CHAPTER VIII.

THE HISTORY OF MYRMECOLOGY AND THE CLASSIFICATION OF ANTS.

“Les mœurs des fourmis sont si variées qu'il est important de connoitre à quelle espèce se rapporte chaque trait d'industrie, chaque particularité de leur histoire."-P. Huber, "Recherches sur les Mœurs des Fourmis Indigènes," 1810.

Myrmecology has been more fortunate than many other branches of entomology in the men who have contributed to its development. These have been actuated, almost without exception, not by a mania. for endless multiplication of genera and species, but by a temperate and philosophical interest in the increase of our knowledge. The reason for this fortunate circumstance is probably to be sought in the ingenium formica male habitat, the fact that ants are small, homely organisms with nothing to attract the amateur who cares only for size and beauty of form and color. This is, perhaps, regrettable as it has

FIG. 67. Worker of Sima allaborans of India. (Bingham.)

certainly retarded the accumulation of study materials in our museums and private collections, and has left the subject in the hands of a few devotees. But this disadvantage is not so great as might be supposed, because the species of ants, though far less numerous than those of butterflies and beetles, are nevertheless more abundant in individuals and hence more easily obtained. Undoubtedly the great difficulty of the study has had much to do with limiting the number of myrmecologists, especially in America. Here the literature of descriptive myrmecology, which is widely scattered through somewhat obscure serials and is written very largely in the German, French and Italian languages, has remained quite inaccessible to the average student. Even a knowledge.

of the literature, however, does not overcome all of the difficulties of the subject, for the species of ants often differ from one another by characters too subtle and intangible to be readily put in words. The "habitus" of a species, as every taxonomist knows, is something one may take in at a glance, but be quite unable to express without wearisome prolixity. Hence the importance of large collections, thoroughly studied and identified and accessible to every student. Such collections have been lacking in America and those interested in ants have had to send their specimens abroad for identification. This is time-consuming, to say nothing of the inconvenience to which it often puts the overworked specialist.

Ants, like other organisms, may be studied from at least three different points of view, according as the observer is most interested in their classification, or taxonomy (including geographical distribution), their morphology (anatomy and development) or their ethology, that is, their functional aspect (physiology and psychology). Even in such a small group of insects these various subjects are so extensive and intricate that very few observers have been able to cultivate them all with equal success. This has, perhaps, been accomplished only by ✓ Emery and Forel, each of whom has devoted more than forty years of unremitting study to the ants. Other workers have been able to cultivate only one or at most two of the subjects above mentioned. fore considering the classification it may be well to sketch with the utmost brevity the history of myrmecology in its various branches.

FIG. 68. Worker of Trigonogaster recurvispinosa of Western India. (Bingham.)

Be

The foundations of the taxonomy of ants were laid in the closing years of the eighteenth and the opening years of the nineteenth century by Linné, Fabricius and Latreille. Linné (1735) in his "Systema Naturæ briefly described eighteen species, eight from Europe, eight from South America and two from Egypt as belonging to the single genus Formica. Some of these, like other well-known Linnæan species of animal and plants, are collective species, that is, they embrace several of what would now be regarded as distinct species. Fabricius (1804), besides describing a number of additional species, created five more genera: Lasius, Cryptocerus, Atta, Myrmecia and Dorylus. Of course, none of these corresponds fully to the genus bearing the same name at the present time. He still retained the great majority of the species in the Linnæan genus Formica, but divided it into two purely artificial categories, one for the species with, and one for the species

without spines on the thorax. Neither Linné nor Fabricius seems to have paid much attention to the habits of the ants.

The third and by far the most important of the pioneers in myrmecography was Latreille (1798b, 1802b). He collected the ants of Europe, studied their habits assiduously and described many species that had been overlooked by his predecessors, including a number of interesting forms. He produced good descriptions of nearly a hundred species which he had himself examined. All of these he placed in the single genus Formica which he divided into nine "families ": the Formice arcuate (corresponding to our present genera Camponotus and Polyrhachis), camelina (our Formica, Lasius, Myrmecocystus, Ecophylla and Dolichoderus in part), atomaric (our Dolichoderus in part, Tapinoma and Acantholepis), ambiguæ (Polyergus), chelata (Odontomachus), coarctate (Ponera, Pachycondyla, Neoponera, Ectatomma, Myrmecia, etc.), gibbosæ (Atta, Pheidole, Messor, Pogonomyrmex, etc.), punctoria (Eciton, Myrmica, Tetramorium, Myrmecina, Leptothorax, Solenopsis, etc.) and caperate (Cryptocerus, Ecophylla). It is impossible to run over this arrangement without admiring Latreille's acu

FIG. 69. Worker of Aphanogaster beccarii of the Indomalayan region. (Bingham.)

men in so clearly forecasting the limits of many of our modern subfamilies, tribes and genera.

For nearly fifty years after the publication of Latreille's work systematic myrmecology stagnated, till a revival of interest in the subject began to set in about the middle of the past century with the work of Nylander and Mayr. Both of these authors devoted themselves to a careful study of the European species, Nylander to the boreal, French and Mediterranean, and Mayr to the Austrian and eventually to the whole European fauna. Both authors, but especially Mayr, defined the genera and species more accurately than any of their predecessors. Later Mayr extended his studies to the faunas of foreign countries and published several important works on the ants of Asia, Africa, Australia, and North and South America. Forel, in commenting on his work says: "His remarkable perspicacity in creating genera, and in general in the distinction of the comparative value of zoological characters, and the minute exactitude of all his writings, which represent a vast amount of labor, have raised myrmecology to the rank of

the best known portions of entomology." A well-known English hymenopterist of the same period, Frederick Smith, undertook a similar universal study of the ants, basing his descriptions on the numerous specimens from all parts of the world in the collections of the British Museum. Many of his species are so inadequately described that the writers of today are obliged either to discard them or to make pilgrimages to the British Museum for the sake of consulting the types from which they were drawn, and while some of his species bear appropriate or even elegant names, and have been identified after much labor with a fair degree of certainty, his generic distinctions give evidence of deficient classificatory sense.

During the latter half of the nineteenth century a considerable number of local European ant faunas were published and our knowledge of the ants of other lands grew apace. Adlerz studied the ants of Sweden; Ernest André of France, Europe and North Africa; Bos, Meinert and Wasmann of the Netherlands; Curtis, Saunders and F. Smith of England; Forel of Switzerland; Emery of Italy; Gredler of Tyrol; Nassonow and Ruzsky of Russia; Schenck and Förster of Germany, while some accomplished entomologists like Roger, Gerstaecker, Shuckard and Westwood evinced a greater interest in the exotic genera and species. Nor was this activity confined to Cardiocondyla venustula the recent ants. Heer, Mayr, Emery, Ernest (Origi- André and others published descriptions of many fossil species preserved in the Baltic and Sicilian ambers and in the strata of Oeningen and Radoboj.

FIG. 70.

Worker of

of Porto Rico. nal.)

Among this group of diligent investigators two are facile principes, Emery and Forel. In 1874 Forel published at a remarkably early age what must always be regarded as one of the finest natural histories of any group of insects, the "Fourmis de la Suisse," a work to which the student must constantly turn both for information and encouragement. Emery and Forel, who both began to publish in 1869 and have continued ever since to make important contributions to our knowledge, combine an excellent zoological and philosophical training with rare. judgment and acumen. Building on the excellent foundations laid by Latreille, Nylander and Mayr, they have been able to make our knowledge of the ants more complete than that of any other family of the vast Hymenopteran order. Not only have they perfected the

system of the European species, but they have published excellent monographs and revisions of the faunas of other continents, so that the student of today finds it a comparatively easy task to continue the work.

Although the ant-fauna of North America is vastly richer than that of Europe, few of our entomologists have cared to study its taxonomy and as a rule these few have been poorly prepared to undertake the work. Species have been described by Buckley, Cresson, Fitch, Haldeman, McCook, Norton, Pergande, Provancher, Scudder, Viereck and Walsh, but the really valuable work on our fauna has been accomplished by Mayr, Emery and Forel.

FIG. 71. Worker of Stereomyrmex horni of Ceylon. (Bingham.)

The study of ant ethology has had a more continuous, though perhaps slower, development than the taxonomy. It is also much older, and may be said to date back to the seventeenth and eighteenth centuries, to authors like Wilder (1615) Bonnet (1779–83), Swammerdam (1682), Leuwenhoeck (1695), Gould (1747), De Geer (1778) and Christ (1791). The subject does not begin to assume definite form, however, till we reach the writings of Latreille (1802) and especially of Pierre, the son of the celebrated François Huber. P. Huber's work entitled "Recherches sur les Moeurs des Fourmis Indigènes " published in 1810, is perhaps the most remarkable of all works on the habits of ants. It has been widely quoted and has never ceased to be an inspiration to all subsequent workers. It covers much of the subject of the habits of ants in an attractive and luminous style and abounds in accurate and original observations. The most interesting portions of the work treat of the slave-making habits of the sanguinary ant (Formica sanguinea) and the amazon (Polyergus rufescens). Huber was not only the first to discover and interpret the symbiotic relations of these species but his account is so complete that even Forel could add to it little that was really new. Huber also observed the relations of the ants to the aphids and of the various castes to one another and correctly interpreted the origin of colonies.

Since the publication of Huber's work the habits of ants have been studied by an ever increasing number of investigators. The most comprehensive contributions have been made by Forel and Emery, but important work has been done by Adlerz, Ernest André, Bates, Belt, Bethe, Brauns, von Buttel Reepen, Ebrard, Escherich, Goeldi, Heer, J. Huber, von Ihering, Janet, Karawaiew, Lameere, Lespes, Lubbock, Mayr, Moggridge, Reichenbach, Reuter, Rothney, Santschi, Sykes,