Willi Hennig, 1913-1976 - A Biographical Sketch

by Dieter Schlee

[The following is a translation of "Schlee, D. 1978. In Memoriam Willi Hennig 1913-1976 Eine biographische Skizze. Entomologica Germanica 4:377-391" through the kind permission of the publishers, Dr. E. Naegele, E.Schweizerbart'sche Verlagsbuchhandlung, Science Publishers (http://www.schweizerbart.de). We have not included the bibliography or the three figures (see captions at the end) from the original paper. Eds.] 

Abstract. An outline of Professor Dr. Willi Hennig's life history and an abstract of his work on zoology and phylogenetic systematics, etc. are compiled, including some background information originating from his family and from the author's experience with him in his Department of Phylogenetic Research at Ludwigsburg.

"At close scrutiny, the much-maligned systematics turns out to be a very important science of its own. While its sole role in zoology was formerly one of classification, in the course of time it was given the great task, supported by comparative anatomy, palaeontology, experimental studies, etc., of investigating the relationships of animals and their development based on the theory of evolution. The ultimate aim is a system which represents a 'natural history of creation' in the most succinct form possible."

From a high school essay by the 18-year-old Willi Hennig.

1. Introduction.

Professor Dr.-phil. Dr. rer.nat.h.c. Willi Hennig died during the night of November 4, 1976 in the 63rd year of his life. A sudden cardiac arrest took him without warning from a life that was rich in human terms and extremely productive in scientific terms. Until the evening he had worked on the new edition of his book "The larval forms of the Diptera" with his usual intensity and had then reminisced with his family about their last holiday in Crete.

He will be sorely missed by his family - his wife, his three sons and their families; by the Department of Phylogenetic Research at the State Museum of Natural History in Stuttgart and Ludwigsburg which he headed since 1963; by a wide circle of international scholars interested in phylogenetic systematics whose spokesman he was; by many dipterologists all over the world who have lost in him the expert with the most comprehensive knowledge; and by many researchers and students who received valuable suggestions from his wealth of knowledge: as co-editor1 of the "Zeitschrift für Morphologie der Tiere", "Zoomorphologie", and "Das Tierreich", as consultant for "Entomologica Germanica" and "Systematic Zoology", and as author of the textbooks "Taschenbuch der Zoologie", "Stammesgeschichte der Insekten", the chapter "Diptera" in the "Handbuch der Zoologie", as reviser of 14 families (among them the Muscidae and Anthomyiidae) in the series "Die Fliegen der palaearktischen Region" edited by E. Lindner and as author of numerous publications on phylogenetic systematics and many specialized investigations. His published work2 adds up to more than 9,000 pages and thousands of drawings he had made himself; but even these monumental figures cannot adequately express its scientific importance--we have to include the unusually broad spectrum and the deep exploration of his fields of study and to point to numerous other publications which were influenced by his suggestions in order to give some idea of the impact of his work.

 2. Chronology 1913-1932 and the Principles of the Phylogenetic Approach.

He was born in Dürrhennersdorf near Zittau in Saxony on 20 April 1913 as the eldest of three sons--his father was a railway official--and from his early years onwards his family encouraged him to be active and to develop perseverance. In addition to attending the village school, he was tutored in English, Latin, and French by a retired physician. His schooling was so effective that he was allowed to skip one grade when he transferred to grammar school in Dresden; it can be assumed that his later interests had their roots in his activities during these years. He not only collected beetles and butterflies and started a herbarium (his other favourite pastime was going for a ride in a locomotive, as he fondly recalled), but also visited regularly the Zoological Museum in Dresden during the years he attended grammar school (with emphasis on modern languages) in Dresden. There he also met Dr. W. Meise and Dr. Klaus Günther.

How deeply Willi Hennig had already adopted the phylogenetic approach and become familiar with the broad field of (comparative and analytical) zoology at that time can be seen with surprising clarity from an essay he wrote as assignment in the subject "German" and entitled "First essay. 4 May 1931. The position of systematics in zoology." Willi Hennig had just turned 18 at that time. Fortunately, the original of this essay--written in Gothic script in an exercise book--has survived the subsequent turmoil ,of the war and the postwar period and is still in possession of his family. It has been published posthumously: Hennig (1978).

In his essay he treats mammals, marsupials, birds, butterflies, bivalves, Artemia, etc., some of which accompanied by illustrations, provides comparisons of the systems of the entire higher zoological categories from Aristoteles to Siebold-Leuckart, and deals with comparative morphology, palaeontology, zoogeography, behaviour, etc., all of which reveals his wide interests and his occupation with zoological literature.

This essay shows his enthusiasm for systematics in terms of phylogeny, his almost impatient need to emphasize its general importance, -to fight against improper superficiality, to give reasons for various misinterpretations, etc.; and it also expresses his views that relationships and systematics are identical ("...clarification of relationships and thus systematic affinity ....”). He gives several examples of convergence (in a wider sense, of course, since he does not differentiate between convergence s-str. and parallelism) being responsible for false phylogenetic conclusions; and that this can be verified by testing is for him an important realization. Of course, we cannot expect to find, in this school essay, the definition of the term “synapomorphy" which he coined much later.

However, its meaning, i.e. common possession of a unique character (which cannot be proved to have evolved several times, etc.) as evidence of relationship, is already foreshadowed in the following example. "Most recently, similarities in certain modes of behaviour have been used to clarify relationships and thus systematic affinities: Heinroth believes that he can infer a closer relationship between Monticola saxatilis L. and the redstarts because of the characteristic and unique tremor of the tail which is common to both."

The two words "characteristic" and "unique" were not emphasized in the original, but have been underlined here to indicate that he had searched for evidence of  relationship even then in terms of the succinct criterion which he used later (e.g. Hennig in Hennig & Schlee, in press), namely "a particular character state shared by all members of the group" and "not present in any taxon outside the group."

Although he did not universally apply this kind of argumentation in the essay, it is nevertheless interesting to note that he was aware of it--and that he used the   example as a kind of working hypothesis (in fact, he should have cited additional    characters, "conflicting evidence", etc. both in support and in rejection of Heinroth's interpretation). Incidentally, Willi Hennig did not mention that the use of common primitive characters as evidence of relationship may be deceptive; instead he emphasized the dangers of convergent evolution. 

The exercise book with the 29 page essay provides further clues: it reveals that his approach to writing, his style, his argumentation and presentation had already been developed during his school days: Like in his later manuscripts, the sentences must have poured forth in a rapid stream and without requiring any subsequent editing. Some features uncommon in a school essay [abbreviations, deletions, parts of words squeezed into a line] seem to suggest that a sentence had to be completed as fast as possible to make room for the next thought. His flowing style which casually juxtaposes different points of view or themes and his preference to disregard any formal structuring are already evident. The use of clear ink drawings for illustration was another practice dating back to that time. No doubt he wrote the text without prior draft (as he would do later when key words and index cards were often all he needed as aid to memory). [This may explain why he left the deletions in the text, why he placed a table with explanations as a three-page insertion within a single sentence, separated by two commas, and why he wrote 'German essays" on the cover of his exercise book, with the title of the essay inside, although the exercise book    accommodated only that one essay.] Incidentally, his essay was marked "very good" and received the following comments from his teacher (Schm = Schmidt?): "This essay is quite a creditable attempt at giving a critical treatment of the specific field of study of the author. It is not merely concerned with compiling facts but occasionally offers some original ideas as well." 

The first paper by the 19-year-old W. Hennig, with W. Heise as co-author, on the      snake genus Dendrophis appeared as early as 1932. A continuation of the paper, again written by these two authors, was published in 1935.

W. Hennig's interest in bird (e.g. in the above-mentioned school essay) and reptile taxa may very well be significant, all the more so since he was joined by M. Heise who is well known as an ornithologist. W. Hennig regarded birds as part of the group Reptilia and concluded that Crocodylia and Aves are sister groups--while, for example, E. Mayr considered this to be absolutely impossible [he called it "absurd" although he did not question the characters shared by Crocodylia and Aves and their interpretation as synapomorphy; see also Hennig's (1974: 289) reply to Mayr].

1932-1939: Student Days and First Positions and Publications

After graduating from grammar school (1932) with excellent grades (except for physical education), he started his studies in zoology, botany, and geology at  the University of Leipzig. As in his school days, he was given special status: he did not have to meet the general requirement stipulated by the Director of the Zoological Institute, Mr. Meisenheimer, that the major laboratory could only be attended after completion of the two-semester basic course. He was permitted to attend the laboratory in his first year since he had already acquired the necessary background knowledge during his grammar school days. Intensive work enabled him to complete his thesis (Contributions to the study of the copulatory apparatus of the cyclorrhaphan Diptera) and his studies by April 1936, i.e. when he had reached age 23.

At that time he had already published eight more papers, mainly on Diptera, among them "Structure and relationship of the Kerguelen fly" (1934), but also, for example, a 68-page revision of the genus Draco (Agamidae); a total of 500 pages including his thesis. After a brief period as a trainee at the State Museum of Zoology in Dresden, he joined the German Entomological Institute of the Kaiser-Wilhelm-Gesellschaft on I January 1937, initially under a grant from the German Research Association and subsequently, as of 1939, as a staff assistant.

By 1939 the list of his publications comprised as many as 41 titles with a total of 1065 pages. These papers dealt mainly with taxonomy and the copulatory apparatus of widely different families of Diptera (among them the first seven families for E. Lindner's "Flies of the Palaearctic region"), but were also on subjects like "On some regularities of geographic variation in the reptile genus Draco L.: "parallel' and .. convergent" race formation", the "Problem of classifying higher categories", and "On the question of the systematic position of Braula...", on beetle larvae and the first fossils in amber (1938: Diptera: Rachiceridae; 1939: fleas).

 1939-1945: Military Service and Draft of the "Principles of a Theory of  Phylogenetic Systematics'

He received a shortened basic military training in the infantry starting in the winter of 1938 until the spring of 1939 and was conscripted when the war broke out. He served as an infantryman in Poland, France, Denmark, and Russia where he was wounded in 1942 and sent to several field hospitals. He was given a six month "working leave" in Berlin and later received instructions from the Medical Academy of the Army in Berlin to work in the field of malaria control in Greece and Northern Italy (specifically in Venice and environs). He continued this work not only until the end of the war but also during the time he was in [British) captivity.

He wrote the draft of his fundamental work on the "Principles of a theory of phylogenetic systematics" in the period between the end of the war and his return home. It was published in 1950 (see below) and the original manuscript is in possession of his family (Fig. 1). He wrote it in an Italian notebook, about 21 x 31 cm in size, with a heavy cardboard cover. Although it does not contain a title, it begins with a two-page table of contents (which was later edited only slightly for publication), followed by the flowing text which for the most part fills almost whole pages. It gives the impression that the manuscript was put on paper in an almost continuous, uniformly calm flow (barely interrupted by occasional splashes of his fountain pen). Chapter follows chapter almost without any space in between--it seems additions or changes were not contemplated. (Despite the fact that additional sheets were added, not all of the chapters listed in the table of contents could be accommodated in the 170-page notebook.)

This manuscript is not the only scientific work W. Hennig produced during the war. The list of publications indicates that 25 papers were published between 1940 and 1945, among them two on his work in epidemic control, some revisions of the Acalyptratae for E. Lindner's "Flies of the Palaearctic region", studies on the relationships of "The genera combined within the 'Phytalmiidae'” and of the Pupipara, the “Catalogue of the Diptera of Formosa”, a "Contribution to the problem of the 'relationships between larval and imaginal systematics"', and several studies on larvae.

 These publications are by no means manuscripts dating from the prewar years, but were indeed written during the war since he used to work  wherever he was and no matter where he was. He received the necessary background material from his wife through the army postal service. She managed to obtain the necessary material, to look after proof-reading, etc., despite the uncertain times and her care in bringing up their children. It seems amazing how much the two were able to accomplish in those times.--However, some material was lost, for example, the entire manuscript for "Bronn's Classes and Orders of the Animal Kingdom.' The original burned in a safe in Berlin. The carbon copy was lost later during the last weeks of the war. W. Hennig never started writing the manuscript anew.

He also encountered difficulties in getting a rather long paper on Phlebotominae published: this manuscript could not be printed during the war because of paper supply problems despite the fact that he directed inquiries to several publishers, even in Austria. The manuscript was not considered "essential to the war effort" and printing of the manuscript was therefore not authorized. This manuscript, too, has never been published.

The terror of war continued to have a lasting effect on him even in his later years. He himself, seriously wounded, was one of five survivors of an entire company and one of his brothers did not return from Stalingrad. Even much later, particularly during the time of the annual siren testing, he used to remark how intensely his war experiences had made him aware of the limitations imposed on his creative output and how much he felt obliged to use the available time to the utmost.

1945-1950: Postwar Period, Completion of the "Principles ..." and of the "Larval Forms of the Diptera"

Although his family continued to live in Leipzig after they were bombed out during the war, W. Hennig was discharged from captivity to West Germany since there was concern that he might end up as a Soviet prisoner of war should he return to the "Eastern Zone" of Germany. So he stayed in Hamburg, Plön, and Göttingen--for six weeks at a time because this was the maximum period for which ration cards were issued in each municipality. In November 1945 he crossed the East German border illegally to join his family in Leipzig. Fortunately, the situation was already defused since it was well known within the Zoological Institute that he had never supported the Nazi regime either by being a member in any of its organizations or by any other activities.

 On 1 December 1945, at the age of 32, he was appointed Acting Director of the Zoological Institute at the University of Leipzig. He resigned from this position in Leipzig on 1 April 1947 in order to be able to return to the German Entomological Institute which had been moved to Mecklenburg. On his return to Berlin, he expanded the manuscript of the "Principles ... of phylogenetic systematics" which he had written while in captivity. He worked on it in a cold room and by candlelight during the 10 months of the Berlin blockade in 1948. (The family received a coal ration of 25 lbs. for the entire winter plus 75 lbs. extra for the three small children; they all collected horse chestnuts and acorns as additional fuel). Paper continued to be in short supply when the "Principles..." were ready for printing (which explains the absence of an index and the much too small edition).

Starting in April 1947 when he returned to Berlin, he also continued-to work on the "Larval forms of the Diptera" which he had begun before the war and which was published in 1948. The large card index had been moved to the German Entomological Institute in Mecklenburg where it was found after the war in disarray, yet still complete. He was now also in charge of organizing the return of the museum holdings. The building in Berlin was intact but had not yet been released by the [U.S.] occupying power and so the mansion of a brewery owner in the east end of the city was used to accommodate the collections and the library which had fortunately survived the war without losses. W. Hennig had thus regained his old position at the German Entomological Institute.

 In addition to the "Principles" and the "Larval forms", he published other papers on the morphology and systematics of Diptera during the period from 1945-1950 including short essays, i.e. "Problems of biological systematics" and 'Explanation of terms used in phylogenetic systematics" (the two essays were published in "Forschungen und Fortschritte" (Research and Progress] 21/23: 276-279, 25: 137-139).

1950-1963: Berlin

During this particularly productive period he published 35 papers in addition to the papers mentioned above. Among the 35 papers were such universallyimportant works like the "Critical comments on the phylogenetic classification of the insects" (1953), "Diptera" in the "Handbook of plant diseases" (1953), "Wing venation and classification of the Diptera with special reference to the fossils described from the Mesozoic" (1954), "Systematics and phylogeny" (1957), the first edition of 'Invertebrates I and II" in the 'Textbook of zoology" (new editions followed later, the newest will be published shortly), "The dipterous fauna of New Zealand as systematic and zoogeographical problem" (1960), the important monograph of the "Muscidae" for "Lindner', etc. The revised edition of the "Principles..." was also completed in 1961 and sent to the United States for translation and printing (he did not see this work again until it was published in 1966 under the title "Phylogenetic Systematics”).

Finally, the time approached for Dr. H. Sachtleben, the Director of the German Entomological Institute, to retire. W. Hennig, who until then was Deputy Director, was nominated as successor when the construction of the "Berlin Wall" on 13August 1961 abruptly changed the situation. Until then W. Hennig had commuted daily from his home in West Berlin to the German Entomological Institute which is located in the Eastern Sector of Berlin in the belief that the division of the city was only temporary-- in the same way as his general attitude was governed by the hope that Germany would eventually be reunified. He resigned from his position with the German Entomological Institute after the Berlin Wall was built. He stayed on in West Berlin for almost two years and taught at the Technical University.

Until his death he regarded Berlin as his true home, not only because of his ties with the German Entomological Institute but also because of the entire cultural atmosphere.  

1963: Move to Stuttgart/Ludwigsburg

The Smithsonian Institution in Washington and Prof. E. Hardy from the Department of Entomology of the University of Hawaii in Honolulu offered W. Hennig a new sphere of activity. However, he decided to stay in Germany because of his sons' education and also because he felt a need to remain close to the cultural heritage of the ancient Greco-Roman Europe, as he expressed it on several occasions. Prof. A. Kaestner, Munich, and Prof. E. Schüz, Director of the State Museum of Natural History in Stuttgart until 1969, used their influence to secure for him a department of phylogenetic research at the Stuttgart Museum (Ludwigsburg Branch). Thus he moved with his family to Ludwigsburg in April 1963.

Reports on the activities of his department are included in the annual reports of the Museum and are published in: Jh. Verein vaterl. Naturkunde Württemberg 120: 38-39, 121: 23, 122: 23-24, Jh. Gesellschaft Naturkunde Württemberg 124: 19-21, 33-34, 125: 30-31, 126: 16-17, 127: 19-21, 128: 16-17, 129: 21-22, 130: 405-406, 131: 223, etc.  

1963-1976: The State Museum of Natural History in Stuttgart Ludwigsburg; Focus on Fossil Studies etc.; Teaching Activities

Fossil Studies

Cut off from his accustomed collections and libraries in Berlin with their vast holdings unique in Germany, he searched for, and found, a "new niche' for his future focus of activities: the study of fossils in amber. Among his many previous papers, he had published two papers on Diptera and Aphaniptera in Baltic amber as far back as 1938 and 1939 and since that time he had wanted to study these fossils in greater detail. He had learned that the Königsberg fossil collection had been moved to Göttingen where Prof. A. Seilacher assisted him in his search and arranged for the loan of the extensive material, as did Prof. O.H. Walliser.

In the period from 1964-1972, W. Hennig thus published 17 papers on various groups of Diptera from the Baltic amber (as well as three papers on fossils from the Lebanon amber, see below) which in theory and practice went far beyond everything previously published in this field.

His studies of the fossils in amber yielded several important results: The book "Phylogeny of the Insects” (1969, published by W. Kramer, Frankfurt) grew out of his extensive file cards which he always prepared, namely those dealing with "Localities of Palaeozoic and Mesozoic insects", "Phylogenetic evolution of the insects", and "Aims, methods and limitations of phylogeny." This book does not only provide a critical phylogenetic review of the described Palaeozoic and Mesozoic fossils of all insect groups but also an extremely important contribution to the development of his theory of phylogenetic systematics.

In his search for amber material with fossil inclusions he came upon amber from Lebanon (an amber which was then still considered to be non-fossiliferous). Thanks to the collaboration with his department on the one hand and with the members of the Geological-Palaeontological Institute in Tübingen3 on the other, his search produced the greatest collection of fossils trapped in this resin from the Lower Cretaceous--the geologically oldest fossil-bearing "amber" known to date.

 In 1966 he was invited to Canada by the Entomology Research Institute, Ottawa. Although he had suffered a mild heart attack a few months before his scheduled departure, he felt obliged to undertake the trip. He stayed in Canada from August to December 1967. This trip again culminated in extensive scientific studies and publications. He also visited scientific institutions in New York, Washington, Urbana, and Chicago during a one month stay in the U.S.A. Shortly before the end of his visit he suffered another heart attack. His doctors urged him to return home immediately--yet he insisted on keeping his promise and completing the scheduled two weeks of collecting. Fossils in amber were again at the centre of his investigations.

Monographs

Another focus of his work was the taxonomic-systematic revision of the dipterous  families Muscidae (1955-1964) and Anthomyiidae (1966-1976) as his 13th and 14th contributions to "The flies of the Palaearctic region" edited by Professor E. Lindner (his friend and colleague from the State Museum of Natural History in Stuttgart/Ludwigsburg). Professor Hennig viewed this task, which he could have confined to taxonomy per se, as a challenge to conduct comparative-morphological analyses to verify not only the taxonomic, but also the phylogenetic relevance of characters and to provide extensive documentation in the form of drawings--always his own (more than 3,000 illustrations, often including several figures of the same form). After examining an enormous amount of material--which he obtained on loan on an individual basis or inspected on location in museums during his holidays abroad--he based his phylogenetic conclusions on broad comparisons which went far beyond the particular group he investigated.

General Works and Supplementary Studies

He used the same approach in his general works, for example his treatment of the Diptera in the "Handbook of zoology." Here as well he went far beyond mere compilation and always considered all morphological and non-morphological criteria in terms of their suitability as phylogenetic evidence. His didactic efforts went to the point of redrawing all illustrations he wanted to include and providing detailed information in the captions in an attempt to achieve a uniform and optimally informative picture.

He also published detailed studies of specific queries whose scope would have exceeded the framework of handbook-oriented treatments. Here, too, he used a broad basis for comparison: His investigation of the wing base of Nematocera also includes information on Mecoptera; the paper on the phylogenetic implications of the hypopygium of Lonchoptera etc. (1976, the last paper he published) also includes information on many other groups of Diptera; he also included many details on musculature (based on sections he had made himself) to substantiate his comments on the views advanced by other authors.

In his last year he worked intensively on the new edition of the "Larval forms of the Diptera" (the publication of his working material is in preparation), on a revised edition of the 'Textbook of zoology" (the 4th completely revised edition is in press), as well as on a general phylogenetic manuscript (its publication is in preparation) and other papers (see list of publications).

Teaching Activities

He needed such multi-faceted work: thus he might work on dipterous larvae in the Museum during the day and in the evening he might, for example, get so involved in non-insect invertebrates that the only time he had left for writing comments on manuscripts he received from his various journals, for opinions requested from the German Research Association etc., were the weekends where he would write heaps of letters in an effort to complete all these tasks quickly and thoroughly.

The lectures which he gave as Associate Professor at the Tübingen University (since 1970) were for him a welcome change from his primarily entomological work at the Museum. In these lectures he discussed, for example, new theories on mollusc phylogeny or coelom evolution. His efforts to keep up and to continuously expand his knowledge in many fields of zoology and to discover phylogenetically relevant evidence were far-reaching and extended also to vertebrates (as is indicated by a manuscript for a book on which he was working). His informed and detailed arguments and questions would occasionally embarrass even experts in their fields.

While he undertook numerous speaking engagements and attended conferences, etc. in his earlier years (for example, in 1963/64 he traveled to Helsinki, London, Rome, Munich, Marburg, and Freiburg, and visited the museums in Helsinki, Copenhagen, Paris, London, Florence, Göttingen, Frankfurt, and Tübingen for study purposes), in his later years he concentrated his efforts on personal discussions on a particular issue to expand his theories and elaborate his methodology, on "filtering out" previous suggestions on phylogenetic evaluation (e.g. in his 'Phylogeny of the insects" and "Textbook of zoology"), and on his own work on specific extant and fossil groups. Insofar as his papers were not intended for publication in other journals, almost all of his papers which he wrote during the time he worked in Stuttgart/Ludwigsburg were published in the "Stuttgarter Beiträge zur Naturkunde", the Museum's own journal.

"Stuttgarter Beiträge zur Naturkunde" is a scientific journal which has been published by the State Museum of Natural History in Stuttgart since 1957 (editor: Dr. K.W. Harde); it has a circulation of 1,000 copies and at the present time copies are still available for purchase (through direct orders or through bookstores) or exchange for other journals.

W. Hennig regarded a discussion of phylogenetic principles among a small group of colleagues, particularly a written or oral discussion with an author on the basis of his manuscript (whose level of work appeared to him worth spending some time on) to be more important than general speaking engagements before a large audience. He perceived serious dangers in having to shorten his argumentations (which might entail misunderstandings) because of the time limitations imposed by lectures; and he regarded the elaboration of certain elements required for lecture purposes as (tedious) repetition of issues he had already discussed on several occasions before; and finally, he missed the personal contact and the stimulus provided by a personal discussion. If he felt that a person was truly interested in phylogenetic methodology, W. Hennig would untiringly answer specific questions, approach them from various angles, and cite numerous examples in support of his arguments without any regard for time or his own projects that may have been scheduled for that particular time.

He realized that many authors (unlike himself) evidently found it difficult to transpose the phylogenetic argumentation from a study on other animal groups used as a model to their own specific animal group, and he therefore made every effort to plant "germ cells' in as many animal groups as possible. This is also the reason why he enjoyed supervising post-graduate students working on a thesis since he expected to encounter here a combination of mental agility, openmindedness, and a wealth of facts.

In order to ensure adequate publication and dissemination of the findings of these theses, he used his influence as co-editor of the 'Zeitschrift fürMorphologie der Tiere" / "Zoomorphologie", together with Prof. P. Ax who shared his views, to get even voluminous manuscripts printed and he strenuously (and successfully) opposed efforts to restrict the size of a manuscript. He repeatedly expressed the view that this journal should act as "a vessel for theses." In his efforts to establish the "germ cells" he tried to increase the precision of the phylogenetic argumentation to a level which the author of a given manuscript could or still would reach; but when he realized that a certain limit was reached (or could not be reached from the very beginning), he would be satisfied with phylogenetically less relevant argumentation and still recommend publication (particularly in cases where the journals in question had less sophisticated phylogenetic ambitions than the ones he himself was involved in). He made this decision in order to preserve the documentary value of a paper dealing, for example, with investigations of rarely studied organs or animal groups. He would then express the hope that the author might perhaps progress and improve upon his phylogenetic conclusions at some later stage, or that others might takeup this particular topic and bring it to a satisfactory conclusion.

He did not like to get involved in the flood of theoretical papers on phylogeny (of every possible shade); he considered many of the papers he had to read because he received them as manuscripts to be intolerable on account of the frequent superficiality in their argumentation which he could not understand, and on account of the constant repetition of ”counter-arguments" which he had refuted before more than once on the basis of specific examples and well-founded reasoning (which the author had not read or had not understood for semantic or other reasons). Against this background, he would occasionally be pleased with papers which at least to some degree followed his approach--in hopes that the authors should not become discouraged and should try to improve.

In addition he was convinced (as he pointed out on several occasions) that in 10 or 20 years' time the wheat would separate from the chaff even without his doing. He wanted to write a new book on phylogeny after he had completed the revision of the "Larval forms"; he felt that this would be the time to deal with individual works.

The massive attack by E. Mayr however did elicit his immediate reaction; Mayr's remarks on monophyly in particular struck at the heart of his phylogeneticapproach. W. Hennig strenuously objected to the dilution of this term (for example through the incorporation of groups which are characterized only by evident non-synapomorphies) in Mayr, as he did vis-a-vis visitors whenever he deemed it necessary. He was also extremely amazed to see that people could be satisfied with formulations of the type 'A, B, and C have a common ancestor and are therefore a monophyletic group" as evidence of relationship and that even when they were given a detailed explanation (for example: man, snail and earthworm also have a common ancestor, but this is no proof that the three are related more closely to one another than to other forms), they did not understand that there was a difference between the above statement and the following formulation and meaning of "...having an ancestor which only share."

Sometimes he felt that the time when his ideas would be generally understood was still in the distant future in view of the endless discussions of elements of phylogenetic methodology which he had explained before to the very limits of achievable clarity and which nevertheless gave rise to spectacular misinterpretations. He overcame his anger over such incidences or difficulties arising from other causes which he considered small-minded and parochial (as they must appear to him given his background, see above) by burying himself in work, a remedy he had already adopted during the war and the postwar period. 

3. Honours

Fortunately, various honours were bestowed on him just in time -- as one, might almost say with hindsight in view of his short life--to give him optimism and confidence regarding the impact of his work. He was awarded the Fabricius Medal by the German Entomological Society in 1953 (i.e. when he was only 40 years old).

 In 1955 he was named Associate Member of the Finnish Entomological Society, Helsinki, in 1959 he was named a Member of the German Academy of Natural Scientists 'Leopoldina Halle, and in 1963 Associate Member of the American Entomological Society, Philadelphia.

In 1968 he was awarded an honorary doctorate by the Faculty of Mathematics         and Natural Sciences of the Free University of Berlin, an honour that had special     meaning for him because of his close ties with Berlin where, one might almost say, he had left his heart and soul and because it was Professor Klaus Günther4, a person he held in extremely high regard, who presented the honorary doctorate and delivered the eulogy (Fig. 2).  E. Schuz provides an outline of the text of the eulogy and a description of the ceremony held at the guesthouse of Dr. K.E. Scheufelen in Stuttgart in Jh. Ges. Naturkunde Württemberg 124:19-21.

  In 1972 the Royal Swedish Academy of Sciences, Stockholm, named him Foreign Member. Special honours were bestowed on him in the form of the Cold Medal of the Linnean Society, London (1974) and the Gold Medal of the American Museum of Natural History, New York (1975). W. Hennig received the latter medal in Stuttgart from the Director of the American Museum, Dr. Thomas D. Nicholson.

 Finally, in 1976, he was named Honorary Member of the Society of Systematic Zoology, New York.  

4. W. Hennig, The Man

In view of his enormous activities one might be inclined to assume that he did not have any interests outside zoology--but that was far from true. He was a music enthusiast and loved Mozart and Handel in particular. For many years he would listen to every Mozart opera broadcast from Salzburg, using a libretto to follow the music. He also attended many concerts and opera performances in Berlin. Later he traveled extensively with his wife, in particular to southern Europe with its beautiful scenery and cultural heritage, and in the course of these travels he became something of an authority on ancient art history. When he learned that someone from his department or from administration intended to go on a trip, for example, to Rome or Florence, he would provide detailed impromptu descriptions and useful suggestions which were greeted with much enthusiasm; he often brought with him stacks of travel books on art history and lent them to colleagues who expressed interest in them. He seemed to know everything there is to know about the cultural treasures, particularly Romanesque and Byzantine art up to 15th century art, of all of Italy (his favourite country--he was also able to converse in Italian), but also of Sicily, Yugoslavia, Greece, France, and Spain, and he acquired this knowledge thanks to his phenomenal memory and his remarkable grasp of major concepts through intensive study.

 He developed a particularly efficient method of getting to see all that he deemed worthwhile on a trip. While he left the organization of a trip entirely to his wife, he would study every available source to learn about the cultural treasures he was interested in; he would copy these items and note down particulars and would then show these sketches to a tourist guide who could then guide him promptly and without wasting any time to the places he wanted to see (Fig. 3).

He also had an opportunity to briefly visit Australia and New Guinea as well as Thailand, the northern part of India and Nepal, and finally Java, Bali, and Burma (where he, of course, searched for Burmese amber).

He would not always tell the destination of his trips, mainly where trips to distant countries were concerned. Sometimes it required many skillful questions to wheedle his secret out of him, and Professor E. Lindner was particularly successful in this. On one occasion Professor Hennig returned to the office after a holiday and showed his unsuspecting audience a photo of himself, in "tiger tops", riding on an elephant in south Nepal. He was pleased as punch when the ladies asked him, despite his holiday suntan, whether the photo had been taken in the Berlin Zoo.

He liked original humour, especially humour with a Berlin flavour, and an equally matched partner like Professor Klaus Günther could inspire him to sparkling and witty repartees. He would recite passages from classical literature in a spontaneous contest with Dr. Gerd von Wahlert-- in Greek, Latin and in German, if necessary. His immense library at home did not only contain books on zoology and the classics, or Humboldt's accounts of his travels (a man he admired and whose portrait on the Orinoco always hung above his desk in the Museum), but he also had books by Karl May, for example 'Winnetou", or the "Leatherstocking Tales" within easy reach. Who would have expected that? -- W. Hennig also liked our dog and used to remark to others with some pride that it had accepted him immediately and liked to accompany us to his office in the Museum, while it would bark at all other members of the Museum staff although it had encountered them before.

During occasional visits to the Museum his grandchildren (he had five) treated him with cheerful and warm affection, which was obviously mutual. Nobody expected that his life would end so soon and so abruptly, he himself included judging from his remarks regarding his plans for the future. The only indication to the contrary was an entry ("to be transferred to Schlee, if necessary") in his personal copy of the Diptera treatise of the "Handbook of zoology" he was using for revision purposes.

In keeping with his wishes (he was averse to any form of personality cult and even disliked the use of his name in connection with the phylogenetic methodology--he felt that 'phylogenetic systematics' should suffice), no official representatives attended his funeral. He was buried in the mountain cemetery in Tübingen with only his close friends and relatives present. His brother, a minister from their home district in Saxony and, like Willi Hennig, a remarkable person of great determination, deep commitment to his work, and profound understanding, conducted the funeral service and found the right words to pay true tribute to the man even without emphasizing the role that zoology had played in his life.

Although Willi Hennig was unable to realize many of his plans, what he had achieved is nevertheless many times more than a scientist could dream of accomplishing in a lifetime. We can assume that the unlimited support and absolute harmony he found in his family were essential for his work. The role ofhis family, and particularly that of Mrs. Irma Hennig, in this monumental achievement cannot be overestimated.

Mrs. Hennig's mathematics and biology studies, her continued interest in these subjects and her active support, in addition to the example set by the father, may well have had a guiding influence in the career development of their sons since all three attended university, two studied biology and chemistry and are now engaged in research work at the Max Planck Institute, while the third son has completed his studies as a secondary school teacher of German and history.

 5. Postscript and Acknowledgment

Although I had an opportunity to catch a glimpse of some of the aspects of Willi Hennig's life in the course of the almost ten years of working with him and talking to him on a daily basis, it was not sufficient, of course, to gain an overall picture of his life. I am therefore grateful to Mrs. Hennig and her sons for their kind cooperation in answering all my questions in preparation of this paper and for review of the manuscript. In particular, I am indebted to Mrs. Hennig for making available W. Hennig's handwritten texts (the draft of the "Principles...", and the high school essay), the list of publications and the photographs. Permission tomake the significant text of the high school essay known to the general public is also greatly appreciated (see: Ent. Germ. 4 (3/4): 193-199; Stuttgart 1978).

6. Bibliography

The complete list of Willi Hennig's publications appeared in: Beitrage zur Entomologie [Contributions to Entomology) 28: (00): 000-000; Berlin 1978. Only a few selected works and relevant papers are listed below.

Footnotes:

1. Obituary by P. Ax (1977)

2. List of publications in: Beiträge zur Entomologie 28 (1); Berlin, 1978.

3. For details see SCHLEE & DIETRICH in: Neues Jahrb. Geol. Paleontol., Monatshefte, 1970:40-50; SCHLEE in: Stuttgarter Beitr. Naturkunde 213: 1-72, 1970; Kosmos (Stuttgart) 1972: 460-463.

4. W. Hennig also expressed this in his obituary for K. Günther, Hennig's last publication in 1976.

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