of the Gods, and equally taxes the resources of the workers. The arrangement of rooms into stories is here also carried out, and to a surprising extent. In one nest of the occident ant a story was found at a depth of over eight feet beneath the surface (Fig.!99). Those who are curious in such comparisons might find grounds here for a striking parallel between the achievement of an ant three-eighths of an inch high 20 NESTING. ARCHITECTURE (long), and of a man one hundred and seventy-six times as high (five and one-half feet). [McC. 4.] Were we to reckon a proportionate rate of progress between the two on the basis of height, our man would have to Fig. 18 —A CONNECTED SERIES OF STORE-ROOMS (A, B, C, D), OR GRANARIES AND CHAMBERS OF THE OCCIDENT ANT * be credited with a storied structure one thousand four hundred and eight feet deep. Apart from such fanciful comparisons, it is certainly well calculated to excite our wonder that such insignificant creatures can, by their united exertions, bring about results relatively so vast, unaided by mechanical contrivances. The numerous chambers which in honey-ant structures 21 — 19—INTERIOR OF A STORIED COMMUNE OF THE OCCIDENT ANT OVER EIGHT FEET. DEEP Fi NESTING ARCHITECTURE are occupied by those living honey-pots, the rotunds, in the occident nests are used as store-rooms. Herein one finds various sorts of seeds put away for food. In a few cases rooms were found filled with husks and apparently sealed up, as if empty spaces had been utilized in the rush of business for “ dumping-grounds,”’ to save transporting the waste matter of the seeds to the outer gates and the kitchen-middens. Perhaps these “relief chambers” were merely a temporary makeshift, and would have been cleared out in due course had not the commune suffered a destruction as dire as that of ancient Troy or Carthage. Such great structures as have been described here imply the work of years, and it is probable that some of them were several years old. They showed every mark of such age; in fact, the continuous life of an ant community, in such sharp contrast with that of our hornets and yellow- jackets, which do not survive October, would naturally demand permanent or con- tinuous residences, the permanency of the community and the permanency of their dwelling going naturally hand in hand. By calculations made from the levelled floors of the mountain charcoal-burners, which had been occupied by large mounds since their abandonment, I concluded that some communities of Formica exsectoides were at least thirty years old, and I believe that they remain active for a longer period if unmolested. Livingstone (South Africa) speaks of ant-hills which dotted the face of the country like haycocks in a harvest- field. In the woods they were seen twenty feet high and forty to fifty feet in diameter. He also notes the fact that these spots are more fertile than the rest of the land, and are the chief garden ground for maize, 3 23 ANT COMMUNITIES pumpkins, and tobacco. This statement has a signifi- cant bearing upon the part assigned in nature to ants and other insects in making the earth habitable by agricultural man. [Li. 1, p. 590.] The pebble roofing of the cone of the occident ant is a permanent feature (lig. 20)—at least, of the immense number seen by me, all were covered with pebbles of the gravelly soil in which they stood. In the vicinage of the Garden of the Gods the pebbles were red sandstone. The mounds in Wyoming observed by Prof. Joseph Leidy were covered with a white stone. Mr. R. Hill saw them Fig. 20—-PEBBLE-ROOFED COMMUNE OF THE OCCIDENT ANT on the Sapa Creek, in northwestern Kansas, roofed with pellets of the limestone rock in which the great fossils are found, and in one or two cases even of portions of the fossils. Thus the conditions of the famous riddle of the Judean Hercules are repeated in this far Occident, and the hymenopterous allies of the bees who nested in the skeleton of Samson’s lion burrow and build a home o4 NESTING ARCHITECTURE among the bones of extinct creatures of the geologic ages. | These roofing pebbles are not (or but sparsely) inter- mingled with the soil of which the interior bulk of the cone is composed, but form a stone covering, or roof, about a half inch thick, more or less. Mr. H. L. Viereck in- formed me that he had seen bits of cinder and coal, evidently gathered from the railroad track, for roofing. This is confirmed by the statement of Mr. G. A. Dean [D. 1, p. 169], who further says that on the old town site of Wallace, Kansas, they used bits of glass, mortar, and small fragments of rusted iron from the débris of ruined houses. Thus the roofing habit, though it may have originated from the accidental deposit of ex- cavated pebblets, seems to have grown into a fixed purposeful instinct that prompts to gather supple- mentary material from any available quarter. The pebbles are handled with ease by the worker- ants, who nip them with their outstretched mandibles and then move off, rarely stopping en route to adjust the burden or to rest. The body is lifted up, the head well elevated to prevent bumping against the surface, and the load held well to the front or somewhat beneath the body. The portage was amply observed during ordinary excavations, in opening and closing gates, and in repairing breaks caused by rains or purposely made for experiment. In the last-named work the ants would descend to the clearing at the base of the cone, and carry the stones up the slope with as little apparent effort as when moving downward. This, however, must be an easier task than transport- ing them from distant sites or from their interior beds up the galleries to the surface. The space traversed in 25 ANT COMMUNITIES this underground portage is sometimes equal to a per- pendicular distance of nine feet, which has little me- chanical relief from the inclination or roughness of the gangways. Some of the pebbles have from six to ten times the weight of their carriers. I never saw any copartnerships in these portages. No ant came to aid a struggling worker, and none seemed to need assistance. I have often admired the vigor and skill shown by baggage-porters in shouldering and bearing up several flights of stairs the immense trunks which American ladies take with them on their travels. But here, if we may be indulged in the comparison, is an insect three-eighths of an inch long (and the worker-minors are shorter), who can carry up sharp inclines and perpen- dicular surfaces, over a distance three-hundred times its length, a burden six to ten times its weight. If, as heretofore, we estimate the average man at five and a half feet in length and one hundred and fifty pounds in weight, our baggage-porter would needs carry a half- ton trunk up one-tenth of a mile of stairway, to meet on equal footing the emmet athletes of the occident ant- hills! The simplest type of ant architecture, as we have seen, is a single cave excavated in the earth, or in wood, or formed by detritus cemented by salivary secretions. This grows into (second) an enlarged chamber or cham- bers, with vestibule and connecting galleries. Thence (third) developing downward, the simple cave or con- nected chambers have grown into vast and deep-storied rooms and avenues, like those of the agricultural, oc- cident, honey, and cutting ants. Expanding in the opposite direction—a development upward instead of downward—(fourth) the little heaps 26 NESTING ARCHITECTURE of earth-pellets (Fig. 21) thrown out around the gate of the cavern home of Pheidole, or the garden Lasius, be- come (fifth) the great conical structures of the mound- making ants of the Alleghanies, which are in themselves true habitations. This is an important difference. The cones are thoroughly honeycombed with avenues and rooms, streets and galleries, which are the actual living- quarters of the commune, and form, each mound in it- Fig. 21—iLITTLE HEAPS OF EARTH-PELLETS THEOWN UP SEOUND THE GATES OF PHEIDOLE PENNSYLVANICTS, THE SIMPLEST TYPE OF &ANT-WOUND self, into a densely populated city, although in full alh- ance of citizenship with all like mounds in the vicinage-. We come now (sixth) to a type of structure which characterizes a number of genera in Europe and America, but which is particularly developed in vanous species and varieties of Cremastogaster. The species of this genus are small, and are widely distributed throughout our territory. They have a heart-shaped abdomen or gaster, flat above and rounded below, and this they have the odd habit of turning up and directing forward ANT COMMUNITIES (Fig. 22), so that it is almost parallel with the line of the thorax. ‘[McO.-9) p. 168;] These ants, besides nesting in the earth near the surface and under stones, are apt to choose a site in a Fig. 22—cREMASTOGASTER LINEOLATA a, b, c—Worker. d, e—Queen. /—Worker with turned-up gaster. heap of stones, on an old stump, or in the débris of fallen and de- caying logs. A colo- ny settled among the crannies of a bowlder wall at our country home, Brookeamp, had built a covered ap- proach to their main entrance, using there- for particles of dust, earth, etc., that had accumulated upon the rocks. The nest itself was within the inter- stices formed by the rounded exteriors of the big bowlders, and was quite out of sight. This covered vestibule was a mild suggestion of the vast mud-cov- ered ways made by the Eciton, or “driv- er ants,” to cover their route when out upon one of their devastating forays. On a vine twined about the cloistered porch connect- 28 (By courtesy of the American Museum of Natural History) Fig. 23—cARTON COCCID-TENT OF CREMASTOGASTER LINEOLATA- PILOSA PERGANDE. (After Wheeler) NESTING ARCHITECTURE ing my city manse with the church, I have noted similar enclosures built around the stock at points where a branch diverged therefrom. They were apparently wrought out of ‘‘carton’’—that is, a combination of wood-dust, loose earth, minute particles of straw, hay, and horse-feed (the droppings of passing animals), such as drift from the street into corners and crevices of walls and upon the foliage of city plants (Fig. 23). This material had been mixed into a sort of mortar and fixed by a natural cement secreted by the ants, until it formed a woody composite that easily crumbled between the fingers, but held together well enough to answer its purpose as a temporary tent. Structures of a similar character have been observed around the bases of the needle-like leaves of pine-trees in New Jersey and else- where. To what purpose are these rude shelters made? Chiefly to obtain exclusive and undisturbed possession of aphides and other insects that excrete the honey- dew of which they are so fond. [W. 9, pp. 1-18, Plate ii. copied.] This enclosure not only serves to restrain the insect herds from wandering to inconvenient sites, but shuts out alien ants that, when strolling about, as is their wont, in search of food, might happen upon the pre-empted aphidian flock, and encroach thereon. In short, it is the Cremastogaster’s way of ‘‘staking her claim.”’ It is interesting to notice that this tendency to build carton tents exists in this species not in full vigor as a thoroughly developed and fixed habit, but as a sub- sidiary tendency, a survival, it may be, of an ancestral habit once strong and persistent, but which, in course of time, has been gradually weakened and well-nigh 30 ASTEBOARD NEST OF DOLICHODERUS BITUBERCULATUS P Fig. 24 MAYR, FROM BANKOK (After Forel) ANT COMMUNITIES atrophied. Still, under the stimulus of special favoring conditions, the latent ancestral tendency springs into active force, and shows itself in the occasional and temporary structures above described. I have alluded to this phase of ant industry and vent- ured on the suggestion of its origin, not simply because of the intrinsic interest of the facts, but because they lead up to what is (seventh) a distinct and well-defined form of nesting architecture. Not only Cremastogaster, but other genera have acquired the habit of making carton nests in and upon trees. They are at times quite large (a foot or more in diameter), and they form true habitations, as are the nests of hornets, in which larvee are reared, dependents housed, and all the functions of an ant commune carried on. These tree-dwellers are for the most part habitants of tropical and subtropical countries, and the accounts of travellers give one a vivid conception of their power, when excited by intended or accidental aggression, to swarm forth in legions from their domiciles and punish invaders with stings that seem pointed with fire. Of the ants of this form of arboreal nest, Fig. 24 is taken from Dr. Forel’s Anis’ Nests, and shows a paste- board nest of Dolichoderus bituberculatus Mayr, taken from the bough of a tree from Bankok, Siam. Fig. 25 is a tree-nest after a figure published by Dr. von Ihring [Von I.1, p. 334] of Camponotus rufipes, of South America. We come now to note (eighth) the existence of nests for which the framers have called in the use of silk. That this should turn up at even the most unexpected points in the insect world will not seem strange to one who knows how largely the spinning habit enters there- into. Many ants in their larval forms follow the role 32 Fig. 25—NEST OF CAMPONOTUS RUFIPES ON A TREE (After Von Thring) ANT COMMUNITIES of other orders, and spin themselves within their tough pupa cases or cocoons. Thus we are quite prepared to learn of Professor Forel’s Ceylon species (Polyrachis jerdonii), which builds upon leaves a small nest com- posed of pebbles and minute fragments of plants, cemented together by a fine web, or woven together to form a web-like wall of bright grayish brown. In the East Indian ant Polyrachis dives the nest wall is a pure silken web of a brownish yellow, by which the enclosing leaves are lined and bound together. Polyrachis spinigera, of Poonah, India, makes for its nest a fine brown silk web pliable as the finest gauze, but thicker. This is fixed on the ground, where it forms the lining of a funnel-shaped cave that widens out into a chamber. But among the woven ant-nests thus far made known the one that seems to show the highest type of nidification is that of Acophylla smaragdina, a com- mon ant of tropical Asia and Africa. The workers are large, long, reddish to greenish in color, of a war-like and fiery temper. Their females are grass-green, their males black (a rather striking color combination), and they maintain populous communes among the branches of trees. The common habitation is formed by joining together the borders of leaves with white spinning-work and binding them into a large mass, something after the fashion of certain spiders and tent-caterpillars. According to Mr. Aitken [Ai. 1, p. 422], the method of construction is as follows: A worker stands at the point where two adjoining leaves diverge, and holding to one with its claws, seizes the other with its jaws and draws the two together. As the leaves gradually approach each other they are held in place by the outspun threads, 34 NESTING ARCHITECTURE until, as the leaves touch and overlap, they are overspun and firmly bound down. And so the work passes from leaf to ieaf until a sufficient housing is provided. This process in essential method resembles that which I have studied among spiders, particularly those large native orb-weavers, like Epeira insularis and EH. domuciliorum, that build as a domicile large leaf-tents above their great geometric orbwebs. It seems almost past belief as a bit of natural archi- tectural ingenuity, but the observer, whom Professor Forel thinks entitled to credit, states that if in clamping the leaves the space separating the edges be overwide for one ant to manage, other workers, from two to five in number, will ‘‘join hands” to form a chain, each grasping the body of its neighbor until the last link on one side holds a leaf in its mandibles, while the last link on the other side grasps a leaf with its claws. Thus, all drawing together, the chain is gradually shortened until the breach is closed and spun over. When enough leaves have been fastened together, the whole is over- spun with a compact silk web, and made water-proof. It is then divided into connected living-rooms as required. Many ants are opportunists in the choice of a habitat. Instead of working out a nest in earth or wood, they exercise a sort of ‘‘squatter sovereignty,’ and preempt for use some available locality. For example, I found a large commune of A phenogaster tennesseensis in an old pine-tree stump at Bellwood, Pennsylvania. Moss and lichens grew freely upon the stump and its great bare roots. In the scant soil that had formed upon the top sundry wild plants were growing, as in a roof- garden. At various places over the surface large, dry 9 395 ANT COMMUNITIES toadstools were attached, looking like ancient sea- shells. Within these the ants had settled. The in- teriors swarmed with workers and larvee: and, as evi- dence that the task of enlargement was going on inside Fig. 26—NEST OF PSEUDOMYRMA BELTI ON MEXICAN ACACIA THORNS ’ of both toadstools and stump, the outer bark of one large root was covered with fresh wood-dust. In tropical and subtropical countries examples of this habit are common on certain thorn-bearing trees and shrubs, as the Acacia. These thorns are often quite formidable in size. I have had specimens of them which had been inhabited by ants of the widely spread genus Pseudomyrma. Near the points circular gates were ie 372 See eut out for entrance and exit, and MA BELTI (emery) the commune was established in the mari cits hollow interior (Figs. 26 and 27). It is believed that some ant-inhabited plants, as Cecropia adenopus, furnish in themselves a supply of 36 NESTING ARCHITECTURE food in small pyriform or ovate albuminous growths (Miller’s corpuscles), which are eaten by the insects, ap- parently without disadvantage to the tree. They present another example of that interesting form of symbiosis— a comradeship of support and defence—which not infre- quently exists between plants and insects.1. For in return for the nurture yielded by the plant, the ants protect them from the incursions of such enemies as the leaf-cutting Attide, that defoliate them in their leaf- hunting expeditions. 7 Our studies of what, for lack of a fitter name, has been called the “architectural”? and “engineering” skill of ants will now return for a while to the great confederacy of the communes of mound-making ants. Let us note the citizens of this large colony of Formica exsectoides, who are adding a story to their communal cone. It isa lively and interesting scene. The utmost activity pre- vails, greatly quickened by a smart shower which has made the building material more available for use; for hot, dry weather had left the soil powdery and un- manageable. We soon get an insight of their mode of operating. On the outer surface, especially around the gates, small warts or pillars are thrown up, as though to gauge the height of the addition; and between these the infilling is made with pellets of earth, most of which are brought from the interior, where new galleries and rooms are being excavated. The vehicles for this portage are the insects’ Jaws, that serve alike for carriage, as basket or barrow, and for digging, as pick and shovel. The irreg- ular faces of these pellets fit into and fasten upon one ‘See Prof. A. F. W. Schimper’s The Varying Relations Between Plants and Ants, Jena, 1888. 37 ANT COMMUNITIES another, uniting the whole in a way that, perhaps, may not be characterized as “dovetailing” or “ball-and- socket” jointing, but which raises the suggestion of such contrivances. It is said that formic acid, which is extruded freely by ants, forms with silica a natural cement. Can it be that these pellets, which are composed largely of sand, are thus cemented together? Probably not; but at least the moisture of the late rain has aided their adhesion. Grass straws, cut from tufts growing along the base and strewn over the summit of the cone, are dragged into place and skilfully wrought in with the pellets. Besides these, bits of decayed wood, the needle-like leaves of pine-trees, which are abundant here, and leaves of low shrubs are intermixed with the soil. These insect masons are not forced to the hard service laid by the Pharaoh upon ancient Israelites of making bricks without straw. At another hill the builders had undertaken a special work of construction, or, rather, of repair. An errant cow grazing on the mountain-slope—we can hear the tinkle of her bell from a distant corner of the wood— had strolled by that way and set a hoof upon the edge of the mound, leaving a deep and wide impression. Just one; for a swarm of irate insects must have instantly attacked Brindle’s legs and caused her to beat a rapid retreat. But she has left a footprint on the cone that must needs be repaired. As a full day’s work is before us, let us bring camp-stool, note-book, and drawing-pad, and sit down before it. We shall see something that looks like a well-planned system of engineering in filling up the hole. The cow’s foot had made a nearly circular pit between eight and nine inches in diameter and depth. At the 38 NESTING ARCHITECTURE unbroken edge of the pit the task of filling up had begun. From the lower points (A) there extended a series of elevations (a, b, c, d), which marked the upper outline of an are. Beyond this, toward the base of the hill, and parallel with it, was a like series (d, e, f), bending around the depression next to and parallel with its Fig. 23—pRELIMINARY ENGINEERING Mound-making ants filling up a break made in a mound by a cow’s foot lower rim. These little pillars were not alike in shape, and it was quite noticeable that their height gradually increased from the unbroken margin of the mound toward the centre, where it was highest. Yet, through- out, their tops conformed to the general surface of the cone, the diminishing depth from centre to edge being met by a corresponding lowering of the columns. From these, and from similar elevations around the rim of the track, as centres of operation, the work of covering-in proceeded with great advantage (Fig. 28). A number of straws were worked into the columns apparently as braces; and in one of the little hollows were piled many shells of cocoons from which antlings had just been 4 39 ANT COMMUNITIES delivered, and which previously had been carried from the hill and dumped among the stones outside. Within three days, so vigorously did the work go on, two-thirds of the track had been filled up. The new work did not connect with the broken parts on the side toward the summit, but a deep trench, or open gallery, was there preserved all the way across. This seemed strange until it was considered that it was needful, or at least convenient, to keep such an opening into the network interior of galleries in order to allow easy entrance to and exit from the works within the track. Could this systematic order of work, with such plain marks of an intelligent plan, and carried forward much after the manner of men, in their like though larger undertakings, have come about by mere chance? it does not seem reasonable to think so. Yet there was no trace in any quarter or in any act of chief-engineer, or local foreman, or gang-boss, or of. any visible or- ganized directing body, or official supervisor, or regulator, or prompter. Every individual had a mind to work, and every one wrought, but unprompted and un- governed save by its own impulse. Here, also, the observer was impressed by the presence of that invisible, secret, mysterious Something—which he has called the Spirit of the Commune—beyond the veil of science and philosophy, which kept all these active sovereign integers in such harmonious co-opera- tion in the execution of a fixed plan, sustained without intermission for half a week. Is analogous action possible among men? And if not, why not? And wherein lies the superiority—if it be superiority—in this respect of ants over men? Everywhere we note examples of this co-operating 40 NESTING ARCHITECTURE instinct of construction. In order to get a view of the interior of an ant city a mound was sawed through the centre with a large cross-cut saw and one-half thrown aside with shovels. This required vigorous and rapid movements to avoid the attack of the myriad of angry insects thus assaulted in their home. This, however, was less formidable, because the calamity was so unique and terrible—like the earthquake shocks which lately wrecked Charleston and San Francisco, Messina and Reggio—that the ants at first seemed stunned, and moved about as though distraught. Such an over- throw was beyond their limited powers to grasp. But they soon rallied, and promptly set themselves to restore their ruined commonwealth. Yet the blaze of passion was hot enough on the part of those who swarmed from the quarters untouched by the shovellers. Fortunately, the heat and fury thereof were soon expended. Let us examine the interior of the mound thus laid bare. The view of the perpendicular face of the half- cone exposed was truly remarkable (Fig. 29). Tubular galleries three-eighths to half an inch wide rose in regular series one above enother, from the base to the domed summit. The cone within was a rough reproduction in soil, and on a gigantic scale, of the celled structure of the combs of bees, wasps, and hornets. Throughout this network of galleries were scattered cavernous rooms, the common lodging-places for the young and other dependents, although the galleries also served this end, as well as being the roadways be- tween all parts of the community. It is an amazing structure for so small a creatureling, and must have re- quired immense labor and pains to rear it. That this huge hill of sandy earth, mixed with and fixed by vege- 4] ANT COMMUNITIES table matter, and perforated from top to bottom and from side to side with numberless tubes, could be made to stand the stress of mountain weather—rains and floods, frosts and snows—was marvellous. The inference Fig. 29--SECTIONAL VIEW OF ANT-MOUNDS seems inevitable that some sort of hardening material must have been used—secreted from the jaws as saliva, or extruded from the stinging organs—at least upon the inner surface of the galleries. But, however done, 42 NESTING ARCHITECTURE the ants had successfully solved their problem of build- ing a stable structure with friable materials, and had wrought it into a true communal home. To further learn their method, let us fix attention upon one point. A small cavity with a bit of projecting clod on the foundation of the removed part, and close to the remaining one, was the centre of active operations. Just above towered the perpendicular face of the half- cone, along which everywhere squads of workers were SE ees eer Fig. 30—-ANT ENGINEERING Covering-in a broken horizontal gallery and repairing a broken vertical one continually thrusting their brown heads out of gallery openings and dropping pellets of soil. They were clear- ing up the inner débris from the broken passageways, and doubtless some of them were calmly carrying forward the improvements begun before the “earth- quake” (Fig. 30). These pellets were taken up by the workers beneath, who for some reason best known to themselves seemed to prefer them to those that lay 43 ANT COMMUNITIES everywhere around them, the crumbled particles of their shattered home. Two galleries running side by side, the upper parts of which had been destroyed, were being covered over. They were directed along the bottom of the cavity for three inches, and then slanted up- ward to connect with the standing half-cone. The work progressed by continuously adding earth- pellets to the outer edges and pressing them into place. As the sides rose they were gradually arched, and the springing of the arch was plainly seen. The curved edges approached in irregular lines, and at various spots the two projecting points drew near and nearer until they almost touched. It was quite exciting now to watch the delicate manipulation of the masons. Here came a worker with a pellet of larger size than usual. She climbed the arch, moving more daintily as the top was reached. Holding on the while with her hind feet, she stretched across the wee chasm and dropped the ball of soil into the breach. The bridge was laid! And now, with surprising rapidity, it widened as the roof of the arch was covered. Until this was done, openings were left through which the ants moved back and forth, and which were closed over as sections of the arch were completed. They were temporary arrange- ments—‘‘manholes,” so to speak—for the convenience of the builders. Through these one could see the ants at work upon the inner surface, smoothing it with their jaws, as a mason would work with his trowel and mortar. The outside of galleries and rooms was left rough, as laid, but the interior was smoothed. Salivary secretions probably gave the additional moisture needed for this. At one point the gallery was widened from 44 NESTING ARCHITECTURE half an inch, the usual diameter, to one and a half inch, as though a store-room or living-room were being formed. Close by, a vertical gallery, one side of which had been torn away, was being repaired by the infilling of the broken side, and this work was done precisely as in the case of the horizontal arches. One was reminded, in all these actions, of the methods of bricklayers at work upon an arched sewer or culvert, or of masons putting up a rubble-stone wall. There were some marked differences—the profound silence of the worker ants and the absence of overseers. The ant is no ‘‘spendthrift of her tongue.” She ‘‘talks to us in silence.” No one is prompted or driven to work; no one needs to be, for here there are no shirks. No regular hours of service are kept, and there are no fixed intervals of rest. Labor goes on all the time; and, view- ed in the mass, there is no cessation, at least at this juncture, by day or night. Hach individual determines for herself the period of work and the time for rest, and so strong is the sense of duty, or the instinct of fidelity, in every ant, that such individual liberty and respon- sibility are not abused, and the public works of the commonwealth are not damaged or delayed. Building operations were not limited, as in the above cases, to the original site of the cone. A fragment half the size of one’s head, which had been shovelled to one side, was a centre of special activity. It had already been made the nucleus of a new mound. Columns, corridors, and halls, corresponding closely with those out- lined upon the under side of the fragment and united therewith, had been erected. In one of these halls was a small collection of dead ants, a token of a custom sometimes observed among these insects to show a sort 45 ANT COMMUNITIES of funereal respect to the dead of their own household (Fig. 31). This was one of the most interesting and puzzling of the activities developed by the cutting-down of the mound. Access to the uninjured part was easy, and it ¢ 7 iy | ii / rs / Fig. 31—MOUND-MAKING ANTS COVERING A DOUBLE GALLERY a, a, a—Double gallery. c, c, c—Chambers. knowing the habits of these Formicans and their wide range of daily venture, it seemed strange that they did not at once, as did so many of their fellows, rally to the reconstruction work on the old foundation. Had they been found huddled impassively underneath the scat- tered fragments, keeping refuge for the nonce and wait- ing results, it would have seemed natural. But this immediate launching upon an apparently fresh enter- prise—turning to housemaking instead of home-repair- ing, so near the gates of the old republic beginning the upbuilding of a new—this mystified a mere human brain. Did the familiar savor and associations of a bare lump of their former home deceive them? Were they so little 46 NESTING ARCHITECTURE impressed by the commune’s partial wrecking as to think that nothing serious had happened? Was this an instinctive act of self-protection, for the present exigency alone, a sort of bivouac and makeshift, like the temporary camps around a despoiled city? Would these adventurers persist, and build up a permanent seat, or soon return to the old quarters? Was this a proof of superior wisdom, the act of keen opportunists quickly adapting themselves to strange conditions, or of faculties far more limited than we have been wont to credit to ants? Was it simply the result of a physical necessity to be doing, an uncontrollable impulse finding vent in action? But here we stand, vainly speculating and philoso- phizing, while the field of observation just before us is alive with busy insects who have much to show us. Let us go back to the practical and objective. We have seen something of the way in which the citizens of an ant community labor in mass on their public buildings and roads. The manner of the individual now requires to be noted. And here comes a worker-minor who will answer our quest. She has strolled along over the irregular surface of the old foundation of her home, feeling with her antenne here and there without any visible purpose. At last she pauses. She seems to be reflecting upon the ruin around her and without apparent emotion. Ah! if we could but command the mediation of some fairy interpreter of her thoughts! But see! Suddenly she leaps upon a pile of earth- crumbs, and, seizing one in her jaws, lays it down at a little distance with a sharp pat. Another and an- other and many others follow, all gathered and placed with amazing activity. The little body, from the tips 47 ANT COMMUNITIES of her ever-moving antennie to the apex of the abdomen, quivers with the intensity of her energy. She reminds one of a small harbor tug, forging ahead, trembling from stem to stern under her great engine as she draws in her wake a huge ship. Only, there is no puffing! All goes on “‘in solemn silence,” like the shining orbs in “the spangled heavens,” as sung in Addison’s paraphrase of the nineteenth Psalm. Will the day ever come when even a remote approach to this noiseless toil shall characterize human communes? To be sure, since men’s work is so largely wrought by the aid of machines, the racket thereof and the audible strain of their motors cannot be wholly subdued. But it is certain that some of our mightiest and most effective machinery does its work with the minimum of friction, and so of noise. Really a mechanical contrivance might be fairly counted valuable in proportion to the silence of its operation. Always force is wasted in noise— physical and mental as well. Silence is a mighty economist of man’s wealthiest powers. Racket is a ruinous waster. Beyond doubt, at least, abatement in large degree of our city noises is not only desirable, but wholly prac- ticable. They are needless. They are wasteful. They are often cruel to the invalid and nerve-worn. They are remainders of a crude stage of development, and an enlightened people should not tolerate them. They are chiefly the products of thoughtlessness, stupidity, penuriousness, unthrift, and a selfish rudeness. Here also our city magnates and lords of industry might go to the ant and consider her ways with profit. CHAPTER III ENGINEERING METHODS IN ANT STRUCTURES FE return to our lone pioneer laborer of the mound- making ants, left, at the close of the last chapter, in the act of beginning a work of repair upon her desolat- ed commune. Her movements will give us an insight= of some emmet methods in this field of engineering construction. One soon begins to see some purpose in her work, for slowly the suggested outline of a gallery takes shape. Meanwhile a second ant has wandered that way. She halts and, with what appears a careless mien, surveys the scene. Then, struck by an impulse that probably is as mysterious in its origin to her as to her observer, she joins the first adventurer in her attack upon the pile of earth-pellets and in their transfer to the growing gallery. By a like process the squad of workers increases from two to four, from four to ten, from ten to fifty or more, until a busy company swarms over the works, which are rapidly taking distinct form as an arched gallery. The pioneer of this enterprise has long ago been lost to sight among her comrades, and one regrets the lack of brush and white paint wherewith he might have marked the black abdomen, and thus have kept track of her. It is certain, however, that the fact of her having been the first citizen and founder of that settlement had given her no claim to authority or superiority of any 49 ANT COMMUNITIES sort. Her fellow-citizens seemed ignorant of the fact, and it is doubtful if she remembered it herself. Such sentimental considerations have no weight in this wholly utilitarian government and society. Perhaps this is she who slips out of the throng, and, ascending a bit of a clod hard by, squats upon her hind legs and begins to preen her downy coating. What to her now is all the busy scene beneath her? Let the emmet world wag on as it will; she must be clean. And so, in peaceful unconsciousness of all and sundry in her sphere of being, she proceeds with the one present purpose of life, and thoroughly cleanses herself in the approved mode, as hereafter will be described. And now, her purifications being finished, she yawns, stretches her limbs, gives her antenne a final brush, and leisurely descends from her perch. A moment she stands as though undecided, then plunges again into the whirl of activity on and around the new works, and soon is indistinguishable from her fellows. In the review of these building operations several reflections arise. Here was a test of the ability of ants to meet a new experience, such as was the destruction of one-half of their republic. Accidents like the breach made by a cow’s foot they had known and remedied, but no such misfortune as then faced them had ever befallen. Yet they met it with admirable spirit and method, and with success. They set themselves at once to the work of reconstruction, not only with vigor but with practical wisdom, and with ready adaptation of means to the new conditions. Their instinct was sufficiently elastic to cover a strange and colossal ad- versity; or, may we infer that the appeal in the emergency was to something other than routine instinct 50 ENGINEERING METHODS —something, in fact, that nearly approached and cer- tainly suggested a process of adapting means to ends, that bore the earmarks of reasoning? Again, their swift and perfect reaction from the first shock and excitement of a disaster that well might have overwhelmed ambition and endeavor was noteworthy. They went straight on with the ordinary duties of life in the uninjured part of their city, and took up the ex- traordinary ones without a sign, understandable by human intelligence, of grief, or passion, or discourage- ment, or deep emotion. No time was wasted in useless moping, no vigor in aimless schemes. At once they aroused themselves to action, and attacked the emer- gency with admirable energy and poise. Among men such self-control has been called the fruit of philosophy. If such it be, will we be able to deny our mound-making ants the title of insect philosopher? Certainly they are apt—are they automatic ?—imitators of the philosopher’s role. And not to a few rare spirits, the sages of the commune, but to all and equally is the honor due. Nature maintains in the ant city Voltaire’s ideal con- dition that a philosopher should live only among philosophers. A curious observation as to how active work may affect the physical condition of ants was made upon three mounds listed for daily special study. For several days they were found in such an unusually excited condition that they were down in my note-book as the “hysterical hills.” The cause of this agitation evaded all inquiry, but the cure was most interesting. Rains that succeeded the first dry days of our coming were observed to have imparted activity in building operations to a number of mounds. The prediction 51 ANT COMMUNITIES was thereupon ventured to one of our company that we should find our “‘hysterical hills” busily building up their cones like their fellows of other mounds, and as a result settled into their normal composure. And so we found it. They were working at the top of their bent, and were subdued in temper and manner. Honest, hearty physical toil had quieted them, as it often does over-nervous human beings; or, perhaps it had filled their natures with a present and pressing duty, thus diverting them from that useless expenditure of force that often comes from purposeless inaction. One must also note the immensity of the labors wrought by the insects. These may seem trivial as one watches them lifting up and placing here a pellet and there a pellet of soil, and building them into the walls of the common structure. But if the results be con- sidered, they will seem astonishing for such small creat- ures to accomplish. Perhaps a comparison with a noted building achievement of our race, the great pyramid of Egypt, may here be allowed. It is true that such com- parisons are apt to be superficial and misleading, but from a purely popular standpoint they are allowable and may be instructive. The cubic contents of one of the largest mounds was calculated to be in round num- bers two million cubic inches. We may estimate the bulk of an ant to be equal to that of a cylinder three- eighths of an inch high and one-sixteenth of an inch in diameter. Taking thirty-five one-hundred-thousandths of a cubic inch as the bulk of a single worker ant, the size of the builder would be to the size of the edifice as one to fifty-eight hundred million. Let us compare this with a corresponding estimate of the work of man, taking his bulk as six cubic feet, and accepting the solid o2 ENGINEERING METHODS contents of the great pyramid as reckoned at seventy- six million cubic feet. We shall have the following formula of comparison: Man’s bulk to his building is as 1 to 125 millions; The ant’s bulk to her building is as 1 to 5800 millions. A simple calculation will show how greatly this ex- hibits the comparative superiority of the insect in the mere quantitative re- sults. It should also be considered that in these and all other such works the ants have no mechanical ap- plianeces such as mul- tiply the effect and ease the fatigue of hu- man labors. Her sole tools are her jaws and feet’ (Figs. 32, 33), the bodily appendages with which nature has provided her, although it must be admitted that these are highly Fig. 32—anrs piaciIne OUT GALLERIES effective. (Drawn from an artificial formicary) There is another c—Claws. d—Particles of dirt. comparison—in sooth p—Point being dug out. his) 2 contrast — which needs here to be drawn. Such knowledge as has come to us of the building methods obtaining in ancient Egypt shows that the laborers were driven to their hard tasks by overseers who urged on gangs of workmen with the lash. Theirs was unwilling service, 53 Fig. 33—-AN AGRICULTURAL ANT’S FOOT, ENLARGED 180 DIAM- ETERS: THE TOOL USED, WITH THE JAWS, IN DIGGING acl—Attached claw. at—lIts articulation with the joint. icl—Inserted claw. 7in—The inserted parts. s r—sSer- rations on same. / m—Foot muscle. pv—Pulvillus or foot pad. ENGINEERING METHODS cruelly exacted. We have already seen that the ants rendered free and willing service, and that their toil was without overseers, and wholly of individual selection. From the beginning to the end there was no discord among them; no protests; no strikes, sympathetic or otherwise; no walking delegates or their insect analogues; no oppressing (or oppressed) contractors or owners. Indeed, there was no occasion for any of these frequent appendages of great modern structures whereon human workingmen—artisans, mechanics, and common laborers —are engaged. And yet the work was done, and on undertakings relatively many times greater, in the most perfect har- mony, good temper and content of all. Is it possible for man to draw some lessons from this example of natural civics? Is it beyond hope that some goodly measure of such results may lie within the sphere of the practicable for our current organized society? Does our ‘‘civilization”’ hopelessly encumber us from ever attaining the ideal commune? Must it lie in the bright cloud-realm of the optimist’s dreams, until—alas! can it ever be%—the whole race, reborn and disenthralled, shall return to the unsullied simplicity of nature? ~ It may be drawing too fine a distinction in the build- ing work of ants to discriminate between architecture and engineering. Yet we seem to note such a distine- tion. The commune of the agricultural ant, already described, is differenced from its fellows by the circular disk (Fig. 34) that surrounds its central gate or en- trance. The construction of this disk, and its main- tenance as a free and open plaza in the midst of the surrounding subtropical foliage, are works for which no little skill and energy are required (Fig. 35). S 55 ANT COMMUNITIES IO aie Cerne 2 } Le ar VA torch Pde fe < 74 CE r : 5 Fig. 34—THE CIRCULAR DISK AND ROADS THAT SURROUND THE ONE CENTRAL GATE OF THE AGRICULTURAL ANT OF TEXAS But this is only the beginning of the enterprise, the pivot upon which more important undertakings centre. At various points around the circumference of the disk enter a series of cleared trails, widest at their point of contact, that radiate into the surrounding herbage, whose denseness at once suggests the reason for their construction. In short, they are roads laid out to penetrate the harvest fields of these granivorous ants, and are used and admirably adapted for that purpose. The method of transportation in use by harvesting and other ants is primitive enough, consisting simply in personal carriage by a host of individuals (Figs. 36, 37, 08). It is the method of the African explorer, the method of primitive man when unable to utilize the beast of burden. But it is effective. It is here that the engineering quality of the roadways comes in; they 56 ENGINEERING METHODS converge upon the entrepot of the colony. They facili- tate transportation by making communication easier and quicker. However they may have arisen in the history of the harvesting habit’s development, or with what pur- pose (if any) originally constructed, the facts are as stated. And they do not stand alone. In the summer of | Fig. 38 Fig. 35 — AGRICULTURAL ANTS CUTTING GRAIN TO CLEAR ROADS AND DISKS Fig. 36—ANT CARRYING A PELLET OF SOIL Fig. 37—-A SPECIMEN OF GRAIN-STALK ON AN ANT CLEARING Fig. 38 —AGRICULTURAL ANT CARRYING GRAIN-STALKS 57 ANT COMMUNITIES 1887, while visiting Scotland, I spent two days at the Trossachs Hotel, which is located in the glen known as the ‘‘Pass of Achray,” through which flows the little Achray river (or creek) which Sir Walter Scott describes as “‘the stream that joins Loch Katrine to Achray.” Here [found a number of nests of Formica rufa, the well- known “horse ant,” or ‘‘wood ant,” of Great Britain. They were built on either side of the footwalk that leads from the Trossachs glen to “the sluices,”’ as they are popularly cailed, which regulate the stage of water in Loch Katrine, the source of supply for the city of Glas- gow. The demands of humanity are imperative; but the lovers of romance cannot but mourn that the spell which Scott’s genius has thrown over such beautiful spots as ‘‘Ellen’s Isle’ and the ‘Silver Strand” is being dissolved before the engineer’s need for greater water-storage capacity. The mounds raised by the rufous ants were found to be cones of earth intermingled with chippage of various sorts. They were about three feet high, and some of them from six to seven feet in diameter across the base. They resembled those of our mound-making ants of the Alleghanies in general appearance, but their builders seemed to make a freer use of leafage and chippage to work up and cover their nests. The surface was quite thickly thatched with bits of straw and leaves, stalks of grass, pieces of fern, and various like materials. Num- bers of openings appeared upon the surface at irregular intervals from the summit to the base, and at 4 P.M. many workers were dragging the chippage back and forth, as though arranging to close the doors for the night. EMcC. 233) pacue These huge cones stand in the midst of the tall 58 ENGINEERING METHODS bracken—a large, coarse fern that overhangs them, and at times almost hides them from passers-by, as a forest might hide a castle standing in its midst. My attention was especially attracted to the character of the roads leading from the ant-hills to various points in the surrounding wood. ‘These were distinctly marked upon the surface of the ground, having in places a width of from two to four inches stained dark brown or black by the formic acid exuded from the insects as they passed along. The fallen leaves and crushed grass upon which the trails were made were pressed down and smoothed by the constant action of innumerable legs upon the surface. So well marked were these trails that they were easily traced even without the presence of the columns of ants that marched back and forth upon them. While following up one of these roads, I was struck by the fact that it showed scarcely any deviation from a straight line. In order to test this matter more care- fully, I selected a large mound from which three roads radiated. These were all traced to their termination at three several oak-trees, up which the columns of ants ascended to obtain the honey-dew supplied by numerous aphides that infested the branches. The roads were carefully marked out by stakes set at short intervals, a plan made necessary by the high bracken, whose stalks stood so closely together that they had to be pushed aside to trace the roads. The following facts resulted: Road No. 1 was sixty- five feet in an almost perfectly straight line from the nest to the tree. Road No. 2 was seventy feet long and varied less than three inches from a direct line drawn from the nest to a point within two feet of the terminal 09 ANT COMMUNITIES tree. There the column made a détour of about six inches. But an abandoned path continuous with the main road, which apparently had been used at a recent date, was traced for a considerable distance farther. Road No. 3 was the longest, being more than a hun- dred feet long. It extended for nearly twenty feet in a straight line, at which point it touched an old stump that deflected it at a shght angle. Thence it was continued in a nearly direct course as far as a beaten footpath through the wood. Here the ant trail was oblit- erated by passing human feet, although the ants still thronged the pathway, there much broadened by the con- tinual interference and loss caused by foot-passengers. The trail, however, was resumed at a point nearly oppo- site that at which it touched the path, and was con- tinued again in a straight line about twenty feet farther to the tree where it ended. When the entire trail (No. 3) was staked off, it was found that its terminus deviated less than three feet from the straight line drawn from the point of departure at the ant-hill. The greater deviation in this case was doubt- less caused by the peculiar difficulties in the track. The three roads so radiated from the parent nest that they were included within about one quadrant of a circle, of which the two shorter trails might represent radial boundaries of the quadrant, while the longer trail was midway between the two. Looking simply at the results of these observations, it is manifest that these rufous ants showed an accurate sense of direction in marking out and following their approaches to the trees. It would not be reasonable to attribute such mathematical accuracy as above shown to mere accident. The roads in point of directness were 60 ENGINEERING METHODS as well laid out as are works of a corresponding nature done by the engineering skill of men. And these are not isolated cases, but mark the general rule. The mound-making ants (Mormica exsectoides) of America, which so closely resemble Formica rufa in their archi- tecture and general habits, show like characteristics in their road-making, though I do not remember to have seen it displayed under such difficulties. The question inevitably arises, How did the ants _ manage to lay out these roads with such precision? When a corps of engineers or road-builders produce like results, we easily call up certain steps that have been taken. We think of two or more persons, provided with surveying instruments, all dominated by the sense of sight, and controlled by reasoning upon the facts and figures entering into the problem, making out certain lines, and, as far as conditions allow, laying out the course in a_ straight line between the points to be connected. In the case of the ants we start under the embarrass- ment of not having the facts to reason from. Were the roads*marked out at once, or are they a gradual gvrowth? Wedo not know. Has the direct course been determined by a great number of experiences, of which the errors in direction were gradually eliminated, and the final result—viz., the shortest path to the desired point—retained? We do not know. It is easy enough to understand how, after a course has once been fixed, the ants follow it unhesitatingly. Their antennze, which are continually waved before them and to every side, at once detect the strong odor of formic acid on the trail. This is a perfectly accurate guide, and beyond doubt it is thus that the workers pass 61 ANT COMMUNITIES so swiftly and surely between points on the established route. The sense of sight, it will be observed by the reader, is not here considered. It is probably a_ negligible factor, or at least does not appear to play a considerable part in determining results. The visual organs of ants are good as far as appearances show, and as compared with those of the winged hymenoptera, as bees and wasps, ought to contribute something effective toward a visual memory of the localities over which their owners operate. They may do so here. But myrmecologists seem at one in the opinion that the vision of ants is extremely limited; and if so, it could hardly have ef- fectively directed them in laying out trails of such length as here considered. Moreover, the great ferns referred to as closely en- closing and overhanging the ant-hills and the whole surrounding region would probably have hindered the effective exercise of vision, unless we suppose that the course of the trails was fixed in the early spring before vegetation began and the vicinage was quite open. Suppose we indulge in a bit of speculation? Let us imagine that when the winter has so far broken as to allow the insects full liberty of out-door life, a group of workers start out from the parent commune to explore the neighborhood for food. After the fashion of their kind, we see them passing to and fro in zigzag lines, in arcs and parabola. They are thus storing their mem- ories with impressions by which to localize their route and insure their return. Farther and farther, and by gradual recessions, they reach an oak-tree. To ascend it is a part of the natural inquisitiveness (and acquisitive- 62 ENGINEERING METHODS ness) which so strongly marks these insects, and forms an important factor in the feeding of the commune. A tree is a veritable bonanza for insects of various sorts at sundry seasons. The sappy exudations of the plant; the opening buds; the bleeding galls; the hosts of insects, as coccids and aphids, that infest various parts, and prey so freely upon its generous bulk that their superabundance yields a rich harvest for many other insects—one or more of these may attract our foraging scouts. And now, full laden, they are ready for the return journey. Their path down the tree is easily traced by their ascending trail. The real difficulty must arise as they reach the ground and face the home commune. Yonder it lies; the general direction is not hard (for us) to determine. But amid all these involved crossings and reecrossings, of their first outgoing trail, how shall. they find a straight path home? The author is loath to resort to the supposition of some occult power, although he believes in a divine Over- force as the one intelligent source of all creatures and all their actions. His own explanation (held without positiveness) is that, by means of the odors left during their approach and recognized by the sensitive antenne, assisted, perhaps, in some degree, by visual impressions, the ants discern the general course of their trail. It may be also that a spirit of venture which possesses most living things, and a profiting by happy chances which befall, may aid in giving them the first bent homeward. Moreover (and I am inclined to emphasize this point), the home commune, as the central abode and scene of activity of a vast multitude of ants, must be a huge reservoir of formic fumes that strongly impregnate the 63 ANT COMMUNITIES surrounding locality, and serve as a sense-signal that affects, even at a distance, the sensitive antenne of the workers, and so points the direct way home. Thus it falls out that the return is apt to be far more direct than the outgoing. The next outgoing naturally would be over a some- what more direct trail than even their first return, and so, in the course of a few trips, the first indirections would be eliminated, and the trail established in its lines as when I saw it. Something like this, perhaps, may be a natural history of the method by which the ants perform what seem to us notable engineering feats in laying out their roads. But there are cases which cannot be explained so satisfactorily. While studying the cutting ants of Texas, near Austin, I took occasion to follow up the underground routes of some of this species. A planter, in order to get rid of the depredations of an immense commune near his residence, had set his men to dig it up and utterly root it out. In order to reach the central nest he had traced the ants from a tree inside his home premises, which they had stripped of leaves, to a point six hundred and sixty-nine feet distant. The nest occupied a space as large as a small cellar, the lowest and main cave being as large as a flour-barrel. in this central cavern were great numbers of winged males and females, and innumerable larvee and workers. From this point radiated the various avenues over which the leaf-cutters marched on their raids. With the aid of a young civil engineer, I proceeded to survey the main course of the insects. For part of the way we had but to follow the diggings of the planter’s laborers. For the rest, it was only necessary to sink 64 ENGINEERING METHODS holes here and there along the estimated course to the main nest, and, when the tunnel was struck, take an- other bearing. These bearings were afterward handed to a friend,! who had them translated into a chart. In some places the tunnel was as deep as six feet beneath the surface, the average depth being about eighteen inches. At the ‘exit hole,’ four hundred and eighty- four feet from the nest, the tunnel was two feet deep. Besides this main way there were two branch tunnels, which deflected from the trunk-line near the country road, in order to gain entrance to a peach orchard one hundred and twenty feet distant. This chart shows better than any verbal description the problem in underground road-making which the cutting ants faced and effectually solved. [McC. 6, p. 224.] It quite confirms their ability, at least, to achieve such an undertaking as described by Dr. Gideon Lin- cecum, who observed a raid made by a colony of cutting ants upon a garden situated on the bank of a creek that flowed between their nest and the garden. In order to reach the desired plants they drove a tunnel beneath the bed of the stream, and, ascending on the opposite shore, successfully raided the garden. [Li., p. 327.] Gen. S. W. Fountain, of Devon, Pennsylvania, a re- tired officer of the United States army, recently (1909) related to me an incident that quite confirms Lincecum’s statement. While stationed at Fort Clark, Texas, during the summer of 1879, with Troop “E,” U.S. Cavalry, the troop garden, whose conduct was assigned to Captain (now Colonel) A. B. Kauffman, was so persistently raided by cutting ants, who stripped the vegetables of their 1The late Mr. Strickland Kneass, C.E., Assistant to the Presi- dent of the Pennsylvania Railroad. 63 ANT COMMUNITIES leaves, that the site had to be abandoned. It was transferred to a spot near by that was surrounded by an irrigating ditch, and, thus insulated, was supposed to be quite safe from emmet assault. But in course of time the cutting ants appeared within the island gar- den. The officers, supposing them to be the former troublesome community, concluded that they had en- tered by tunnelling beneath the stream. What other way? But Captain Kauffman, sceptical of their ability to accomplish such an engineering feat, resolved to in- vestigate. He drained the irrigating stream (some four or five feet wide), dug up the bed, and traced the in- sects’ trail from their point of entering the garden to the old nest on the opposite side. The ants had in- deed tunnelled beneath the water, guided unerringly by their remarkable instinct in engineering. I have no explanation to offer of the method by which the Attidze accomplished these feats in subway en- gineering. The facts are given, and they are without question. But by what peculiar topographical sense or gift, or by what faculty or process they carried out schemes which compare favorably, relative powers and proportions considered, with underground roads- and tunnels of our own species, this author con- fesses his inability even to suggest an explanation. One may see how upon surface trails the antennze aid in fixing the direction of the ants’ course. But it is not possible to see how they could aid in laying out tunnels underground. We turn to another and widely different use of the engineering faculty. In earlier days the gates of great buildings and of walled towns were kept with a high degree of diligence and ceremony. This was warranted 66 ENGINEERING METHODS by their relative importance in the military methods of the period. It has now wellnigh ceased, except as a quaint survival of medizeval ways in castle and town, or as a relic of military days and discipline. It is in- teresting to find among the communal habits of some species of ants a like marked attention to opening and closing the public gates. And this is not a mere survival Fig. 39—OccIDENT ANTS: SINGLE AND DOUBLE GATES OPEN of a habit out of which the soul has gone, but is kept up seriously as an important part of the communal de- fences. Though the writer confesses that more than once he has found himself questioning its utility; which probably means his inability to perceive the same. Among the communities most persistent in keeping up this habit’ are those of the oecident ants, and examples of the custom as it obtains among them, and in one other species, will sufficiently illustrate the author’s observations. In form the gates of Oeccidentalis are funnel-shaped openings through the gravel roof of the central mound into the interior, at an inclination of about forty-five degrees. There is usually but one gate, located about one-third of the way from the base. It is single or double, according as it opens into one gallery or two, the former being about three-fourths of an inch wide, the latter from one and a half to three inches (Fig. 39). Within, the terminating galleries are quite smooth; q 67 ANT COMMUNITIES without, they present the appearance of a rude stone wall in miniature. Around these gates gathers the daily out-door life of the ants. Back and forth through them citizens of the commonwealth are continually moving during the working hours of the day. My observations throughout the latter part of July showed that the gates are ordinarily opened near or shortly after 8 A.M., but full activity of the colony did not begin until toward 9 o'clock. The general statement is warrant- ed that the gates are opened between 8 and 9 o'clock A.M. This is not an early hour to go on duty for in- sects that have such a high reputation for industry. However, one must remember WPA E DP, IF | We) p Zp Lp. that the interior work pa [7 ey F whe MY (Gs ew } of a formicary, which is very great, may be still going on behind closed doors. Moreover, I found that in a special exig- ency—as injury to a mound by floods—the ants modify their habit, and are found hard at out-door work at early hours. The manner of opening a gate cannot be fully de- scribed, because the work is done chiefly within and behind the outer door of gravel. Doubtless the mode 68 Fig. 40—occIDENT ANTS CLOSING GATES ENGINEERING METHODS would be shown correctly by reversing the process of closing gates (Fig. 40), presently to be described. What one first sees is a pair of quivering antennz above one of the pebbles, followed quickly by a brown head, and feet thrust through the interstices of the contingent gravel- stones. Then forth issues a single worker, who peeps to this side and that, and after compassing a little circuit round about the gate, or perhaps without further ceremony seizes a pebble, bears it off, deposits it a few inches from the gate, and returns to repeat the task. She is followed, sometimes continuously, sometimes at intervals of ten, twenty, even thirty minutes, by a few other ants, who aid in clearing away the barricade. After that, the general exit occurs. On other occasions the method is not so deliberate, or at least it does not appear so. There is a rush of workers almost immediately after the first break, who usually spread over the cone, bustle around the gate, gradually widening the circles, and finally push out into the sur- rounding herbage. At first the exit hole is the size of a pea, and plainly shows that sand and soil have been used under the gravel to seal up the gate. The process of closing gates is even more interesting to the observer than the opening, as the various steps are more under his notice. It will best appear by trans- ferring from my notes a few records: About 6 this evening (July 19th) the closing of doors began. At nest A the work was chiefly from within. The workers pushed the sand from the inside outward with their heads. A grass straw about an inch long was brought from the interior and pushed out until it lay across the gate as a stay for the infilling material. Soil was here 69 ANT COMMUNITIES used principally for closing, a few pebbles being added. The gate was not filled up quite flush with the surface of the mound. At nest B, which had a double gate, two workers-minor were the last and chief operators. They brought gravel from near-by parts of the cone and filled in the two openings flush with the surface. At nest C, with a single gate, a worker-major was operating as at B. A number of ants had been en- gaged at first filling and gradually closing the inside, but all had retired within except one mayor. When the gate was nearly sealed a straggling minor came out of the grassy commons and essayed entrance. Several trials and failures followed, whereupon she commenced dragging dirt from the opening. While thus occupied the major came up with a huge bit of gravel, which she dropped upon her comrade with as much nonchalance as though she were one of the adjoining pebbles. At last the minor dug out a tiny hole through which she squeezed into the nest, and the major, who was again deliberately approaching close behind, carrying another pebble, straightway sealed up the opening. During this amusing episode the straggler did not try to aid the closer, being wholly bent on entering, and the gate-closer paid her no atten- tion beyond the first satisfactory antennal challenge. Each moved forward to her own duty with the undis- turbed placidity of a machine. At nest E by 6.30 p.m. most of the commune had entered the cone; at 6.45 the gate was being closed; at 6.55 only two ants were outside, slowly working at the gate, then half shut. An ant came out with a bit of straw, carried it to the refuse-heap, and returned. At 6.58 two ants came with chopped leaves, and at 7 P.M. 70 ENGINEERING METHODS yet another. None of these attempted to help the gate- closers, who slowly and steadily filled up the entrance. Now occurred the usual side-play with late-comers. At 7.07 a straggler came along and tried to get in. As the gate was nearly closed, she deliberately proceeded to break it open. A pebble was taken from the gate- covering and carried three inches up the mound. An- other was tugged still farther up, and yet another. Then in steps the gate-closer, quite undisturbed by the counter-working of her fellow, and quietly plugs up the little break made with a big pebble, and slips within at a by-cranny that had escaped the straggler’s notice. A second straggler appears while the closers are ad- justing the material from within, as may be seen by the agitation of the surface. Meanwhile the first straggler has grappled with the last big pellet dumped, which she succeeds in dragging aside—of which straggler number two takes advantage, and steps into the nest. There- upon one of the closers reappears from the inside, and, without the least token of vexation at thwarted plans, restores the piece to its place and returns. Straightway the first straggler renews her opposition effort, and has just set the pebble aside when a small black beetle comes up. This the straggler seizes, puts down, turns, reseizes, and tries to push into the gate therewith. The beetle, however, escapes; and the for- aging instinct which led the straggler to forego for the nonce her house - breaking is not strong enough now to divert her from the home trail. So beetle goes her way unpursued and the contrarious straggler disappears inside. At 7.20 a gate-closer comes out and adjusts several pebbles. My imperfect perceptions cannot discern the 6 71 ANT COMMUNITIES advantage thereof, but doubtless the ant quite under- stands. The other closer is seen reaching up and ad- justing pellets from within. At 7.21 the outside closer goes in at the small opening between the top of the gate and the inlying gravel. At 7.27 I still see, by the mo- tion of the pellets of soil and agitation of the pebbles and occasional glimpse of the tips of antenne and mandibles, that the final sealing-up of the communal walls is being accomplished within. In a moment all is quiet, and the gate of the emmet city is shut for the night. Externally it now seems to be a simple semi- circular or triangular depression in the gravel armor of the mound. The other illustration of the gate-closing habit among ants is drawn from the cutting ants (Alta fervens) of Texas, observed in 1877. [McC. 10, pp. 33-40.] One immense commune was assembled around the trunk of a live-oak tree (Quercus virens) on a road-side. The ex- cavations from the interior had gathered into a mound twenty-one feet long and about four feet high. This accumulation, called by the natives a “‘bed,”’ was evi- dently one of many years’ standing, and when sub- sequently opened was found to be inhabited by legions of ants from the size of a bumblebee to that of a small garden ant. It seemed incredible that such hosts of living creatures could dwell within such a narrow com- pass and all find nourishment. And to think that they live on mushroom gardening!—as we shall pres- ently see. My first view of the mound was a disappointment. It was in broad daylight, and not a sign of life appeared. Could it be an abandoned nest? Having satisfied my- self that the mound was inhabited, I arranged for an 72 ENGINEERING METHODS evening visit. Here and there were scattered over the surface small, irregular heaps of dry leaves, bits of leaves, chips, and broken twigs, which seemed mere accidental drifts and piles (Fig. 41). Returning about nightfall, I found the scene wholly changed. Hosts of ants of various sizes were already Fig. 41—a CLOSED GATE OF CUTTING ANTS OF TEXAS hurrying out of open gates into the neighboring jungle, and two long double columns were stretched from the bottom to the top of the overhanging tree. The ants in the descending columns carried above their heads portions of green leaves that waved to and fro, and glanced in our lanterns’ light, giving them a weird seeming’as they moved along. It is this habit that has given the insect the popular name of “‘parasol ant.’’ I first directed special attention to the opening and closing of the gates, which occurs before and after every exit. The opening began about dusk. First appeared from beneath the heaps of dry leaves and chippage scattered irregularly over the surface a number of minims, very tiny fellows indeed. They carried from within small grains of soil. Perhaps an interior cave may have been used as a dumping receptacle for the earth-pellets and smaller rubbish. This was a tedious process, and little seemed to be accomplished until this 73 ANT COMMUNITIES squad was joined by larger forms, who began to carry away bits of chippage. This was also a slow process, but it seemed to avail in gradually loosening up the massy material crowded into the gate; for now came a grand rush from within, the workers, major and minor, and the big-headed soldiers in the lead. They broke forth, bearing before them the larger bits of gate-closing rubbish, which was scattered here and there, and in a few moments was cleared away from the gallery and strewed around the margin of the gate (Fig. 42). This chippage appears to be a part of the communal treasure, for it was easy to identify a number of the pieces as having been used several days in succession. The ants having found out just what shapes and sizes Fig. 42—cUTTING ANTS: A GATE WIDE OPEN were best adapted for effective infilling, were wise enough to keep them close by and use them again and again. The closing of gates began early in the morning and dragged along until ten o’clock. The galleries, of which the gates were the terminals, sloped from the surface, at as great an angle as forty-five degrees, a conformation 74 ENGINEERING METHODS that favored the process of closing, as it gave purchase to the material. In shutting the doors of the commune, the minors appear to begin work by dragging the dispersed chippage toward the gate. One after another they were taken in, and lodged and adjusted. It was certainly not a mere Fig. 43—-CUTTING ANTS: A GATE IN PROCESS OF CLOSING anthropomorphic fancy that in this process the work- ers showed admirable ingenuity and a rude but effect- ive sort of mechanical skill (Fig. 43). For example, the longest stalks and leaves were stretched across and wedged into the opening and vestibule so as to form a rough scaffolding upon which the shorter pieces could rest. As the gate gradually filled up, smaller castes of workers appeared upon the field, and took up the work to which their slighter frames are adapted. The last touches were carefully and delicately made by the minims, who in small squads fill in the interstices with small pellets of soil. Finally, the last laborer steals in Tx ANT COMMUNITIES behind some bit of leaf, and the gate is closed. The . infilling material occupies the opening to a distance of (sometimes) an inch and a half within the gallery. The exterior of the gate now presents the appearance already described of a small heap of dry chippage accidentally accumulated upon the surface. CHAPTER IV SUPPLYING THE COMMUNAL RATIONS OR all living creatures food is a first demand of nature. The struggle to obtain it in the vegetable and animal kingdoms keeps the wheels of life in active motion; and day and night, secretly and openly, silently and with sound and stir of mighty conflict, it goes on among and around all beings. Its influence in shaping life and habit is constant and incalculably great. In- deed, in many, perhaps in most cases, it is decisive—at least in certain epochs of the individual and communal eareer. Thus, a study of the food supply of ants is of highest importance in determining their natural history. As a general rule, covering most of our common ants, the founder of the future commune is a single fertilized female. After the marriage flight she seeks in the vici- nage of her alightment a suitable site in the ground or in wood, according to her instinct. Therein she pre- pares a brooding-cell, which is commonly forced into an oval shape by her rotary movements in forming the wall that shuts her in. This cell becomes the tomb of the great majority of females, but a few survive to be the founders of communes. The eggs laid by the queen are tended and the young are fed by her during her isolation, which may last three - quarters of a year. As she never leaves her hermitage, whence comes her food supply? Naturé has Lae A 7 ANT COMMUNITIES provided a store in the voluminous body, generously nurtured during her virginity by the laborious and self- denying workers of her home nest, who thus uncon- sciously had wrought out a further part in preserving their species. This stored-up substance, together with the degenerating wing muscles, is transmuted into food, which passes as a salivary secretion from the mother’s mouth to the mouths of her progeny. In many cases this supply is supplemented by her own eggs, a con- siderable percentage of which she eats. The first individuals matured are naturally scantily nourished, and for this reason, perhaps, appear as minims, or ants of the smallest caste. At all events, the firstlings are minims, and their smaller demand for food well accords with an empty larder. The known ability of worker ants to endure a long fast is shared to some extent by these callows. But as their philopro- genitive instinct at once awakes, and prompts them to feed and care for the larval dependents in the cell, the supply of rations is a pressing problem. Before the double demand of hunger and devotion to the commune, their primitive cell walls melt away, and the young ants break forth into a new world. What a great, strange world it must seem, even to their imperfect perceptions! Doubtless the first circles of adventure which these ploneers permit themselves have a short radius. That will be measured by their initial success in foraging; and that, in turn, will depend upon the site whereon it has been their hap to fall. In any case, their foraging journeys will sweep over an enlarging space, as the demands of their growing commune increase and their experience expands. To a limited human vision the supply of available 78 SUPPLYING THE COMMUNAL RATIONS edibles seems small. But to the omnivorous appetite of ants it is, under favorable conditions, practically in- exhaustible. Ants have proverbially ‘“‘a sweet tooth.” In the vegetable kingdom, nature’s vast fecundity of flowers and blossoms and sappy sweets, so far beyond what seems required for continuing the species, may seem a great waste. But to the insect world it presents a bountiful harvest. One sees them, of all the orders, winged and unwinged, as larvee, as nymphs, as imagines, in countless hordes drawing upon this exhaustless store. Among these insects, ants are everywhere most prominent ; on the low-growing plants, close to mother earth, high up on the lofty trees, and in all grades be- tween they peek and mouse. In companies, in bands, in ones and twos, their busy inquisition is pushed, and their restless antennz wave and tremble. They dip into the flower-cups, and drink of the nectar there. They scout over leaves. They exploit the trunks and boughs. They are everywhere in Flora’s beautiful domain, lapping her sweets, filling their crops with her treasures, growing rich from her redundancy, not for themselves alone, but for the helpless dependents of their communes. They jostle their winged kindred, the bees, the wasps, the hornets, the yellow-jackets, who come by the shorter aerial ways, but are fewer than the persistent and ubiquitous ants, who plod and climb by the roundabout routes which apterous beings must take. There is enough for all; and although I have seen thou- sands of these various forms feeding cheek by jowl upon some rare harvest feast of bountiful Flora’s spreading, I¢ recall no scenes of violence arising from the casual con- tact. Let the reader give no credit for this to the peace- ful temper of the insects. Simply, it is hard to quarrel 79 ANT COMMUNITIES when the crop is full, and when all may have who will all that they may will to have (Fig. 44). It is pleasant to contemplate this phase of the latent helpfulness that lies in creation, and to see the inanimate world, the fields and forests, extending to the hosts of the Insecta so magnificent a hospitality. It is ill repaid, nk i Fig. 44—GuUSTATORY ORGANS OF THE HONEY-ANT (Face viewed from beneath) nk—Neck. fm—Foramen. lbh—Labium. mz—Maxilla. mx. p—Max- illary palp. mb—Mandible. to—Tongue. [b. p—Labial palp SO SUPPLYING THE COMMUNAL RATIONS no doubt, at times—especially by the hordes that prey upon our gardens, orchards, and fields, and compel a ceaseless vigilance to save our crops. But, on the other hand, it is gratifying to reflect that Flora’s bounty to ants and their insect allies is repaid by a service which preserves her domain by perpetuating the life of plants; for the insects that pass from flower to flower and plunge into the cups, distribute the fertilizing pollen upon which fruitfulness and life depend. This symbiosis between plants and insects is thus a necessary condition for both; and that it has existed from the beginning, a study of fossil insects shows. The above seems, as indeed it is, a vast field where- from to cull a living. But one, perhaps as wide and even more lasting, is open in the waste products of nature. Ants are universal scavengers. They are fond of animal oils and juices. Countless millions of insects perish every season. What becomes of them? They drop by the waysides of their lives, and drift into all manner of crannies and corners. Hereto the ants follow them. The searching power of the antenne is something mar- vellous. It has been compared to that of men’s hands were the sense of smell to be located in the tips of all their fingers also, where such a delicate sense of touch abides. What human hands could do, in such a sup- posed case, to follow up and search out odors, the movable organs of smell, the antenne, do actually accomplish for ants. Thus are revealed to them the carcasses of the innumer- able hosts of fallen insects; and often they may be seen headed for their homes, dragging with them whole bodies or parts thereof, and making painful headway therewith through the jungle of grasses and weeds. Sl ANT COMMUNITIES Commonly, however, they are successful, when not way- laid and robbed by stronger individuals, or by roving bands of alien species, or congeners of other communes. The fondness of ants for animal fats and juices may be tested by placing a fresh bone on the lawn or in a field. It will be covered soon with a crowd of emmets greedily lapping the oily particles upon the surface and exuding from the pores. Some housekeepers avail themselves of this appetite to collect groups of the little red ants (Monomorium pharaonis) that infest houses. These being destroyed, the “‘trap”’ is set again and again. Another source of food supply is the various fruits in season, wild and cultivated. The windfalls lying be- neath the trees and bushes are usually bruised, or stung by insects. Around and into these broken parts the ants gather and feast. They climb to the laden boughs. They scout among the ripening fruits. They have a quick touch for a spot of decay, which has opened a way for their gustatory attack. Or a bird’s bill has been before them, cutting a little trough from which to sip the sweets they love, and herein one will see a bunch of ants scooping out the pulps and drinking their fill of the fermenting sap. When September’s sun has mellowed the grapes, you may see legions of ants, joint pilferers with birds and bees, hornets, wasps, yellow-jackets, and flies, many with heads buried deep within the berries. They are lovers of the new wine of the grape, and many empty or partly emptied skins, hanging among the broken clusters like cups drained of their contents, show how often and deeply they and their winged comrades have drunk. Doubtless ants are apt to be a bit injurious to our orchards and vineyards. But their share in the 82 SUPPLYING THE COMMUNAL RATIONS general scavenger work of nature, as well as their part in fertilizing the blossoming plants, may be set to the credit side of their account. Besides, if folk would follow the author’s rule to put in one root-stock for the birds and insects for every two set out for himself, there would be enough and to spare for all. Preying upon insect remains and animal oils, lapping the nectar of flowers and the sweets of fruit, by no means exhaust the sources from which foraging ants may draw their rations. They are free-lances, and they do not secruple to ply their freebooting against all and sundry whom they are able to better in a quarrel over booty. After the manner of human cannibals, they feed upon their vanquished foes; indeed, the formal raids of slave-making ants are chiefly for food. Many thousands of their victims are carried home and eaten. The tender larvee and pupe are kept in store for the slaughter as human butchers keep live-stock and fowl, though one cannot aver that the ants deliberately fatten them for that purpose. Some captives, and at times a number, escape the shambles and become auxiliaries or slaves. But large: communes of these kidnappers have been known to end an active season of slave-catching with but few if any increase in the number of slaves. All their captives had been eaten! The same methods are quite commonly carried out on a smaller scale among various species. I have turned up a flat stone, beneath which was a large nest of small ants. Their larvee, still smaller than themselves, lay in heaps against the under surface. Scarcely had the stone been lifted ere several larger ants, representing two other separate species, rushed in and began plunder- ing the colony. They evidently had been prowling 83 ANT COMMUNITIES around the confines of the nest, waiting for an oppor- tunity to break through the barriers, or snook into some chance opening by which they could reach their desired prey. And this is a typical incident in ant world. Other insects, both in the larval and imago state, are victims of this passion for hunting live game—as fierce and high as ever fired human devotees of the chase. Who has not seen an unfortunate caterpillar writhing in mortal agony beneath the assaults of a large squad of small ants? In vain the victim struggles to throw off its assailants. Its fate is sealed. Spurred into violent contortions by the smarting thrusts of stings and cuts of mandibles, it flings its tormenters to this side and that. They hold on grimly amid all the thrashings until the quiet of death gradually falls. Then the great carcass is dragged and pushed home by a gang of workers or carried thither piecemeal, a vast addition to the communal larder. While studying the agricultural ants in Texas, I observed, after a summer shower, a great commotion upon a large circular disk of one of the colonies. The rain had beaten down a great number of the winged forms of swarming termites, and upon these the red agriculturals were charging from all parts of the plaza. They seized them in their jaws and ran toward the central gate, out of which a file of their fellows was eagerly streaming, intent upon sharing the rare find of booty. The outgoing and incoming columns met. The gate was soon choked up. The tiny rivulets caused by the rain were setting in the same direction, and presently a mass of excited insects was balled and matted around the gate, pushing and tumbling over one another, and splashing in the water. But the possessors of 84 SUPPLYING THE COMMUNAL RATIONS captives from the fallen swarm held to their prizes amid all the tumult, until the Jam was relieved, and they could get. entrance within their nest. Their under- ground granaries were at the time full of stored ant-rice and other seeds, their provision for winter food; but the eagerness‘ with which they welcomed this chance supply of soft, juicy insect flesh showed that their granivorous habit had not weakened their insectivorous taste. I have seen the mound-making ants of the Alleghanies make raids upon the workers of our northern species of termites (Termes flavipes), capturing and carrying them away withan eagerness that showed what precious morsels their soft, white bodies must be to the Formican appetite. Here we may consider the vast food supply that lies in the product of certain seed- bearing grasses, the garnering and storing of which has led to the popular names of “agricultural,” “farming,” and “harvesting” ants.! The habit is especially developed in the genera Pogonomyrmex and Pheidole, which collect from the ground and from plants certain grain-like- and nut-like Bi Garr At aes ey Fig. 45—AGRICULTURAL ANT FEEDING FROM A HICKORY-NUT KERNEL seeds (Fig. 45). These they carry to their nests, and, after removing the husks, and deporting the latter ‘See the author’s Nature’s Craftsmen, chap. vi. 85 ANT COMMUNITIES from the nests, they store the kernels in large granaries excavated in the ground, where they are kept for food. It has been noticed that these seed-eating ants are marked by the presence of large-headed workers, whose unusual development of the muscles of head and jaws particularly fits them to crack and crush the seeds, so that from the meaty kernels may be rasped or squeezed the edible starchy or oily parts. A remarkable example of the unexpected way in which Nature varies her methods of feeding her children is seen in habits of the Attide, the ‘‘parasol”’ or “‘leaf- cutting” ants. This popular name is due to their manner of sending out expeditions of workers, who cut from the leaves of certain trees and bushes small pieces which they bring into their nest to convert into food. These leaf-cutting excursions are striking sights to the novice, and are not apt to lose their interest even to familiars. The author’s chief studies of Atta fervens' were made in the vicinity of Austin, Texas. [McC. 10, p. 33 sq.] Most of their nests were ‘‘beds”’ (as the natives called them), or spots of denuded surface in the flat Open prairie, eight or nine feet long and of almost equal width. Over this barren space were thrown up twenty or thirty circular, semicircular, and s-shaped elevations of fresh earth pellets. The circular mound- lets were about the size and form of a “ pound-cake’’- pan, or spittoon, the resemblance being emphasized by a round open entrance in the centre. All these had been naturally formed by the gradual accumulation of the 'T have used throughout this, the old and well-known name of this species, although Professor Wheeler has restored the yet older specific name of Buckley, by which it will doubtless be known hereafter. 86 SUPPLYING THE COMMUNAL RATIONS Fig. 46—MOUND NEST OF TEXAS CUTTING ANT UNDER A LIVE-OAK TREE PARTLY DEFOLIATED sandy soil as it was brought out and dumped upon the heap, being massed at the base and gradually sloping to the top. Another of these beds, the one which was especially studied and finally opened, was a large mound at the foot of a live-oak tree (Fig. 46). This had prob- ably been formed by a road or trail that passed with- in several yards of the tree, thus restricting the limits of the gates and throwing the separate moundlets back upon one another. [McC. 6, p. 251.] 7 87 ANT COMMUNITIES At my first visit to this great commune it seemed like an abandoned nest. On the spreading branches of the overshadowing tree and on the defoliated vines at its base were marks of recent raids of the leaf-cutters. But no life was anywhere visible. The surface was covered with earthen knobs or warts of various sizes, and here and there were scattered small irregular heaps of dry leaves and bits of leaves, and twigs. As evening began to fall the scene changed. Hosts of ants of various sizes, in countless numbers, suddenly burst from gates that mysteriously opened for them, and began a hurried march into a near-by jungle. Two large double columns began to ascend the trunk of the live oak. Along their flanks, both going and coming, moved the soldiers, Fig. 47—THE HEAD OF A TEXAS CUTTING ANT Enlarged eight times, to show furrow and spines and cutting jaws marked by their immense heads (Fig. 47). They rare- ly handled the leaves, but seemed to act as scouts or pioneers or attendant guards. 88 SUPPLYING THE COMMUNAL RATIONS In a few moments the two-ranked army had reached the top of the tree,and the work of defoliation began. In order to view the mode closely, small branches broken SS f= eS SAS Ba 7S from the tree were set in the mound near the gates. They were soon cov- ered with ants, and in the lantern light their method could be seen read- ily. It was like that of Megachile, the leaf-cutter bee. [McC. 7, p. 145.] The cutter, seated on the leaf, grasped it with outspread feet, and made an incision at the edge by a scissors-like mo- tion of her sickle-shaped and toothed mandibles. She gradually revolved, cutting as she moved, her mandibles thus describing a circle or a portion thereof. The feet turned with the head. The cut was a clean one, quite through the leaf. The Fig. 48—a PROCESSION OF TEXAS ANTS CARRYING LEAVES TO THEIR CAVES 89 ANT COMMUNITIES cutter would sometimes drop with the excision to the ground; sometimes it let the section fall; sometimes carried it down. At the foot of the tree lay a pile of cut leaves, to which clippings were being added continually by droppings from above. Squads of carriers from the nest took these up and bore them away (Fig. 48). This is the manner of loading the cuttings: They are seized by the curved mandibles; the head is elevated; the piece is thrown back by a quick motion, and lodged on its edge within a deep furrow that runs along the entire median line of the face, except the clypeus, and is sup- ported between prominent spines on the border of this furrow and on the prothorax. These peculiar features of the Attidz thus serve a useful end. As far as noted, the cutting and carrying were not done by the minims or smallest castes, but by the worker-minors; the soldiers rarely engaged therein. As the ants moved along down the branches and trunk of the tree, and over the ground to their gates, holding above their heads the bits of green leaves, which waved to and fro and glanced in the lantern hight, the column had a weird seeming. The citizens of this commune, and of some others ob- served, made their leaf-cutting sallies in the night. But this is not the universal habit. I afterward saw carriers marching with their loads during the day. I also observed them frequently in day marches in the vicinity of Santiago de Cuba, during the Spanish-Amer- ican war, carrying on their quaint industry among the graves of fallen American soldiers and in the tropical trees that sheltered them. They were abundant on the great terraced height of the Morro, or castle, at the mouth of Santiago Bay, which I visited just after the surrender, and before it 90 SUPPLYING THE COMMUNAL RATIONS was occupied by the American troops. When ascending the path that zigzags around the cliff to the summit, a column of these insects was seen marching with their bits of cut-off leaves. On the summit, workers were found close by the dismantled eastern battery. Their fresh-made tumuli were cast up almost beneath the butt of the great guns. The workers were thronging into the central gates, bearing aloft their leafy banners. One could not but wonder: Were these industrious creatures plying their task while Spanish cannons were firing and shells from American ships were bursting around them? No doubt they did so—a type of the army of in- dustry in the insect world prosecuting the humble arts of peace amid the roar of human battle and the clash of arms. If their wee brains could be deemed capable of thinking on such matters, we may fancy their thoughts taking shape in the familiar words: ‘“‘What fools these mortals be!’—maiming and killing one another when they might be comfortably cutting Juicy leaves and chewing them into pulp! At an afternoon visit to the grounds of a nurseryman and gardener near Austin, Texas, the leaf-cutters were seen at work. They had come up through the garden from their colony, three hundred feet distant. From this gentleman it was learned that these ants prefer trees with a smooth leaf; are severe upon grapes, peaches, and the china-tree. They take radishes, celery, beets, young corn, and wheat, plum, pomegranate, honey- suckle, cape Jessamine, crape myrtle, and althea. They do not like lettuce, nor the paper mulberry, nor figs, nor cedar, except the bud ends in the scant days of winter. They love sugar, grain, and tobacco. This proprieter assured me that the ants made foraging excursions into 91 ANT COMMUNITIES his house, entered his desk drawers, and carried away a portion of his chewing-tobacco before he discovered the robbery. He had to be careful thereafter where he put the delectable weed. At a plantation not far from this nursery I saw an immense column of Attas plundering a granary of wheat, which was being carried away in quantities, grain by grain. This pilfering was also carried on in the daytime. I have no explanation to give of this remarkable difference in habit in the same species, in the same locality, and apparently under the same conditions. Can Atta fervens have entered upon a transition period in its history? How do the cutting ants dispose of all this material so laboriously imported into their underground city? Is it used, as with the cutting bee, simply to line the chamber or cells in which the young are reared? Let us see. It was no light undertaking to open and ex- plore a mound occupied and defended by hundreds of thousands of irate ants. But it seemed necessary. Two trenches were made, one ten feet long and five feet deep, and a second at right angles to it wide enough to allow free entrance for study. The number of in- sects that swarmed to defend their home was incalculable. It amazed us to see such hordes of creatures domiciled in one commune. They were, however, not so difficult to manage as when disturbed at their night work, as the swift use of the spade by the assailants and the general convulsion of their emmet world seemed to daze them. But when the author entered the trench to work with trowel, knife, foot-rule, and drawing materials, the ants rallied and attacked so freely that all the help- ers were required to brush them off. The wound in- flicted by them was sharp, but nothing to compare 92 SUPPLYING THE COMMUNAL RATIONS in painfulness with the sting of the agricultural ant of Texas. The interior of the great formicary (fifteen feet long, eight or nine feet wide, and four feet high; I do not Fig. 49—cUTTING ANTS 1. Winged female. 2. Male. 3. Soldier. 4. Worker-major of the cutting or mushroom gardening ants. know how deep, but certainly five and probably ten feet) may be briefly described as an irregular arrange- ment of caverns communicating with one another and with the surface by tubular galleries. These caverns, or pockets, were of various sizes, three feet long and less by one foot deep and eight inches high and less. Within these chambers were masses of a light, delicate leaf- 93 ANT COMMUNITIES paper wrought into what may be called ‘‘combs.’”’ Some of the masses were in a single hemisphere, filling the central part of the cave. Others were arranged along the floor in columnar masses two and a half inches high, in contact with one another. Some of these columns hung like a rude honeycomb, or wasp’s nest, from roots that interlaced the cave. No leaves were intact; none used, like the leaf-cutter bee, for lining wall or floor (Fig. 50). In color this material was either of a gray tint or a leaf-brown. It was all evidently composed in great part of the fibre of leaves which had been reduced to this — Fig. 5|0—sEcTIONAL VIEW OF A CUTTING ANTS’ NEST Showing mushroom garden caves in sight. (From nature) form within the nest, doubtless by the joint action of the mandibles and salivary glands. On examination the mass proved to be composed of cells of various sizes, an irregular hexagon in shape, narrowing into a funnel- 94 SUPPLYDNG THE COMMUNAL RATIONS like cylinder. Ants in great number, chiefly of the small castes, were found in these cells. In the first large cave opened there were also great numbers of larve. Large circular openings ran into the heart of the mass. The material was so fragile that it crumbled under even dainty handling, but some specimens were preserved and exhibited in the Philadelphia Academy of Natural Sciences. Thus the query was answered—in part, at least: What do the ants do with the leaf-cuttings carried into their nests? But the most remarkable part of this history remains to be told. While pursuing these investigations, the author knew that the suggestion had been made by Belt that the leaf-paper masses of Atta’s nest were used as a sort of mushroom garden for cultivating a minute fungus which the ants used as food. Examination with a lens showed him the presence of these growths. But as this was only what might be expected in such underground con- ditions, and notwithstanding all that he knew of the ingenuity of ants in providing for the natural wants of their communes, he put aside the theory as improbable, and failed to push experiments which he might have made. His incredulity thus lost him the opportunity to anticipate—in part, at least—some of the brilliant dis- coveries of such later investigators as Moller, Von Ihering, Doctor Goeldi, and Jakob Huber. Briefly summarized, these discoveries are as follows: In the case of Atta sexdens (the Brazilian cutting ant), after her marriage flight the fertilized female begins to dig in some open space a burrow about three-fourths of an inch in diameter. It is at first so small relatively that she cannot turn around in it, but has to back out 95 ANT COMMUNITIES in order to get to the surface. But gradually the burrow grows as the queen cuts off and squeezes together little balls of earth, which are deported beyond the entrance. When the terminal chamber is finished, the tubular entrance is sealed up. Later a little packet of eggs is laid. Beside it appears a small heap of loose white substance which gradually enlarges until it reaches the form of the spherical or elongated masses of gray comb-like matter heretofore described. And now the transparent pyriform globules of fungus-hyphe begin to bud out, which Moller has called ‘‘kohlrabi.’”? On Tig. 51—a PIECE OF LEAF-PULP WHICH FORMS THE MUSHROOM GARDEN (After Moller) these the ant feeds frequently. In truth, this is her fungus garden. It becomes in time the source of her food, just as an artificial mushroom cave or cellar pro- duces nourishment for men (Fig. 51). In time the first workers are hatched, and they too are fed upon the kohlrabi. As they increase in number 96 SUPPLYING THE COMMUNAL RATIONS they break the cavern seals and go forth to gather leaves, which they chew and knead into pulp, and add to the fungus garden. And this is the purpose of those leaf-cutting expeditions which have enlisted the curiosity of casual observers, and excited the ardent and attentive study of many naturalists. They are to supply sub- stance for the fungus gardens from which Attid ants glean food for their young and themselves. Before this strange form of plant culture has reached this advanced stage, however, Huber introduces us to a remarkable observation, in answer to his query: How does the Atta female keep the fungus alive? For, plain- ly, the scant substance in the mother pellet must soon be drained of its original nutriment. How, then, are the growing fungi fed? The queen tears with her mandibles from her little bed a minute bit of the fungus, and applies it to the tip of her gaster, which is bent under for the purpose. She then emits a clear yellowish or brownish droplet, which is at once taken up by the spongy tuft of hyphe. Thereupon it is returned to the garden patch, and patted into place with the forefeet. This per- formance. may be repeated once or twice an hour or oftener, and several of the enriching droplets may be seen at once scattered over the bed. Ifa piece of the fungus growth from a maturer nest be supplied to an Atta female at this stage, she is prompt to appreciate and utilize the gift. She divides it, drenches it with her fecal droplet, and builds it into her garden. Meanwhile the mother feeds largely upon her own eggs, and when the first larvee appear feeds them also with eggs, pressing them directly into the little creatures’ mouths. Soon the first adults begin to appear, which are always minims, or workers of the smallest caste. This intro- 97 ANT COMMUNITIES duces a new order into the commune. They take charge of the garden; they feed the larvee; they feed upon the kohlrabi; they begin to enlarge the central chamber, and in seven weeks after the founding of the colony they are out in the open dumping their earth-pellets upon their circular moundlets, and ere long the colony is send- ing out its leaf-cutting excursions. Thus we see ant communes, under the exigency of the need of food, developing the habit of what has not inaptly been called mushroom gardening. They have mastered the method of liquid manuring, and of inoculat- ing exhausted “soil” with an infected culture. They have learned the value of triturated vegetable matter as furnishing substance and enrichment for their gardens, and apparently they have found out that for this pur- pose certain plants are more valuable than others. If such a principle—or practice—of plant culture were to be as generally and as faithfully applied to gardening and farming among men, it would need no prophet to predict that a new era would dawn upon the agricultural world, and such abundance would follow as our race has never witnessed. Now very naturally arose the inquiry: Whence did the Atta queen obtain the fungus germs with which to stock the original garden? This was solved by Von Ihering in the brilhant discovery that on leaving the parental nest the young queen carries with her in the posterior portion of her oral cavity a very minute pellet of hyphze of Rozites gongylophora, and small fragments of bleached or chlorophylless leaves. This, it is believed, is held in the mouth until she has prepared her foundation cham- ber, when she ejects it, and infects therewith the be- ginning of her fungus garden. 98 SUPPLYING THE COMMUNAL RATIONS Thus the sober and well-attested facts of scientific truth prove stranger than the widest stretch of fancy wouid have dared to invent. Even in the face of un- impeachable testimony, one finds one’s self startled and wellnigh staggering before such a remarkable instinct in an insignificant insect. In the summer of 1880 my attention was called by the Rev. George K. Morris to a small ant which he had discovered at Island Heights, a seaside settlement on Toms River, New Jersey. I recognized it as a species of Atta which I believed to be new, and gave it the specific name of Septentrionalis.' I was so strongly impressed by the appearance of this tropical species so far north that I at once visited Island Heights to study the insect in site. I found that the ants harvested the needle-like leaves of the pine, which were borne into their nests and treated in a way quite like that observed by the Texas Atta, but on a great- ly reduced scale. The nests examined were without an exterior mound. A single gate communicated with a short tubular gallery with a small spherical vestibule, which again opened into a similar but larger cave three inches in diameter. Hanging to the roots that thread- ed this cave were several masses of gray leaf-pulp, the analogues of those in the fungus gardens of Alta fervens. As one contrasted the extensive excavations and the formidable and vigorous communes of the Texas species with the small numbers, slight excavations, and sluggish movements of these Northern allies, he could not for- bear the thought that the New Jersey colonies of Trachymyrmex septentrionalis are the feeble remnant of 1Professor Wheeler has placed it in the genus Trachymyrmex (T. septentrionalis McCook). 99 ANT COMMUNITIES a once mighty people left or thrust by some untoward change upon unfavorable sites which must work toward their extinction. [McC. 15, p. 360.] Or, on the other hand, may we conjecture that here are the first stages in the origin of a new species already on the march, and against unfavorable environment, toward the consum- mation of such a splendid confederacy as has occupied the hills of Austin? CHAPTER V FEEDING THE COMMUNE ONTINUING our studies of the emmet modes of feeding the commune, our thoughts once more re- turn to the great confederacy of mound-making ants among the Alleghany Mountains. We fix our attention upon a column of workers pressing along a well-worn path straight from a large mound to an oak-tree that stands by a boundary stone wall eight rods distant. There the column leaves the ground, mounts the trunk, and is lost among the branches. But here several interesting things are noted. There is a descending as well as an ascending column. More- over, there is something like the sentry service establish- ed at the gates. There is a tree-trail one to three inches wide, to: which the ants steadily keep, and which is blackened by the continuous fumes of formic acid issuing from them. On either side of this are watchmen, who persistently challenge passers-by. There follow swift crossings of antennze and mutual recognitions—how one longs to know the countersign!—prompt withdrawals, and the pilgrims pass on and are soon distributed among the principal limbs. A goodly number lead off upon one of the lower boughs which overhangs the stone fence. Mounting this, one has the key to the movements of the marchers on the avenue beneath. At various points 0) ANT COMMUNITIES along the branches are vast numbers of aphides, small black insects with brownish thorax and head. Note this one, whose abdomen is raised at an angle of forty- five degrees. Upon the apex is shining a tiny globule of transparent liquid. It is lapped up by the attendant ant, who all the while with alternate strokes of antennz gently embraces or pats the insect. Again and again in rapid succession the sweet excretion, pumped by the insect from the sap of the tree, and converted by it into the honey-dew of popular speech, gathers in droplets, and is removed by the ants, several of whom have en- joyed the refection in turn. At last the aphis, one of mature size, leaves its position and moves along the branch toward the trunk. Its ab- domen is now flattened. Many of its fellows have that organ full and rounded out, and must be uncomfortable. The ants, however, are fast relieving them as the sweet excretion flows, and in the mean time their own abdomens are undergoing a noticeable change. They swell and elongate until the folded membranous bands that unite the segments are pushed out into narrow white ribbons. This is caused by the rapidly expanding crop into which the collected sweets are stored. At last the honey-dew gatherer, whom we may now call a “replete,” is satisfied, and turns toward home. It is such as she that compose the descending column of ants upon the tree-trail; and their full, elongated abdomens and white bands form quite a contrast with the round black abdomens of their fellows of the ascending column. We are now on the verge of one of the most interest- ing facts in the history of this remarkable community. These repletes belong to a section of the communal foragers, of whom thousands are elsewhere abroad, not 102 FEEDING THE COMMUNE simply feeding, but collecting food supplies which they are taking home in their mandibles or stored in their capacious crops for the natural dependents and oth- ers of the formicary entitled thereto. Following with closer attention the trail of the repletes, you observe some of them suddenly disappear at the roots of the tree. Turn back the sod, clear away the leaves; what do yousee ? Masses of insects are huddled together in the angles of roots at the foot of the tree and in sundry depressions in the soil. Some are repletes, some are ordinary work- ers; and the latter are stopping or trying to stop the former, who seek to avoid them and to push into certain openings that lead into galleries beneath the surface, which evidently communicate with the central mound. A few succeeu in this, but many yield to the friendly force and halt. And now what? See this replete. She has raised herself upon her two pairs of hind legs until her body slants in a wide angle toward the horizon. And one, two—yes,three workers, assuming a like rampant position, have placed their mouths against the replete’s mouth. Look clesely now, and you will see a droplet of amber or whitish, syrup-like liquid gather upon the delicate, thread-like maxille beneath the replete’s jaw. It is the honey-dew obtained from the aphides upon the oak. It has been forced up from the crop by pressure of the contracting muscular sac that encloses it—in other words, by regurgitation. It is greedily lapped by the three “pensioners,” and the replete breaks away and disap- pears within one of the gallery doors. AI around the foot of the tree are like scenes wrought—visiting ants taking toll of the foragers.’ 1 In connection with these facts, see Nature’s Craftsmen, chap. iil. 8 103 ANT COMMUNITIES Who are these visiting ants? Are they highway robbers? They are certainly not aliens, for the rela- tions of all concerned are most friendly. There is, in- deed, here and there a slight show of force in the deten- tion of a replete who has more than usual reluctance to part with its stored sweets, but there is no element of real hostility therein. Plainly repletes and pensioners are citizens of one community, and their behavior must torm a part of a natural social arrangement. What is it? Not all at once, but gradually, the facts dawned that repletes, acting as communal foragers, were carrying supplies to the formicary; that numbers of their fellows, engaged as builders, sentinels, and nurses, had left their several duties for a little while to feed, and instead of spending time and energy due to the commonwealth in gathering food afield, had come out to tap the garnered stores of their comrades, and, having relieved their hun- ger, would return to their labors. In short, they had been drawing rations from a sort of field commissary department. They are no devotees, these adventurers, of the theory that, ‘““To feed were best at home; But thence, the sauce is ceremony; Meeting were bare without it.” There certainly seemed to be scant ceremony in this method of banqueting abroad. In truth, it had the outward look of levying mail or highway robbery, al- though there was no real violence on the part of those who bade the repletes “‘stand and deliver.” Indeed, upon due reflection, the affair resolved itself into a benefi- cent social function, of which the following appears to be the spirit and intent: The ants at work in or about 104 FEEDING THE COMMUNE the home premises leave the collecting of food to others of their fellow-citizens, not only for the public dependents but for themselves. Content with satisfying the simple wants of nature that they may have strength to toil, they leave their work and visit the feeding-grounds to get food from the repletes. The stations for this pur- pose are wisely chosen; for, as many of the foragers are overladen, their progress homeward is eased by yielding somewhat from their stores. Besides, it seems probable that the instinct which urges repletes to gather supplies for home dependents might, after the formicary had been reached, prevent parting with them to others. Moreover, since ant nature in some degree is partaker of the weakness of human nature, it is supposable that the surplus honey-dew, after feeding dependents, would be kept for individual de- lectation, and the home working-force be compelled to leave their work and forage for themselves. The general movement, therefore, to arrest repletes at stations near the feeding-grounds is evidently for the public good. It would be an odd speculation to consider the effect upon society were such a rule to prevail among men. Suppose the citizens of cities like New York, Phila- delphia, and Chicago, or of such states as Georgia, Ohio, and Massachusetts, were to agree that one moiety of their number should take the duty of earning or collect- ing food supplies of every kind for the entire community, leaving all other duties to the rest? Further, suppose that these gatherings must be divided with equal hand among all sorts and conditions of people—young and old, active and dependent, high and lowly, rich and poor, with sole regard to their real natural needs? Stop! Our phrasing is faulty; for in this ideal state 105 ANT COMMUNITIES of society, if fairly conformed to the type of an ant city, there would be no rank or grade, no rich or poor, no personal distinctions, no individual property. All things would be in common. There would be one and only one property-holder—the State; nor would even the faintest desire for separate possessions ever cross the thought of the most fanciful. There would be no lust for riches or superior place or an easier lot in life. One purpose would dominate all with absolute sway: to serve the All—the whole community—with all one’s powers, in any line of required duty, without hesitation, without stint, without reserve, and without pay. This is truly a wild speculation! This is to conceive of the inconceivable—that human beings could attain the social standards of an ant-hill! One must first suppose a moral revolution which even the dreams of a Golden Age or a Millennium—such as idealists in every century have had—would dimly depict; a revolution more radical than that implied by a literal conformity to the precepts of the Sermon on the Mount and the Saviour’s summary of the moral law. It would be a revolution not only in social characteristics, but in in- dividual character, a veritable palengenesis of every member of the commonwealth. Would it be for the better or the worse? Would our race gain or lose by achieving the communistic - individualistic type of the government of ant cities? It is evident that there must be a good deal of varia- tion in the food supply even under favorable conditions. This would be felt at times when other labors of the commune, as extension and repair of the living quarters, interfere with the regular foraging. Moreover, there 106 FEEDING THE COMMUNE are periods when the reproduction of eggs by the queen is especially active, and the vast increase of larvie, all needing food and care, greatly multiplies the demand both for food and labor. The pinch of such conditions must fall inevitably upon the helpless young. Should they chance to come contemporaneously with a few days of scarcity, which may arise from various causes, the communal dependents must certainly fare ill, and the death-rate be enlarged among them. And it befalls communes of ants, as it comes to nations of men, that great deviations from the ordinary course of nature bring about disasters, at times so great that the very life of the community is at stake. Famine follows in the wake of war and floods, and untimely frosts and droughts consume the sources of food in the world of ants even as of men. The plough turns up the fallow field, and multitudes of ant-nests are destroyed by agriculture. Thus some of our noblest species of native ants are vanishing before the advance of man, as are higher types of animals. However, the vitality of some species under the strain of famine is remarkable. Miss Fielde has shown (Tenacity of Life in Ants) that the workers of Cam- ponotus americanus may live nine months without food. They thus rival, in their ability to endure a prolonged fast, the queens that go solitary and draw upon their reserve tissue enough for self-sustenance and also to nourish the firstlings of their flock. The common mode of feeding the young, as heretofore described, is by transfer from the nurses’ crops by regurgitation. But a wholly different manner has been observed that is more like our way of giving food to domestic fowl and animals. This grows out of the fact that the larvze of 107 ANT COMMUNITIES Pachycondyla and some other genera are able to feed themselves; perhaps have been educated thereto, though the natural aptitude must have underlain the habit. While lying upon their backs the larvee suck the juices of particles of food given them. The nurses of Leptogenys dismember termite nymphs and scatter the pieces among their larvee, who thrust their beaks into the soft parts and feed thereon. So also workers of Odontomachus will tear off the heads and legs of house flies, cut the thorax and abdomen into pieces and feed them to their larvee. In the above cases the food was not first masticated, as is done by social wasps, but simply cut into pieces to expose the soft parts to the larval mandibles. Adlerz has made like observations of the larvee of Leptothorax, Stenamma, and Pheidole, who are fed with solid as well as liquid food. [Quoted W. 11, p. 709.] Such increase in the variety of food and feed- ing the young must add to the chances of their whole- some survival by lessening the danger of a failure of food, since it greatly widens the field from which avail- able supplies may be gathered. An example of the strange exigencies that befall the inhabitants of an ant commune appears in the case of certain workers of Pheidole commutata that become in- fested with large internal parasites, and are therefore known as Mermithergates. This condition is accom- panied with an enormous appetite, and they con- tinually beset the nurses for food, which they get often at the expense of the hungry larve. The voracious creatures not only ply the nurses with mimetic entreaties, including the out-thrust tongue, but keep up a stridulating chant of solicitation. At times they resort to more vigorous measures, and 108 FEEDING THE COMMUNE seizing a replete, hold down its head with their large forefeet, and compel it to give up the contents of its crop. This greediness has its penalty in times when food is searee; for in order to rid the commune of such voracious and non-productive mendicants, they are killed outright or starved to death by the workers. The honey-ants as studied by the author in Colorado made their night expeditions into a scrub-oak copse, and the sweet liquid with which their crops were filled on their return was collected from oak-galls formed upon the twigs and branches! (Fig. 52). But, doubtless, like other Fig. 52—sPRIG OF DWARF-OAK (QUERCUS UNDULATOR), WITH GALLS EXUDING DROPS OF SWEET SAP ants, they know the value of aphides, and, as the seasons change, gather from them and from other sources the 1 Nature’s Craftsmen, chap. x. 109 ANT COMMUNITIES supphes for current sustenance, as well as for their peculiar mode of providing for future wants. [McC. Nek Lass Among the honey-ants the workers, though varying in size, are structurally alike (Fig. 53). Yet certain indi- viduals, quite independent of caste, and following an impulse unknown, but apparently fixed in the germ and Fig. 53—-THE DIGESTIVE TRACT OF A HONEY-ANT Showing asophagus, a, as a nearly straight tube from the mouth to the abdomen. c—Crop. gz—Gizzard. s—Stomach early manifest in the callows, begin to store up food in their crops, and thus develop into rotunds or honey- bearers (Fig. 54). It must be allowed to be a curious manifestation of communal philomyrmicry which causes one of the most.active of creatures to become little more than an animated honey-pot, that the food supply of its fellow-formicans may not lapse. But so we find it; and, after all, it is little more than a development to its cli- max of an instinct that urges ants of other species to charge their crops with an excess of food in order to impart it to the commune dependents. The insectivorous habit of ants has been utilized as a check upon the increase of certain destructive cater- pillars. The author’s attention was called to an article on the “ Utilization of Ants as Grub-Destroyers in China,” by Doctor Magowan, of Wenchow, and this led him to con- 110 FEEDING THE COMMUNE SnAg OE “\ NS ‘ Rn mess ‘. : \ Sah. eae \ t ed Lit ef LIZ WN y= Noes Seen ao Fig. 54—Honey-bearers or rotunds (a) in situ in a natural nest. b—Same with workers in an artificial formicary sider at some length whether and how far those insects could be used in the United States.t. [McC. 8, p. 268. ] 1The information was received from a copy of the North China Herald of April 4, 1882, sent me by the Rev. Dr. Hunter Corbett, a Presbyterian missionary at Chefoo, China, | 111 -ANTS g. 55—ABDOMENS OF HONEY 1 in various to the honey-bearer ge 113 ment of the crop minor ve develop gressiv worker forms—from the worker- Showing the pro See footnote pa FEEDING, THE COMMUNE According to Dr. Hunter Corbett, in many parts of the province of Canton, where cereals cannot be cultivated profitably, the land is given up to orange-trees. These are subject to attack by a species of ‘‘worms”’—the specific name is not given—which work serious injury in the orange orchards.