Journal o Hymendptera Research Volume 1, Number 1 August 1992 CONTENTS MESSAGE FROM THE PRESIDENT 1 PHYLOGENY SYMPOSIUM DEDICATION 2 ALEXANDER, B.A. An exploratory analysis of cladistic relationships within the superfamily Apoidea, with special reference to sphecid wasps (Hymenoptera) 25 CAMERON, S.A., J.N. DERR, A.D. AUSTIN, J.B. WOOLLEY and R.A. WHARTON. The application of nucleotide sequence data to phylogeny of the Hymenoptera: a review 63 SHARKEY, M.J. and D.B. WAHL. Cladistics of the Ichneumonoidea (Hymenoptera) 15 WHITFIELD, J.B. Phylogeny of the non-aculeate Apocrita and the evolution of parasitism in the Hymenoptera 3 INVITED PAPERS AESCHLIMANN, J.P. AND R.D. HUGHES. Collecting Aphelinus spp. (Hymenoptera: Aphelinidae) in southwestern CIS for "pre-emptive" biological control of Diuraphis noxia (Homoptera: Aphididae) in Australia 103 BOHART, R.M. The genus Oxybelus in Chile (Hymenoptera: Sphecidae, Crabroninae) 157 BROTHERS, D.J. The first Mesozoic Vespidae (Hymenoptera) from the Southern Hemisphere, Botswana 119 GESS, F.W. A new southern African species of the genus Celonites Latreille (Hymenoptera: Vespidae, Masarinae) assoicated with the flowers of Wahlenbergia (Campanulaceae) 141 GESS, F.W. and S.K. GESS. Ethology of three southern African ground nesting Masarinae, two Celonites species and a silk-spinning Qmrtinia species, with a discussion of nesting by the subfamily as a whole (Hymenoptera: Vespidae) 145 GRISSELL, E.E. A revision of Perissocentrus Crawford (Hymenoptera: Torymidae) 91 KIMSEY, L.S. Functional morphology of the abdomen and phylogeny of chrysidid wasps (Hymenoptera: Chrysididae) 1°5 KURCZEWSKI, F.E., M.F. O'BRIEN, and M.G. SPOFFORD. Nesting behavior of Podalonia robusta (Cresson) (Hymenoptera: Sphecidae) 235 (Continued on back cover) INTERNATIONAL SOCIETY OF HYMENOPTERISTS Organized 1982; Incorporated 1991 OFFICERS FOR 1992 Paul M. Marsh, President George C. Eickwort, President-Elect James M. Carpenter, Secretary Gary A. P. Gibson, Treasurer David R. Smith, Editor Subject Editors John Huber, Arnold Menke, David Rosen, Mark R. Shaw All correspondence concerning Society business should be mailed to the appropriate officer at the following addresses: President and Editor, c/o Department of Entomology, NHB 168, Smithsonian Institution, Washing- ton, D.C. 20560, U.S.A.; Secretary, Department of Entomology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, U.S.A.; Treasurer, Biological Resources Division/ CLBRR, Agriculture Canada, K.W. Neatby Building, Ottawa, Ontario, Canada K1A 0C6. Membership. Members shall be persons who have demonstrated interest in the science of entomology. Annual dues for members are $25.00 (U.S. currency) per year. Journal. The journal is published once a year by the International Sociey of Hymenopterists, c/o Department of Entomology NHB 168, Smithsonian Institution, Washington, D.C. 20560, U.S.A. Members in good standing receive the journal of Hymenoptera Research. Nonmember subscriptions are $50.00 (U.S. currency) per year. All remittances should be made payable to the International Society of Hymenopterists. The Society does not exchange its publications for those of other societies. Please see inside back cover of this issue for information regarding preparation of manuscripts. Statement of Ownership Title of Publication: Journal of Hymenoptera Research. Frequence of Issue: Once a year (currently). Location of Office of Publication, Business Office of Publisher and Owner: International Society of Hymenopterists, c/o Department of Entomology, NHB 168, Smithsonian Institution, Washington, D.C. 20560, U.S.A. EditoV; David R. Smith, Systematic Entomology Laboratory, c/o Department of Entomology, NHB 168, Smithsonian Institution, 10th and Constitution NW, Washington, D.C. 20560, U.S.A. Managing Editor and Known Bondholders of other Security Holders: none This issue was mailed 28 September 1992 Message from the President In December, 1982 at the Entomological Society of America meetings in Toronto, Canada, a large group of hymenopterists met to discuss formation of an organization devoted to the study of all aspects of the Hy menoptera . From that embryonic meeting emerged The International Society of Hymenopterists with nearly 300 members and still growing as this message was being prepared. During the early stages of development of the Society we had many discussions about the pros and cons of establishing a journal. Finally, in 1990 an editorial board, composed of Arnold Menke, John Huber, Mark Shaw and David Rosen, was elected to search for an editor and begin the process of starting the new journal, and in 1991 David Smith was selected as editor. You have in your hands the results of this effort, the inaugural issue of the Journal of Hymenoptera Research. We hope this first issue will set the tone for the JHR as a major outlet for reporting research on the Hymenoptera in all their glory. This first issue is composed of invited papers from researchers around the world as well as a few papers from the phylogeny symposium presented at the Society meetings held in Sheffield, England, August 1991 . The quality of presentations and diversity of subjects represents a fine beginning for this new journal and I hope it will encourage more members to submit manuscripts for future issues. Editor Smith already has a few manuscripts for the next issue with others expected, so we are off to a good start. This first issue could not have been realized without the time and efforts of several people. On behalf of the Society, I wish to thank the Editorial Committee and in particular Arnold Menke for selecting an outstanding editor, for inviting an excellent group of authors and subjects for the first issue, and for helping in the establishment of guidelines for the future. Dave Smith has spent many hours searching for a printer, preparing the instructions for authors, and finalizing the style for the journal, for which we offer our thanks. I am also very grateful for the following people who offered financial assistance to help get this issue on its way: FOUNDERS ($1000) Richard M. Bohart Karl V. Krombein PATRONS ($500) Franco Borgato BENEFACTORS ($100) E. Eric Grissell Joong-Suk Park In addition there were numerous Sustaining Members ($50) as well as those who included donations along with their dues. To all these generous people, we could not have done it without you! During the last year we had a contest to create a Society logo. The winning design was submitted by Michael Prentice, University of California, Berkeley, who also designed the cover page for the journal. Congratulations and thanks to Mike. Finally, I encourage all members to use the JHR to reach the masses with their important research findings. Where else can you find a bargain of no page charges in the US! Also, please show this issue to your libraries; we need to establish more subscriptions to support the journal. 4Afc/ Paul M. Marsh President Phylogeny of Hymenoptera DEDICATION The first four articles in this issue are selected papers presented in a symposium "Phylogeny of Hymenoptera" at the Second Quadrennial Meeting, Sheffield, U.K., August 11-17, 1991. As the papers from this symposium were going to press, we were saddened to learn of the death of W.R.M. (Bill) Mason during the last days of 1991 . Bill was one of the prime movers in studies of Hymenoptera phylogeny during the last two decades, and his as yet unpublished studies of comparative mesosomatic and metasomatic skeletomusculature and the evidence it provides for phylogenetic analysis of Hymenoptera were well known to many of us through papers read at meetings as well as informal discussions with him. Bill's interest in Hymenoptera spanned many years and covered many groups beyond his usual specialities of Braconidae and Ichneumonidae. He will be greatly missed not only for his regular contributions to hymenopteran phylogeny and classification, but also for his cheerful and open approach to criticism and scientific debate. This first, one hopes, of many collections of papers on hymenopteran phylogeny to be featured in this journal, is dedicated to him. W.R.M. Mason, August 1990, in his office at the Biosystematics Research Centre, Ottawa J. HYM. RES. 1(1), 1992 pp. 3-14 Phylogeny of the Non-Aculeate Apocrita and the Evolution of Parasitism in the Hymenoptera James B. Whitfield Department of Biology, University of Missouri, St. Louis, MO 63121, U.S.A. Abstract. — Recent interest in the higher-level phylogeny of Apocrita has led to the advancement of several competing hypotheses of relationships among major lineages. Nevertheless, some areas of agreement do exist among these hypotheses, providing a base from which further progress can be made. A well-corroborated phylogeny for the Apocrita would be extremely useful for interpreting the evolution of parasitism, among other features, within the Hymenoptera. Comparative studies of parasitoid / host biology are still at a relatively early stage. Most of what is known of parasitoid biology is derived from relatively few taxa of Ichneumonoidea, Chalcidoidea and Scelionoidea, and even within these groups data are extremely sparse. A number of specialized biological features associated with endoparasitoid groups show intriguing patterns of distribution among taxa, but so little is known of these features across all taxa that coherent evolutionary hypotheses concerning these features cannot yet be advanced. It is suggested that more emphasis be given to comparative parasitoid biology, especially within poorly-known groups. Interest in the evolution of the Hymenoptera is certainly not new; broad treatments of the phylog- eny of the order and the evolution of the food habits of its members span at least most of this century (e.g. Handlirsch 1907, Borner 1919, Brad- ley 1958, Malyshev 1968, Iwata 1976, Tobias 1976, Hennig 1981). Only within the past several de- cades, however, have relatively explicit and prac- tical methods of phylogenetic inference been avail- able so that studies of hymenopteran evolution have become repeatable and open to productive criticism. Even more recent is the wholesale recog- nition of the value of specific phylogenetic hypoth- eses for interpreting the evolution of biological traits (e.g. Coddington 1988, Donoghue 1989, Brooks and MacLennon 1991, Harvey and Pagel 1991). Although this by no means implies that studies of hymenopteran evolution prior to the last few years do not continue to be valuable (such careful studies as those of Oeser 1 961 and Brothers 1 975 on Aculeata, for instance, have held up remarkably well to further scrutiny), it is much easier to evalu- ate the more recent ones in the light of the actual evidence that is presented, so that one study builds upon another. In this brief overview I first hope to quickly cover some of the major findings and controversies of recent phylogenetic studies of the higher taxa of 1 Current address: Department of Entomology, University of Arkansas, Fayetteville, AK 72701, U.S.A. Hymenoptera, focusing especially on the non-ac- uleate Apocrita, which were often under-repre- sented and poorly understood in earlier studies. I will begin with the exhaustive literature review and analysis of Konigsmann (1976, 1977, 1978a,b) and continue to the present, attempting to consoli- date some areas of agreement among the various studies and to point out where disagreement is rampant and further study would be most valuable. In the second main segment of this paper I briefly review what is currently known about vari- ous comparative aspects of the parasitoid habit among the groups of non-aculeate Apocrita. I will first focus on the ways in which parasitoids have overcome the problems associated with an evolu- tionary transition from ectoparasitism (the puta- tive ancestral form of parasitic lifestyle in Hym- enoptera) to endoparasitism. There will follow a brief discussion of how some of these parasitoid "strategies" are distributed among hymenopteran higher taxa. Although an attempt will be made to illustrate the value of a phylogenetic perspective in interpreting such comparative data, the major goal of this review is to point out areas where new comparative biological data would add apprecia- bly to our understanding of the evolution of para- sitism in the Hymenoptera. It is one major virtue of a phylogenetic approach that the distribution and depth of comparative data among taxa must be made explicit so that areas of ignorance become clear. RECENT PHYLOGENETIC STUDIES OF APOCRITA Journal of Hymenoptera Research Konigsmann (1976, 1977, 1978a,b) compiled a large, predominantly morphological, data set from the literature, for phylogenetic analysis of higher- level relationships within the entire order Hym- enoptera. His analyses, although rigorous and based on the largest data set produced to that time for hymenopteran phylogeny, suffered from the lack of sufficient characters for many groups, partly because he did not contribute new ones but also because the data set did not include a number of characters already evident to other workers for various groups. Nevertheless, his study did rep- resent perhaps the first rigorous attempt to analyze relationships within the order, and served to highlight the lack of knowledge of, and lack of resolution among, most of the non-aculeate apocritan groups. Figure 1 represents his findings for the Apocrita in an abbreviated form. It is of some significance that his data appear not to sup- port the monophyly of any non-aculeate apocritan groupings above the superfamily level (other than the somewhat controversial one of Evanioidea + (Cynipoidea + Chalcidoidea)), nor of the mono- phyly of the traditional Proctotrupoidea. Masner and Dessart (1967) had already suggested that the Ceraphronoidea should be recognized as a separate superfamily, but the inability of the available data to support the monophyly of the remaining taxa was somewhat surprising. In addition, Konigsmann's analyses suggested that the extant sister-group to Apocrita was most likely the Cephoidea, as Malyshev (1968), among others, had suggested. The next major set of contributions to apocritan phylogeny were made by Rasnitsyn (his papers of 1980 and 1988 are most relevant to the present discussion). In addition to a more thorough knowledge of comparative morphology across many groups, Rasnitsyn's work included compre- hensive consideration of the available fossil evi- dence, much of which had rarely been examined by workers outside of the USSR. Although the details of his phylogenetic hypotheses and classifications evolved somewhat over the years, his 1988 paper largely summarizes the others and provides a concise introduction to the evidence he uses to support his phylogeny. A simplified version of his cladogram of the Apocrita (redrawn and omitting extinct taxa) is provided in Figure 2; Figures 3 and Konigsmann (1978a) Vanhornlldae ACULEATA Fig. 1. Cladogram of non-aculeate Apocrita modified from Konigsmann (1978a). Note especially the almost complete lack of resolution among the basal branching in the suborder. 4 represent his phylogenetic views on subsets of taxa from Figure 1 . Rasnitsyn's ( 1 980, 1 988) cladogram was the first comprehensive, essentially fully resolved phylo- genetic hypothesis for the non-aculeate Apocrita that utilized the principle of grouping on the basis of shared derived features. He produced some radical changes in the higher classification of Hym- enoptera, several of which are still controversial. His classification suffers from two major weak- nesses: 1) his philosophy of classification allows phenetic distinctness to override the strict phylo- genetic branching sequences, so that paraphyletic groups are preserved if distinct enough from monophyletic sub-assemblages, and 2) he did not make use of automated searches for most parsi- monious trees, so that alternative explanations of the data were often not considered. Nevertheless, his work marked a major progressive step in the study of hymenopteran phylogeny. To a large ex- tent, most subsequent studies have focused on Volume 1, Number 1, 1992 Rasnitsyn (1988) other Siricoidea Xiphydriidae Orussomorpha Ichneumonomorpha (Ichneumon oidea) Vespomorpha (Aculeala) Proctotrupomorpha ("Microhymenoplera") Evaniomorpha (Evanioidea + Ceraphronoidea Trigonaloidea + Megalyroidea) Fig. 2. Cladogram of major lineages of non-aculeate Apocrita greatly modified from Rasnitsyn (1988). Fossil taxa have been deleted from this representation of his work, and several putative monophyletic groups have been collapsed into single units. Figures 3 and 4 are more detailed treatments of parts of this figure. testing his ideas and, to date, no comprehensive study has yet superceded his. Rasnitsyn (1980, 1988) established clearly that the extant sister group to the traditional Apocrita is the Orussidae, a relationship that virtually all sub- sequent studies (e.g. Gibson 1985, Johnson 1988; Whitfield et al. 1989) have confirmed and that pro- vides a direct biological link between the Symphyta and the parasitoid habit among the Apocrita. Sec- ondly, he proposed two large groupings below the level of suborder that were not previously recog- nized: the Proctotrupomorpha (Fig. 3 - Chalcidoidea + Proctotrupoidea s.l. + Cynipoidea + Scelionoidea) and the Evaniomorpha (Fig. 4 - Evanioidea + Ceraphronoidea + Trigonalyidae + Megalyridae + Stephanidae). His Ichneumonomorpha corre- sponded to the traditional Ichneumonoidea and the Aculeata, as recognized by Oeser (1961) and Brothers (1 975), remained with its usual boundaries. Of his novel findings, the Evanioidea is the most controversial grouping, in particular the inclusion within it of Stephanidae and Trigonalyidae. Al- though some relationships within this proposed higher taxon have been supported by subsequent studies (Johnson 1988), morphological evidence now suggests (Gibson 1985, Johnson 1988, Mason, unpublished) that the Stephanidae occupy an ex- tremely basal position within the Apocrita and are not closely related to the other "Evaniomorpha". The Proctotrupomorpha grouping h: a been sup- ported in large measure by the comparative skeletomusculature studies of W.R.M. Mason (un- published, there treated as the "Micro-hym- enoptera"). Although no single study has superceded that of Rasnitsyn (1980,1988), the accumulation of ad- ditional comparative morphological studies along the lines of Gibson (1985,1986) on thoracic skeletomusculature, Johnson (1988) on meso- tharacic skeltomusculature and midcoxal articula- tions, Robertson (1 968) on venom apparati, Darling (1988) on the labrum, Whitfield et al. (1989) on the metapostnotum and associated musculature, and the ongoing studies by W.R.M. Mason (in prepara- tion, featuring especially the mesosomal-metasomal articulation and musculature) will clearly be help- ful in further resolving higher relationships within Proctotrupomorpha Rasnitsyn (1988) Monomachidae Austroniidae Roproniidae Heloridae Pelecinidae Proctotrupidae Chalcidoidea Mymarommatidae Scelionidae Platygastridae Fig. 3. Rasnitsyn's (1988) hypothesis of relationships among the "Proctotrupomorpha". The uncertain relationship of Mymarommatidae (but see Gibson 1986) is denoted by dotted lines; otherwise, lack of resolution is indicated by polytomies. Journal of Hymenoptera Research the Apocrita, as will molecular systematic studies now still in their early stages (see elsewhere this issue). Care must be taken, however, to include many of the less easily available taxa, such as Megalyridae, Stephanidae, Trigonalyidae and Orussidae, since these have proven to be critical taxa in determining the larger phylogenetic patterns especially in the early evolution of Apocrita. HYMENOPTERA AS PARASITOIDS If the Orussidae are the sister-group to the Apocrita, as is presently best supported by the available evidence, the parasitoid habit may have had a single, unique origin within the Hymenoptera - in the common ancestor of Orussidae and Apocrita. The biology of orussids is poorly studied, but what is known is consistent with ectoparasitism of xy- lophagous Coleoptera, with the egg laid near the (possibly envenomated) host (Cooper 1953, Powell and Turner 1975, Gauld and Bolton 1988). This biology is remarkably similar to that of basal lin- eages of Ichneumonoidea, Evanioidea (albeit at least some Aulacidae are apparently endo-parasi- toids), Stephanidae and Megalyridae. It is also not terribly different in the host / parasitoid relationship to that of basal groups of Aculeata. Some sort of ectoparasitic habit, therefore, ap- pears to be a groundplan state for many (but not all — note the apparent absence of any extant ectoparasitoids among the Cynipoidea, Scelio- noidea and Proctotrupoidea s.l.) of the major apocritan lineages. Although many variations of behavior and host-parasitoid interaction do exist among ectoparasitoids, and these are of consider- able phylogenetic interest as well, it is among the endoparasitoids that the most extreme elaborations of parasitoid habits have been developed. I would like to focus on what currently can be postulated of the evolution of these various forms of endopara- sitism, based on what is known of comparative parasitoid biology, and what is known, or hypoth- esized, of the phylogeny of the Apocrita. But first a brief discussion of what it means to be a hym- enopteran endoparasitoid. THE PROBLEMS OF ENDOPARASITISM It has been apparent for some time that the condition called "endoparasitism" is really a col- lection of different biological relationships, all of which share the feature of the parasitoid feeding from entirely inside the host organism, rather than from the outside. Evaniomorpha Rasnitsyn (1988) Stephanidae Megalyridae Trigonalidae Megaspilidae Ceraphronidae Gasteruptiidae (incl. Aulacidae) Evaniidae Fig. 4. Rasnitsyn's (1988) hypothesis of relationships among the "Evaniomorpha". Note his inclusion of Trigonalidae and Stephanidae in this assemblage. Many of the features usually associated with endoparasitism are actually associated more closely with koinobiosis (Askew and Shaw,1986; Gauld, 1988; Gauld and Bolton, 1988). This refers to a prolonged, complex interaction with the host (and in endoparasitoids this is with the internal milieu of the host), in contrast to the rapid feeding on moribund hosts more often found in ectoparasitoids (idiobiosis). Some of the most physiologically complex interspecific interactions known to science are between endoparasitic koinobionts and their host organisms, and many of the details of even the best-known cases are not fully elucidated. There are major evolutionary problems to be solved in any transition from ecto- to endopara- sitism, or from idiobiosis to koinobiosis. The defense reactions of the host insects, especially the cellular responses (Gotz 1986, Lackie 1980, Nappi 1975, Salt 1 968, 1 970) must be overcome once the tra nsition is made to development within host organisms. The parasitoid may have to control the physiology of the host to some extent (Beckage 1985, Jones 1985, Lawrence 1986, Stoltz 1986, Vinson and Iwantsch 1980b), or it must prevent the hormonal milieu of Volume 1, Number 1, 1992 the host from controlling its own physiology, or at least use the host's physiological signals to its own advantage (Lawrence 1986, Jones 1985). The solutions to these problems in endoparasitoids appear to have varied greatly from group to group, depending on the options open to them during their evolutionary history. In a few cases the parasitoid may be able to avoid some of the above problems by placing its egg in particular host tissues, or by insulating itself in some way. In at least one species of Eretmocerus (Chalcidoidea), the parasitoid larva, although technically an endoparasitoid, is encased within a capsule that protects it from the internal milieu of the host (Gerling et al. 1990). In most cases, however, more direct interaction with the host is encountered, and parasitoids have a number of "tools" at their dis- posal for dealing with this interaction. For instance, many ectoparasitoids use a venom to temporarily or permanently paralyze the host (Beard 1 978, Piek and Spanjer 1986, Steiner 1986). The evolution of this paralytic venom is an interesting problem in itself. Even phytophagous Siricoidea and Cephoidea secrete compounds (whether homolo- gous or not) that influence either the host plant or fungal associates of the host plant in ways that benefit the developing wasp larva. How the first paralytic venoms might have arisen from any such possible precursors is not known, as comparative biochemical anayses of venoms and associated substances are still in their early stages. The neu- rotoxic and preservative effects of the paralytic venoms of parasitoids are of considerable pharma- ceutical interest, but have not yet been capitalized upon. There are some chemical similarities between some components of these venoms and components of the more well-studied venoms of the social Hymenoptera (for a review of comparative aspects, see Piek 1986 and Leluk et al. 1989), as should be expected since the ancestral biology of Aculeata is ectoparasitism. In endoparasitoids the venom may retain a paralyzing function, or be adapted to influence the host physiology in some way, or act in both ways, or neither (Shaw 1 981 , Piek and Spanjer 1 986, Steiner 1986, Stoltz 1986). Leluk et al. (1989) have shown that the venom of many endoparasitoids contains large protein components not found in the paralytic venoms of ectoparasitic Apocrita. In addition, a number of interactions between venoms and other parasitoid-derived products have been reported (Stoltz 1986, Stoltz et al. 1988, Tanaka and Vinson 1991a,b), so that the extent of host modification or regulation that can be directly attributed to venom is relatively poorly known, and for only a few taxa. The problem is clearly a complex one, but future surveys of venom components from groups in which the phylogenetic relationships and host/ parasitoid biologies are known may suggest functions for some of the venom proteins and aid in the understanding of the biochemical aspects of host/parasitoid interactions (Leluk et al. 1989). In this respect, comparative systematic studies of venom gland structure, as begun by Edson and Vinson (1979) and Edson et al. (1982) may also provide initial insights into venom functions even before biochemical analyses are undertaken. In many braconids and assorted other parasitic Hymenoptera (see below), the serosa or trophamnion associated with the parasitoid egg appears to facilitate the uptake of nutrients by the developing embryo, and may fragment into indi- vidual free-floating cells variously called teratocytes (Salt 1 968, Vinson 1 970, Vinson and Iwantsch 1 980b, Dahlman 1990) or "giant cells" (Jackson 1935, Gerling and Orion 1 973), among other names. That some kind of nutritive function is served by these teratocytes has been suspected by many workers, but other functions attributed to them, such as production of juvenile hormone (Vinson 1970, Joiner etal. 1 973) or fungicidal activity (Fiihreretal. 1978), dissolution of host tissues (Mackauer 1959, Sluss 1968, Gerling and Orion 1973) or overwhelming of the host's cellular defenses (Salt 1968, 1970), are less well established and require much further investigation (Vinson and Iwantsch 1980b, Stoltz 1 986) . However, at least the ju venilizing effects are being corroborated by recent work (Strand and Wong 1991). It is not clear that "teratocytes" are a homologous phenomenon in all of the parasitoids studied; much further comparative morphological and developmental work is required. An addi- tional complication for such studies will be that in some species, teratocytes may be diversifying into different types with age (Strand and Wong, 1991). In some endoparasitoids, viruses associated with the adult female wasps are injected with the eggs, either aided or not by venom effects. These viruses can effectively suppress the immune system of the host as well as cause some other physiological changes (Rotheram 1967, Stoltz and Vinson 1979, Faulkner 1982, Beckage 1985, Blissard et al. 1986, Stoltz 1986, Guzo and Stoltz 1987, Jones 1987, Do- ver et al. 1987, 1988, Schmidt and Theopold, 1991). Journal of Hymenoptera Research Recent studies indicate that at least some of these viruses are integrated into the wasp genomes and are inherited from mother to offspring (Stoltz et al. 1986, Fleming and Summers 1986, Stoltz 1990). The predominant group of viruses that has been stud- ied are the polydnaviruses, of two rather distinct (and probably distantly, if at all, related) types associated with some subfamilies of Ichneumonidae and Braconidae, respectively. Other kindsof viruses are known to be associated with parasitoid ovaries or venom glands, however, and may be of greater significance than is currently realized (Edson 1 981 , Stoltz 1981, Lawrence and Akin 1990, Rizki and Rizki 1990). A more comprehensive overview of the associations between parasitoids and viruses is presented elsewhere in this issue (Stoltz and Whitfield 1992). Inheritance (strictly vertical trans- mission) suggests that at least some virus strains and their relationships should correlate with the phylogenies of the wasps themselves, providing an example of how knowledge of the phylogenetic relationships of the parasitoids can guide lines of productive research in other areas. It should be possible, using modern molecular genetic tech- niques and co-phylogenetic approaches (e.g., Page 1990, 1991, Brooks and McLennan 1991) to inves- tigate the coevolution between the wasps and vi- ruses and their evolutionary interactions with host organisms. Some initial efforts are already being made along these lines (Cook and Stoltz 1983, Whitfield 1990, Stolz and Whitfield 1992). Host/parasitoid physiological interactions are quite complicated syndromes of behaviors and phenomena (Fisher 1971, Vinson and Iwantsch 1980a, 1980b, Jones 1985, Lawrence 1986, Strand and Wong 1991, Thompson 1983, 1990) that might also be found to show phylogenetic trends, inde- pendent of whether the precise "tools" the parasi- toids and hosts use to effect them can be elaborated . Variations occur in whether host ecdysis and de- velopment from one instar to another are possible, and in whether the parasitoid larva uses host hormonal levels to time its own development (Beckage 1985, Lawrence 1983, Shaw 1983). Para- sitoid groups might be found to have general re- quirements for survival that can be satisfied in different specific ways depending on the host group being attacked. Whether any given interactive en- docrine response is selectively advantageous in its current situation or whether it has been inherited as a part of a syndrome from distant ancestors (or both) is seldom known, but could perhaps be ap- proached with additional comparative data. Inte- gration of phylogenetic relationships of parasitoids with information gleaned from repesentative study organisms should help to clarify the evolutionary significance of many of these host/parasitoid en- docrine interactions. However, one major caveat should be added about the use of phylogenetics in interpreting the evolution of complex biological habits. The success of any phylogenetic study de- pends not only upon the accuracy of the biological information put into it, but also upon the sensible division of the often complex biological features into independent, unitary character states. In this respect, detailed comparative studies of the biolo- gies of related organisms, such as those done by Shaw (1983) and Whitfield (in press), may prove a crucial step in the elucidation of more complex evolutionary sequences. Relatively little can be said definitively about the evolution of various parasitoid habits among the Hymenoptera until more well-defined phylo- genetic relationships are known and considerably more comparative biological data is available. However, I attempt below to briefly touch upon what patterns can been seen by reviewing of the literature on apocritan parasitoids, focusing particlarly on the distributions of venom types, viruses and teratocytes among endoparasitoids. It will quickly become obvious that few conclusions should be drawn from the information presently available. Nevertheless, the exercise may be useful in suggesting areas where further information is especially needed. PHYLOGENETIC TRENDS IN HOST/PARASITOID BIOLOGY It has been remarked upon above that the groundplan biology for many of the apocritan lineages is a form of ectoparasitism marked by oviposition on or near a partially or totally inca- pacitated host, usually in a concealed situation. For each infraorder discussed below, I will briefly touch upon the extent to which this groundplan biology is still found in the group, and in what major ways divergence has occurred from this groundplan within the group. Repeated reference to Table 1, which shows the distribution (if known) among taxa of a persistent trophamnion, teratocytes and/ or viruses that may affect the host, may be useful as a quick reference for endoparasitoid taxa when some aspects of host/parasitoid biology are being Volume 1, Number 1, 1992 Tentative Composite Hypothesis ORUSSOMORPHA Stephanidae ,. Ichneumonidae (Troph, Vir) Braconldae (Troph, Terat, Vir) ACULEATA ,. Cynlpoidea (Troph, Vir) %*. Proctotrupoidea s.l. . Chalcidoidea '• Scelionoidea (Troph, Terat) Trigonalidae Megalyridae - Ceraphronoidea '• Evanioidea s.l. Lineage containing at least some endoparasitoids Fig. 5. Composite hypothesis of apocritan relationships, based largely on Rasnitsyn (1988) but modified based upon findings by Mason (unpublished), Gibson (1985), Johnson (1988) and Whitfield et al. (1989). Lineages marked as containing endoparasitoids may also contain (often among their basal clades) some ectoparasitoids. Troph - presence of a persistent trophamnion, at least through first instar, in at least some species. Terat - presence of some sort of teratocytes in at least some species. Vir - presence of some sort of associated viruses (that are introduced into host insects) in at least some species. Not all species in lineages marked with these abbreviations necessarily, nor are all occurences of a trophamnion, teratocytes or viruses assumed to be homologous. Apparent absence of a trophamnion, teratocytes, or viruses in a lineage may be simply due to lack of data in many cases. Both the tree and the distribution are offered to suggest groups in which further research would be especially helpful. discussed. Figure 5 shows the phylogenetic distri- bution of the presence of these features, as super- imposed upon a "composite cladogram" concocted from the hypothesis of Rasnitsyn (1988) combined with refinements by other concurrent and subse- quent research (e.g. Mason upublished, Gibson 1985, 1986, Johnson 1988, Whitfield et al. 1989). "Ichneumonomorpha " The ectoparasitoids found within basal lineages of both Ichneumonidae and Braconidae appear to fit the general groundplan biology in possessing paralyzing venoms for incapacitating hosts (the venom of Bracon being the best-studied example - see Beard 1978 and Piek 1986 for more details) and and rapid development of the larvae upon the usually moribund host. Within each of these two families some form of endoparasitoid habit has appeared several times (see Gauld 1988 for over- view; Shaw 1 983 and Whitfield, in press, provide a relatively well-studied example from the Braconidae). Within each of the two families a number of derived features associated with endo- parasitism have independently appeared in re- markably similar fashion - a prominent case being the existence of mutualistic viruses asociated with immune suppression of hosts in microgastrinae and chelonine and related braconids and in campoplegine and a few other ichneumonids. There is no real indication, however, that the ichneumonid-associated viruses and the braconid- associated viruses are particlularly closely related, let alone form a monophyletic group. Gauld (1988) has pointed out some differences betwen the two families in evolutionary trends in parasitism, especially in the host groups exploited and in what way they are utilized. An additional difference that appears from a review of the lit- erature is that many braconids possess teratocytes that influence the host/parasitoid relationship, whereas these are not known from Ichneumonidae. Nevertheless, I expect that this trend will be found to hold only at some level lower than the family level, since teratocytes appear to be absent from many endoparasitoid braconids and few ichneumonids have been intensively studied enough to rule out the existence of teratocytes during their development. In both families, but particularly in Ichneumonidae, some endoparasitoids of host pupae are found that apparently do not interact in a particularly active or long-term way with the host and show little biological similarity to the more derived larval endoparasitoids, as Gauld (1988) has pointed out. In this respect they are similar to the egg parasitoids found in other superfamilies. Despite the large gaps in our knowledge of comparative biology of Ichneumonoidea, this group is certainly biologically the best -known of major non- aculeate apocritan groups, at least in terms of the intimate details of host-parasitoid biology. Nevetheless, much of what is known has been studied in only a few taxa, e.g. Microgastrinae, Aphidiinae and Campopleginae. 10 Journal of Hymenoptera Research "Proctotrupomorpha" Within this infraorder true ectoparasitoids are found, to my knowledge, only within some groups of Chalcidoidea (especially some or many Chalcididae, Eurytomidae, Torymidae, Eupelmidae, Pteromalidae, Eulophidae and Elasmidae). A number of other groups within Chalcidoidea and Scelionoidea parasitize insect eggs and are not particularly highly derived in their adaptation to endoparasitism, although a few unique venom-associated substances and functions are known (Strand 1986). Nevertheless, the diver- sity in host/parasitoid biology within this infraorder is truly incredible, ranging from ecto-to endoparasitism, solitary to gregarious and poly- embryonic development, spanning a highly diverse array of host organisms; it is difficult to generalize about trends in the evolution of parasitism. Even within some large families such as Pteromalidae, Eulophidae and Encyrtidae, the diversity of lifestyles is bewildering. Although some detailed comparative work has been undertaken on egg parasitoids (especially Trichogramma and Scelionidae - e.g., see Strand 1986 and Strand and Wong 1 991 for some comparative review), the twin difficulties of poorly known biology (at least at the level of detailed host/ parasitoid interactions) and still unsatisfactory (but very rapidly improving) classification for many groups of "Procto- trupomorpha" have hindered comparative work. The potential for significant study of the evolution of parasitism in this infraorder is enormous A few generalizations can be made. Many of the ectoparasitoids within the Chalcidoidea appear to possess paralyzing venoms and exhibit rapid de- velopment within the host organism, as is the general plesiomorphic rule for apocritans. Some of the less derived endoparasitoids, such as the Ibaliidae in the Cynipoidea, appear to possess a final ectoparasitic feeding phase, which might be relatively plesiomorphic, as has been suspected in some braconid groups (Shaw and Huddleston 1991). Within the Chalcidoidea, Proctotrupoidea s.l. and Platygastridae some spectacular larval developmental modifications have evolved, the functions of which are not always understood, but a ppear to be characteristic of phylogenetic lineages. In general, the Proctotrupoidea as a group appear to be relatively less derived in their methods of endoparasitism, but details of their host/parasi- toid interactions are sketchy. The equally, if not even more, poorly-understood parasitic Cynipoidea sporadically exhibit some unusual features, such as mutualistic viruses analogous to those of Ichneumonoidea (Rizki and Rizki 1990), but too little is known of most species to generalize in any significant way about them. Table 1 provides some indication of how little we know currently of some aspects of proctotrupomorph host/parasitoid biology. "Evaniomorpha" As discussed above, recent research indicates that this infraorder from Rasnitsyn's (1988) classi- fication is probably not a monophyletic group. Hence, there is perhaps little reason to suspect it to have any biological coherence, even when it is better known biologically. Whatever similarities the Stephanidae and Megalyridae might have, for instance, in ectoparasitism of concealed xylopha- gous insects, are probably ancestral states shared with many other basal lineages of Apocrita. The only true endoparasitoids found within this group are within the Trigonalyidae, Ceraphronidae (but not the Megaspilidae) of the Ceraphronoidea, and the Aulacidae of the (possi- bly also not monophyletic) Evanioidea. The details of the host/parasitoid interaction in these endoparasitoid groups is extremely poorly known and they appear to have little in common with one another biologically. Other groups, such as the Evaniidae and Gasteruptiidae, are hardly parasi- toids at all, the former perhaps being better de- scribed as predators of cockroach eggs and the latter as consumers of solitary bee larval provisions (and sometimes also of bee larvae). It is possible that the largely hyperparasitic biology of the Trigonalyidae (reviewed by Weinstein and Austin 1991) could ease the difficulties of development of endoparasitoid life in this group, in that they often attack hosts whose immune systems have already been compromised by other parasitoids. No really complex host/parasitoid physiological phenomena have been described in this complex of Hym- enoptera, but so little is known that the discovery of such phenomena would not be surprising. FUTURE RESEARCH The above brief survey of apocritan parasitoid biology is not a complete review of the subject. The interested reader is referred instead to the more Volume 1, Number 1, 1992 11 Table 1. Taxonomic distribution of some "tools" used by endoparasitoids in interactions with host insects. Refer to text for further explanation (especially for those portions of the table where question marks appear). Although space does not permit an exhaustive listing of supportive references here, most sources of information are cited in the text; where essentially nothing is known, a "?" appears; where conflicting or inconclusive reports are available, a "+?" or "-1" appears. Trophamnion Teratocytes Viruses Ichneumonomorpha Ichneumonidae Braconidae Proctotrupomorpha + (some) + (some) + (some) Cynipoidea "Proctotrupoidea" Chalcidoidea Scelionoidea (some) Evaniomorpha Megalyroidea Trigonalidae Ceraphronoidea Evanioidea ? _ 7 comprehensive treatments of Clausen (1940), Askew (1971), Fisher (1971), Vinson and Iwantsch 1980a,b, Thompson (1983), Beckage (1985), Lawrence (1986), Slansky (1986), Stoltz (1986), Gauld and Bolton (1988), Coudron (1990) and Thompson (1990). This review is offered more as a stimulant to further comparative work on parasi- toid biology, using the phylogeny of the groups, as far as is known, as a guide. I hope to have dem- onstrated some areas and groups where further information is most needed, but there really are no biologically well-known higher taxa represented here. Recent developments in physiology, molecu- lar genetics, immunology, cell culture and many other areas now make some aspects of comparative parasitoid biology approachable for the first time. The potential of the parasitic Hymenoptera, both as biological systems for the study of parasitism and as subjects of evolutionary reserach, has still barely been tapped, relative to the wealth of in- formation that lies yet undiscovered. ACKNOWLEDGMENTS I would like to thank, first of all, Andy Austin and Denis Brothers for asking me to contribute the talk upon which this paper is based to the Hymenoptera Phylogeny Symposium which they moderated at the International Society of Hymenopterists Meeting in Sheffield in August 1991 . Feedback and information received there from numerous members of the audience greatly enhanced the written version. I would also like to thank the following individuals for contributing valuable discussion of various ideas contained in this paper, and /or for reading the manuscript: Andy Austin, Denis Brothers, Sydney Cameron, Dan Gerling, John Noyes, Norm Johnson, John LaSalle, Bill Mason, Mike Sharkey, Mark Shaw, Don Stoltz and Bob Wharton. Some of the support for my own studies, especially of polydnaviruses, has been provided by the National Science Foundation under grant BSR - 9111938. LITERATURE CITED Askew, R.R. 1971. Parasitic Insects. American Elsevier, N.Y. Askew, R.R. and M. R. Shaw. 1986. Parasitoid communities: their size, structure and development, pp. 225-264. In Waage, J. and D. Greathead, eds., Insect Parasitoids, Symposium of the Royal Entomological Society of London 13. Academic Press, London. Beard, R.L. 1 978. Venoms of Braconidae, pp. 773-800. 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The host relationships of trigonalyid wasps (Hymenoptera: Trigonalyidae), with a review of their biology and catalogue to world species. Journal of Natural History 25: 399-433. Whitfield, J.B. 1990. Parasitoids, polydnaviruses and endosymbiosis. Parasitology Today 6: 381-384. Whitfield, J.B. In press. The polyphyletic evolution of endoparasitism in the cyclostome lineages of Braconidae (Hymenoptera). Systematic Entomology. Whitfield, J.B., N.F.Johnson and M.R. Hamerski. 1989. Identity and phylogenetic significance of the metapostnotum in non-aculeate Hymenoptera. Annals of the Entomological Society of America 82: 663-673. J. HYM. RES. 1(1), 1992 pp. 15-24 Cladistics of the Ichneumonoidea (Hymenoptera) Michael J. Sharkey and David B. Wahl (MJS) Biological Resources Division, CLBRR, Agriculture Canada, Ottawa, Ontario, K1A 0C6, Canada; (DBW) American Entomological Institute, 3005 SW 56th St., Gainesville, Florida, 32608, U.S.A. Abstract . — We recognize only two extant families, Ichneumonidae and Braconidae, in the Ichneumonoidea. All other recent taxa that have been regarded as family- level taxa can be reasonably placed within one or the other family. We find no evidence to place Praeichneumonidae in the Ichneumonoidea and therefore consider it incertae sedis in the Apocrita. Likewise, though it is an ichneumonoid, there are no synapomorphies which suggest that Tanychora is an ichneumonid. The cladograms of fossil and recent ichneumonoids support the monophyly of Eoichneumonidae and a sister-group relationship with Braconidae. The purpose of this paper is to review and revise the family-level cladistics and classification of the Ichneumonoidea. The families comprising the Ichneumonoidea have fluctuated considerably over the years and recent classifications have included from two to seven extant families, i.e., from only Braconidae and Ichneumonidae, (e.g., Gauld and Bolton, 1988) to various combinations of the following: Agriotypidae (e.g., Mason 1971); Aphidiidae (e.g., Tobias 1989; Mackauer 1968; Mackauer and Stary 1967; Stary 1966; Conca 1973); Apozygidae, (Mason 1978); Braconidae; Ichneu- monidae; Megalyridae (Pagliano and Scara- mozzino, 1990); and Paxylommatidae (e.g., Achterberg 1976a; Mason 1981). We examine the validity of these familial concepts from a cladistic perspective and recognize a classification that consists of only two families, Braconidae and Ichneumonidae. PLACEMENT OF THE ICHNEUMONOIDEA WITHIN HYMENOPTERA Rasnitsyn (1988) suggested that Aculeata (his Vespomorpha) is the sister-group of Ichneumonoidea on the basis of the shared possession of an apomorphic condition of the propodeal foramen and the presence of valvilli in the ovipositor (Gauld 1 976; originally referred to as hemmplattchen by Oeser 1961). The propodeal foramen, into which the metasoma is inserted (Fig. 1), is narrow and subdivided by a pair of tooth-like condyli (the "propodeal teeth"). Zessin (1985) suggested that the Ichneu- monoidea is the sister-group of the remaining Apocrita. He based the monophyly of the Apocrita exclusive of the Ichneumonoidea on the loss of the anal veins, 2A and a, of the fore wing. In Zessin's phraseology, all traces of the lanceolate cell (anal) are lost. Within the Apocrita, traces of the lanceolate cell, in the form of 2A and crossvein a, are found only in some Braconidae. Although he did note that the veins must be convergently lost in the Ichneumonidae and the 'remainder of the Apocrita', Zessin did not consider the fact that they could be a reversal, an equally parsimonious interpretation. A third hypothesis was presented by Rasnitsyn (1980) and supported by Johnson (1988). This is that Ichneumonoidea, Chalcidoidea, Cynipoidea, and Proctotrupoidea s.l. (excluding Cera- phronoidea) are a monophyletic group, the Ichneumonomorpha. Johnson supported the Ichneumonomorpha on the basis of the apomorphic condition of the midcoxal articulations, i.e., a reduced basicoxite, a deep coxal groove, and laterally displaced coxal cavities. According to Johnson, an identical character occurs in several lineages of Aculeata. A total of six steps accounts for the distribution of the character, with one derivation in Ichneumonomorpha, and four derivations and one reversal in Aculeata. If, however, one considers the Ichneumonoidea to be the sister-group of the Aculeata, the number of steps is the same for a clade consisting of Ichneumonoidea, Aculeata, Cynipoidea, Chalcidoidea, and Proctotrupoidea (using the 16 Journal of Hymenoptera Research Fig. 1. Alabagrus texanus, posterior view of mesosoma with legs and metasoma removed. Arrow indicates the propodeal teeth in the propodeal foramen. cladogram of Aculeate family relationships given in Johnson's figure 35). Taking all the evidence into consideration, i.e. coxal articulations, wing venation, valvilli, and propodeal teeth, the sister-group relationship with the Aculeata is the most parsimonious hypothesis. MONOPHYLY OF THE ICHNEUMONOIDEA Character polarity for our cladistic analysis (Maddison et al., 1984) was based on the following sequential ordering of outgroups: Aculeata, other Apocrita, Orussidae, Xiphydriidae, other Symphyta (Gibson 1985, Rasnitsyn 1988). It is based on the distribution of character states in these outgroups that we suggest the following autapomorphies for the Ichneumonoidea. 1 . Adult mandible with two teeth (Mason 1987). The plesiomorphic condition is three or perhaps four mandibular teeth, as in almost all Symphyta, and the vast majority of Apocrita. Some derived lineages of Chalcidoidea, Cynipoidea, Proctotrupoidea, and Scelionoidea have two teeth, but based on our surveys the ground plan of all of these taxa appears to be three or more teeth. Within the Ichneumonoidea, the teeth have been reduced to one in some lineages. In Alysiinae, and some Opiinae the number has been increased to three or four. In Ichneumonidae the upper tooth has become subdivided in Diplazontinae and certain Banchini. 2. Prepectus fused to posterior lateral (vertical) margin of the pronotum, mesothoracic spiracle positioned directly above prepectus, and external pit indicating origin of spiracular occlusor muscle lying near posterior pronotal margin (Gibson, 1 985) . 3. Sternum of first metasomal segment divided into heavily sclerotized anterior section and comparatively weakly sclerotized posterior section (Mason 1981, 1987). This character is found only in Ichneumonoidea. 4. Metasomal segments 1 and 2 articulated by a pair of dorsolateral condyles on the hind margin of tergum 1 and anterior margin of tergum 2. This character is found only in Ichneumonoidea (Mason 1987). The plesiomorphic condition is that metasomal segments 1 and 2 do not articulate on dorsolateral condyles so that they can telescope; such telescoping is not possible in ichneumonoids. In some other Apocrita this telescoping ability may be lost due to partial or complete fusion. 5. Costa and radius of fore wing adjacent/ appressed, such that the width of the costal cell is narrower than the costal vein (Fig. 2). In many ichneumonoid taxa the costal cell is completely absent. Convergent appearances of this character are found in other Apocrita, most notably Rhopalosomatidae and miscellaneous Larridae. 6. Vein 2r-m of fore wing absent. The identity of the veins making up the apparent r-m cross veins of the fore wing has been a matter of some dispute. One interpretation is described by Tobias and Belokobylski (1984), with Braconidae possessing 2- Rs and 2r-m (3r-m is lost) and Ichneumonidae possessing 2r-m and 3r-m (2-Rs is lost). Much of the argument of the these authors was based upon instances of aberrant venation in braconids. Rasnitsyn (1980) was of the opinion that 2r-m was lost (2-Rs and 3r-m retained) in an ancestral ichneumonoid and we have adopted this interpretation as it best accounts for venation in fossil taxa. For example, in the Cretaceous ichneumonoid Tanychora (Fig. 3) the outermost r- m crossvein is well distad 2m- cu, the usual position for 3r-m in Hymenoptera, and 2-Rs is in the plesiomorphic basal position. In the instances of 2m-cu occurring in braconids cited by Tobias and Belokobylski (Fig. 4), the outermost vein is in the same position. Rather than posit a migration of 2r- m from its usual position between lm-cu and 2m- cu, Rasnitsyn's suggestion seems simpler. Rs is therefore considered to have migrated apically in Volume 1, Number 1, 1992 17 Fig. 2. Ichneumonidae sp., fore and hind wing. B = basal hamuli, A = apical hamuli C = costa v\V\v*N^<* Figs. 3, 4. 3, Tanychora petiolata, fore wing. 4, Ontsira rara, fore wing. Ichneumonidae to form the family's characteristic areolet (Fig. 2). 7. Larva with hypostomal spur. Ichneumonoid larvae possess an extensive system of sclerotized bands around the mouthparts. The hypostoma is a sclerotized band running posteriorly along the subgenal margin of the cranium; a spur projects ventrally from the hypostoma across the stipes (Fig. 5). The hypostomal spur is found only in Ichneumonoidea and apparently functions to help brace the labium during cocoon construction. It has been lost on several occasions in braconids and ichneumonids, usually in taxa that do not spin cocoons (Short, 1978). TAXA THAT HAVE BEEN RECOGNIZED AS FAMILIES OF ICHNEUMONOIDEA Agriotypus This group is usually recognized as an ichneumonid subfamily by ichneumonid researchers e.g., Townes (1969). Agriotypus shares the two known autapomorphies of Ichneumonidae, the apical displacement of vein 2-Rs of the fore wing with the resulting formation of the characteristic ichneumonid areolet, and loss of vein 1 -Rs+M of the fore wing. We keep Agriotypus within Ichneumonidae. Aphidiinae It is now fairly well accepted that Aphidiinae are derived braconids sharing all of the braconid synapomorphies (detailed below). The character that has caused some confusion in the group's placement is the presence of an apparent suture between metasomal terga 2 and 3. When examined carefully, this is found to be a weakness in the fused terga rather than a true suture. Therefore, the braconid synapomorphy of fused terga 2 and 3 is valid even with the inclusion of Aphidiinae. Some specialists, particularly Tobias (1968, 1989) and Tobias and Stary (in the 1988 edition of the newsletter Ichnews) maintain that Aphidiinae should have familial status. Tobias (1989) stated that there are two well established lineages within the Braconidae, the cyclostomes (Apozyginae, Alysiinae, Braconinae, Doryctinae, Gnam- ptodontinae, Opiinae and Rogadinae s.l.) and the clade of endoparasitoids representing all other braconids. To date there as has been no compelling evidence to associate the Aphidiinae with either of these lineages, and on the basis of this negative evidence, Tobias (1968, 1989) argued that Aphidiinae should be considered the sister-group of the Draconids. In our view, this is faulty logic. If, as Tobias and Stary appear to believe, the cyclostome braconids, the Aphidiinae and the non- cyclostome braconids form an unresolved trichotomy, the Aphidiinae could represent the sister-group of either or both of the two other taxa. There are synapomorphies defining the Braconidae 18 Journal of Hymenoptera Research Figs. 5-6. 5, Grotea sp., head capsule. H = hypostoma, HS = hypostomal spur, M = mandible, S = stipital sclerite. 6, Aleiodes terminalis, head. C = clypeus, L = labrum including the Aphidiinae, but when one excludes the Aphidiinae there is none. This is sufficient reason to classify the Aphidiinae within the Braconidae. Apozyx Apozyx is represented by one species known only from Chile.Mason(1978) described the species and proposed family rank in the Ichneumonoidea. It has also been included as a subfamily of the Braconidae (e.g., Quicke and Achterberg, 1990) Apozyx shares all four synapomorphies of the Braconidae, i.e., migration of vein lr-m to or basal to the separation of veins Rl and Rs in the hind wing, loss of functional basal hamuli, loss of stub of vein C of the hind wing basad the distal hamuli, and fusion of metasomal terga 2 and 3. In our view, Apozyx is a cyclostome braconid. The most telling synapomorphy supporting this hypothesis is that the labrum is the typical cyclostome type: concave, triangular, smooth, and mostly glabrous (cf. Fig. 6) and the ventral margin of the clypeus is concave (Fig. 6). Apozyx may be the sister-group of the remaining cyclostomes, all of which have lost the second abscissa of vein Cu (2-Cu) of the hind wing (Fig. 8). The only character which argues against this placement is the apparently plesiomorphic presence of vein 2m-cu in the fore wing of Apozyx (Fig. 8). This vein is present in the Ichneumonidae and other outgroups but present in no other Braconidae except some freak specimens, e.g. Ontsira rara (Fig. 4) (Tobias and Belokobylskij, 1984). It is more parsimonious to hypothesize a recurrence of 2m- cu in Apozyx than treat the cyclostome characters as convergences. Braconidae (including Aphidiinae and Apozyx) This is one of the two families we recognize in Ichneumonoidea. The family is supported by four autapomorphies. The first autapomorphy, the fusion of metasomal terga 2 and 3, is found without exception in all known braconids. It is also found convergently in derived lineages of Ichneumonidae and Aculeata, but, based on its distribution within these taxa, the plesiomorphic condition of mutually articulating terga must be considered to be part of the ichneumonoid and aculeate ground plan. The second autapomorphy is the loss of functional basal hamuli on vein C of the hind wing. Functional basal hamuli are hooked and are found near the point where veins C and R of the hind wing diverge (Fig. 2). Basal hamuli are found in some members of the Braconidae, e.g., Braconinae (Fig. 7), but they do not form hooks and do not appear to function as wing couplers. Functional basal hamuli are widespread in Ichneumonidae (Fig. 2), Aculeata, Trigonalidae and the symphytan superfamilies, but are unknown in the Braconidae. It is worth noting here that the convergent loss of functional basal hamuli in the Apocrita exclusive of the Ichneumonoidea, Aculeata and Trigo- nalyidae, may be a synapomorphy for this assemblage. This suggestion is supported by several venational characters such as the loss of the second closed Rs cell in the fore wing and the loss of a closed Cu cell in the hind wing. A third autapomorphy of Braconidae is the loss of an independent stub of vein C of the hind wing, basad the distal hamuli (Fig. 7). Vein C is complete in some Aculeata and presumably the ground plan for the group (Brothers, 1975). Many aculeate taxa have some indication of vein C basad the point Volume 1, Number 1, 1992 19 where R or Rl meets the anterior wing margin. Although vein C of the hind wing is incomplete in all Ichneumonoidea, most Ichneumonidae have retained a small stub of vein C basad the point where Rl meets the anterior margin (Fig. 2) and this is the most parsimonious assignment for the ground plan. The fourth braconid autapomorphy is the basal migration of vein lr-m of the hind wing, to or basal to the separation of veins Rl and Rs (Fig. 7); the plesiomorphic condition is for lr-m to be apicad the separation. Ichneumonidae, Aculeata, other Apocrita, e.g. Trigonalyidae, and most Symphyta have this plesiomorphic state. In at least one ichneumonid taxon (Neorhacodes) lr-m is opposite the Rl-Rs separation, but never basad. There are several braconid taxa such as Trachypetus and Rhamphobarcon where reversals have occurred. Mason (1981 ) discussed the various positions of the r-m crossveins in ichneumonoids. He posited the ancestral ichneumonoid to have two r-m crossveins with Ichneumonidae having lost lr-m and Braconidae having lost 2r- m. We reject Mason's arguments because explicit outgroup analysis exposes them as unsupported. With rather convincing support, Gibson (1985) postulated the following pattern of relationships: (Siricidae (Xiphydriidae (Orussidae + Apocrita))). We are unaware of any Apocrita with two r-m crossveins, with the exception of some braconids. Furthermore, the one crossvein present in apocritans is always opposite or distad the point of separation of Rl and Rs, with the aforementioned exception of braconids (Gauld, 1984). Orussids have only one crossvein, which is distad of the separation by about the length of the crossvein. Xiphydriids have three crossveins: r-m and 3r-m are tubular, 2r-m is spectral. It is noteworthy that 1 r-m is well distad of the Rl and Rs separation and in the same position as the lr-m crossvein of ichneumonids and aculeates. There are two r-m crossveins in the siricid hind wing: the most basal varies from basad to distad the separation, and the outermost one is in the position of 3r-m of xiphydriids and the Jurassic siricoid Protosirex (Mason, 1981 : Fig. 5). No trace of a crossvein can be seen between the two existing crossveins. We therefore conclude that the most parsimonious solution to the question of hind wing r-m homologies is to consider: (1) 2r-m and 3r-m to be lost in the common ancestor of Apocrita + Orussidae, (2) lr-m to be shifted in braconids to a position basad the separation of Rl and Rs, and (3) the second r-m crossvein of some braconid Figs. 7-8. 7, Coeloides rufovarigatum, hind wing. B = basal hamuli, S = elongate setae. 8, Apozyx penyai, fore and hind wing. subfamilies to be the product of one or more reversals. The preceding hypothesis prevents the wildly unparsimonious scenario of multiple 2r-m losses. Ichneumonidae (including Agriolypus and Paxylommatinae) Ichneumonids are usually recognized by having 1-Rs+M absent and metasomal terga 2 and 3 articulating. The former character is apomorphic though it is also found in widely scattered groups of braconids; the latter is plesiomorphic. What other apomorphies distinguish the family? Mason believed that ichneumonids lack lr- m in the hind wing; our objections to that hypothesis are detailed above in the discussion of Braconidae. Tobias and Belokobylski (1984) argued that the areolet in braconids and ichneumonids is formed by different veins (2-Rs and 2r-m in braconids, 2r-m and 3r-m in ichneumonids). Again, our objections to that idea are presented in the section dealing with ichneumonoid autapomorphies. Ichneumonidae have a very characteristic, small, areolet (Fig. 2). If our hypotheses on fore wing vein homologies are correct, then the apical displacement of vein 2-Rs is 20 Journal of Hymenoptera Research necessary to account for the small areolet. A precursor condition to this may be the long and slanting vein 2-Rs of Tanychora (Fig. 3), but this is quite speculative. In summary, we put forward the loss of fore wing vein 1-Rs+M, and the apical displacement of fore wing vein 2-Rs as autapomorphies of the Ichneumonidae. Megalyridae Pagliano and Scaramozzino (1990) include this family in the Ichneumonoidea in their catalog of hymenopteran generic names. This is a rather novel hypothesis which we reject since megalyrids lack the ichneumonoid synapomorphies discussed previously. Paxylommatinae This taxon consists of two extant genera, Hybrizon Fallen and Ghilaromma Tobias. Paxy- lommatinae has been treated as a subfamily of Braconidae (Shenefelt 1969; Achterberg 1976 a,b), a separate family (Tobias 1968; Marsh 1971, 1979; Mason 1981; Achterberg 1984), and a subfamily of Ichneumonidae (Rasnitsyn 1980; Gauld 1984; Gauld and Bolton, 1988). Paxylommatinae has been placed in the Braconidae on the basis of the absence of vein 2m- cu in the fore wing. The large number of autapomorphies has led to its recognition as an independent family. Mason (1981) was the first to examine Hybrizon's relationship to Ichneumonidae and Braconidae from a phylogenetic perspective. He demonstrated that metasomal terga 2 and 3 are not fused, thus excluding Hybrizon from the Braconidae. Further evidence of this is that 2m-cu of the fore wing appears to be part of the paxylommatine ground plan, as demonstrated by the fossil paxylommatine Tobiastes striatus from Baltic amber (Fig. 9) (Kasparyan 1988). On the basis of his ideas on hind wing r-m homologies, Mason (1981) suggested that the r-m crossvein of Hybrizon is 1 r-m and eliminated the genus from membership in the Ichneumonidae. As discussed earlier under the section on Ichneumonidae, we reject this interpretation. Achterberg (1984) hypothesized Paxy- lommatinae to be the sister-group of Ichneumonidae, citing as evidence the absence of vein 1-Rs+M in the fore wing, and loss of vein lr- m in the hind wing. In turn, this assemblage was considered to be the sister-group of Braconidae. We agree that Paxylommatinae and Ichneumonidae are closely related, although we disagree with the interpretation of hind wing venation for reasons Figs. 9-10. 9, Tobiasites striatus, fore wing. 10, Hybrizon flavocinctum, fore wing. presented above. Achterberg gives four autapomorphies supporting the monophyly of Paxylommatinae but only one character for Ichneumonidae exclusive of Paxylommatinae — the presence of an accessory longitudinal tracheal commissure. This may be a good autapomorphy for ichneumonids, although more taxa need to be surveyed. The main criticism of his use of the character is that the larval stages of members of Paxylommatinae have never been described. How can one differentiate between two groups when the critical character for one of them is unknown? Achterberg's argument for the sister-group relationship of Paxylommatinae and Ichneu- monidae appears unsupported. Members of Paxylommatinae (Fig. 10) lack vein 1-Rs+M, as do all ichneumonids. At present, this is the strongest direct evidence placing it in the Ichneumonidae although the reliability of the character is somewhat vitiated by its multiple losses in Braconidae. As mentioned earlier, Rasnitsyn pointed out the similarity of Hybrizon's venation to that of Neorhacodes. Members of both genera parasitize aculeate Hymenoptera, and they may well be sister-groups. Stephanidae The Stephanidae have often been included within Ichneumonoidea (Townes 1969; Carlson 1979). Townes (1969) based the superfamily Ichneumonoidea on: a) distinct vein C of the fore wing, b) veins C and R of the fore wing adjacent or Volume 1, Number 1, 1992 21 fused so there is no costal cell between them, c) antenna with more than 14 flagellomeres, and d) adult mandible with two teeth. We reject these arguments for the following reasons. Vein C is absent in Stephanidae, and even if it were present the presence of vein C is plesiomorphic. Contrary to ichneumonoids, stephanids possess a narrow but distinct costal cell anterad vein R. The polarity of the character state, antenna with more than 14 flagellomeres, is uncertain and quite possibly plesiomorphic. Finally, stephanid adults have only one apical mandibular tooth not two. Within the context of the characters analyzed here, the propodeal teeth and valvilli discussed in section one are absent in stephanids and they possess only one of the ichneumonoid apomorphies discussed earlier, the loss of vein 2r-m of the fore wing. This convergent loss is found in all of the larger apocritan lineages and therefore is not particularly convincing. Thus, there appears to be little evidence to support the placement of the Stephanidae in the Ichneumonoidea. FOSSIL ICHNEUMONOIDEA Rasnitsyn (1983) described Praeichneumon townesi as a new family (Praeichneumonidae) in Ichneumonoidea; the specimen is from Lower Cretaceous deposits in Mongolia. Placement in the Ichneumonoidea was based on a narrow costal cell of the fore wing, an external ovipositor, and an antenna with more than 13 flagellomeres (Rasnitsyn 1983; Rasnitsyn and Sharkey 1988). Examination of Rasnitsyn's figures (Rasnitsyn, ibid.) reveals a distinct costal cell, unlike the condition in other ichneumonoids where the costal cell is narrower than the costal vein. An external ovipositor is a plesiomorphic character state for the Apocrita and of no value for determining relationships at this level of investigation. Numerous flagellomeres might be a ground plan character state for the Apocrita because it is present in several taxa that appear to be basal in the Apocrita based on characters such as venation, e.g., Trigonalyidae, Stephanidae. Finally, Praeichneumon has vein 2r-m present in the fore wing, a vein that all ichneumonoids have lost (see above discussion). The lack of the critical ichneumonoid synapomorphies listed at the beginning of this essay leads us to remove this species from Ichneumonoidea and consider it incertae sedis within the Apocrita. Several other fossil Hymenoptera are of interest. Townes (1973) described Tanychora from the lower Cretaceous of Transbaikalia. He placed it in the Ichneumonidae, stating that the genus could be "ancestral to all of the modern Ichneumonidae, it could represent an extinct phyletic line, or it could be a primitive representative of 1 of the modern subfamilies. There is not sufficient evidence to eliminate any of these 3 possibilities." Rasnitsyn (1980) placed Tanychora in its own subfamily (Tanychorinae) in the Ichneumonidae. Eoichneumon was described from a specimen of the early Cretaceous of Australia (Jell and Duncan 1986) and the family Eoichneumonidae was proposed for the genus. Rasnitsyn and Sharkey (1988) described an additional three genera and 14 species (Baissobracon (1 species), Cretobraconus (7 species), Archobraconus (6 species)) in Eoich- neumonidae. These species are from the early Cretaceous of Siberia and Mongolia. The above fossil genera were defined by combinations of plesiomorphic and apomorphic characters, and hence their status and relationships are uncertain. We have compiled a data matrix using Townes (1973) and Rasnitsyn and Sharkey (1988) as sources of characters. The set of available characters is quite small since few characters are visible in fossil impressions. Ovipositor length and length of 1-Rs of the fore wing were used by Rasnitsyn and Sharkey, but these characters are not employed here because of their variable nature, lack of polarity, and our inability to code the ground- plan for the Ichneumonidae and Braconidae. The characters, polarized using the same outgroups as those used to support the monophyly of the Ichneumonoidea, are as follows; the data matrix is given in Table 1. 1. Fore wing vein 1-Rs+M 0: present 1: absent. 2. Fore wing vein lcu-a 0: apicad vein 1-M 1: basad vein 1-M. 3. Fore wing vein 2-Rs 0: basal position (basad apex of stigma) 1: apical position (apicad apex of stigma). 4. Fore wing vein 3r-m 0: tubular 1: spectral/absent. 5. Fore wing vein 2m-cu. 0: tubular 1: spectral/absent. 6. Hind wing vein lr-m. 0: apicad separation of veins Rs and Rl 22 Journal of Hymenoptera Research 1 : at or basal to separation of Rs and Rl . (The hind wing is missing in Eoichneumon.) 7. Notauli of mesoscutum. 0: separated for their entire length 1: converging before scutellum. (The mesoscutal surface cannot be seen in Baissobracon .) 8. Surface of propodeum. 0: areolate 1: finely reticulate. 9. Metasomal terga 2-3. 0: articulated 1: fused. 10. Metasomal terga 1-2. 0: without prominent longitudinal striae. 1: with prominent longitudinal striae. The relationships among Ichneumonidae, Braconidae, Tanychora, Eoichneumon, Baissobracon, Cretobracomts, and Archobraconus were analyzed using the Hennig86 cladistics program (version 1.5) of Farris (1988). The ie (implicit enumeration) option resulted in four cladograms. One of the cladograms was supported only by an ambiguous optimization and was rejected (Platnick et al. 1991 ). The remaining cladograms (Fig. 1 1 ) had a length of 11 steps, a consistency index of 0.83 (excluding autapomorphies), and a retention index of 0.85. Some characters used in the analysis, especially loss or weakness in veins, may be difficult to determine in fossil specimens due to poor preservation or variable impression. Therefore, some of the conclusions that follow, particularly those concerning the monophyly of the Eoichneumonidae, are rather speculative. Our conclusions are: 1 ) The cladograms support the monophyly of the Eoichneumonidae based on the reduction or absence of fore wing crossvein 3r- m. 2) The clade Eoichneumonidae plus Braconidae is supported by the loss or reduction of fore wing crossvein 2m-cu. 3) The inclusion of Tanychora in the Ichneumonidae or any other family may not be inferred from the data and therefore we consider it as a plesion in the Ichneumonoidea. Wiley (1981) discusses the problems of classifying fossil taxa of uncertain placement, using the convention of incertae sedis and the plesion concept. Wiley defines the latter (p. 205), modified from the original concept of Patterson and Rosen ( 1 977), as "a name of variable rank accorded a fossil species . . . when classified with one or more Recent species or groups." Wiley goes on to say (p. 219) that "the use of 'plesion' is a conservative means of classifying fossils with Recent taxa ... no matter how many times the plesion's phylogenetic position may change in relation to its Recent relatives." Table 1. Data set of extinct and extant ichneumonoid taxa (characters described in the text). Taxa Characters 1 2 3 4 5 6 7 8 9 10 outgroup Ichneumonidae 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Tanychora Baissobracon 0 0 0 1 0 0 0 1 0 1 0 0 0 ? 0 1 0 0 0 1 Cretobraconus 0 0 0 1 1 0 1 0 0 0 Eoichneumon 0 0 0 1 1 ? 0 0 0 0 Archobraconus 0 0 0 1 1 1 1 0 0 0 Braconidae 0 0 0 0 1 1 0 0 1 0 Thus, applying Wiley's sequencing convention, a classification of extant and fossil taxa that are considered Ichneumonoidea is as follows: Superfamily Ichneumonoidea incertae sedis: Plesion Tanychora Family Ichneumonidae Family Braconidae Family Eoichneumonidae ACKNOWLEDGMENTS Thanks to F. Ronquist, J.F. Landry, W.R.M. Mason, I. Gauld and an anonymous reviewer. S. Rigby and B. Flahey did the line drawings. G.A.P. Gibson directed us to the article by Zessin. LITERATURE CITED Achterberg, C. 1976a. Hybrizontinae or Hybrizontidae? (Hymenoptera Ichneumonoidea). Entomologische Berichten 36:61-64. Achterberg, C. 1976b. A preliminary key to the subfamilies of the Braconidae (Hymenoptera). Tijdschrift voor Entomologie 119:33-78. Achterberg, C. 1984. Essay on the phylogeny of the Braconidae (Hymenoptera: Ichneumonoidea). Zoologische Mede- delingen 57: 339-355. Brothers, D.J. 1975. Phylogeny and classification of the Aculeate Hymenoptera with special reference to the Mutillidae. University of Kansas Science Bulletin 50: 483-648. Carlson, R.W. 1979. Family Stephanidae, pp. 740-742. In Krombein, K. V., P.D. Hurd, D.R. Smith, and B.D. Burks, eds., Catalog of Hymenoptera in America North of Mexico, Vol. 1, Smithsonian Institution Press, Washington, D.C. 1198 pp. Conca, R.C., 1973. La familia Aphidiidae (Ins. Him.) en Espana. Caja de Ahorros y Monte de Piedad de Valencia. 312 pp. Farris, S.J. 1988. Hennig86 reference: documentation for version 1.5. Port Jefferson Station, New York. Gauld, l.D. 1976. The classification of the Anomaloninae (Hymenoptera: Ichneumonidae). Bulletin of the British Volume 1, Number 1, 1992 23 1 3 I I Ichneumon idae -Tanychora 6 9 -0—4 — Braconidae + -Eoichneumon 1 3 I I Ichneumonidae -Tanychora + 2 8 10 -J — I— I — Ba i ssobracon -Cretobraconus — | — Archobraconus 6 9 -jl I Braconidae B -Eoichneumon 2 8 10 III — Ba i ssobracon + Cretobraconus — j|— Archobraconus 1 3 -I — I— Ichneumonidae -Tanychora 9 5 6 ++ Braconidae •Eoichneumon -Archobraconus 2 8 10 6 I I I — I— Baissobracon Hh -Cretobraconus Fig. 11. A-C are the three minimum length cladograms from the data set of extinct and recent ichneumonoid taxa (Table 1), character descriptions are presented in the text. Black bars = apomorphies, grey bars = parallelisms, white bars = reversals Museum (Natural HistoryXEntomology) 33: 1-135. Gauld, I.D. 1984. An Introduction to the Ichneumonidae of Australia. British Museum (Natural History), London, 413 Gauld, I.D. and B. Bolton. 1988. The Hymenoptera . British Museum (Natural History) and Oxford University Press, Oxford, 332 pp. Gibson, G.A.P. 1985. Some pro- and mesothoracic structures important for phylogenetic analysis of Hymenoptera, with a review of terms used for the structures. Canadian Entomologist 117: 1395-1443. Jell, P. A. and P.M. Duncan, 1986. Invertebrates, mainly insects, from the freshwater, Lower Cretaceous, Koonwarra Fossil Bed (Korumburra Group), South Gippsland, Victoria. Memoir of the Association of Australasian Palaeontologists 3: 111-205. Johnson, N.F. 1988. Midcoxal articulations and the phylogeny of the order Hymenoptera. Annals of the Entomological Society of America 81: 870-881. Kasparyan, D.R. 1988. A new taxa of fam. Payxlommatidae (Hymenoptera, Ichneumonoidea) from the Baltic Amber. Academy of Sciences of the USSR 70: 3-134. [in Russian]. Mackauer, M. 1968. Aphidiidae, pp.1 -103. In Ferriere,Ch. and J. van der Vecht, eds. Hymenovterorum Catalogus (nov. ed.). Dr. W. Junk N.V., 's-Gravenhage. Mackauer, M. and P. Stary. 1967. World Aphidiidae, Hym. 24 Journal of Hymenoptera Research Ichneumonoidea. The Index of Entomophagous Insects. Le Francois, Paris. 193 pp. Maddison, W.P., M.J. Donoghue and D. R. Maddison. 1984. Outgroup analysis and parsimony. Systematic Zoology 33: 83-103. Marsh, P.M. 1971. Keys to the Nearctic genera of the Families Braconidae, Aphidiidae and Hybrizontidae (Hymenoptera). Annals of the Entomological Society of America 64: 841-850. Marsh, P.M. 1979. Family Hybrizontidae, p. 313. In Krombein, K.V., P.D. Hurd, D.R. Smith, and B.D. Burks, eds., Catalog of Hymenoptera in America North of Mexico. Vol. 1, Smithsonian Institution Press, Washington, D.C. 1198 pp. Mason, W.R.M. 1971. An Indian Agriotypus (Hymenoptera: Agriotypidae). Canadian Entomologist 103: 1521-1524. Mason, W.R.M. 1978. A new genus, species and family of Hymenoptera (Ichneumonoidea) from Chile. Proceedings of the Entomological Society of Washington 80: 606-610. Mason, W.R.M. 1981. Paxylommatidae: the correct family- group name for Hybrizon Fallen (Hymenoptera: Ichneumonoidea), with figures of unusual antennal sensiUa.Proceedingsof the Entomological Society of Washington 113:433-439. Mason, W.R.M. 1987. Discovery of female Apozyx (Hymenoptera: Apozygidae) and comments on its phylogenetic position. Proceedings of the Entomological Society of Washington 89: 226-229. Oeser, R. 1961. Ovipositor der Hymenopteren, IV. Vergleichende Untersuchyngen ueber die Teile des Ovipositors. Mitteilungen aus dem Zoologischen Museum in Berlin 37: 46-62. Pagliano, G and P. Scaramozzino, 1990 (1989). Elenco dei generi di Hymenoptera del mondo. Memorie Delia Societa Entomologica Italiana 122: 1 - 210. Patterson, C. and D.E. Rosen, 1977. Review of ichthyodectiform and other Mesozoic teleost fishes and the theory and practice of classifying fossils. Bulletin of the American Museum of Natural History 158: 81-172. Platnick, N.I., C.E. Griswold^ and J.A. Coddington. 1991. On missing entries in cladistic analysis. Cladistics 7: 337-343. Quicke, D.L.J, and C. van Achterberg. 1990. Phylogeny of the subfamilies of the family Braconidae (Hymenoptera: Ichneumonoidea). Zoologische V erhandelingerx 258, 95 pp. Rasnitsyn, A. P. 1980. Origin and evolution of Hymenoptera. Transactions of the Paleontological Institute of the Academy of Sciences of the USSR 174: 1-192. [in Russian]. Rasnitsyn, A. P. 1983. Ichneumonoidea (Hymenoptera) from the lower Cretaceous of Mongolia. Contributions of the American Entomological Institute 20: 259- 265. Rasnitsyn, A. P. 1988. An outline of evolution of the hymenopterous insects (Order Vespida). Oriental Insects 22: 115-145. Rasnitsyn, A. P. and M.J. Sharkey. 1988. New Eoichneumonidae from early Cretaceous of Siberia and Mongolia (Hymenoptera: Ichneumonoidea). In Gupta, V.K., ed., Advances in Parasitic Hymenoptera Research. E.J. Brill, New York. 546 pp. Shenefelt, R.D. 1969. Braconidae 1, pp. 1-176. In Ferriere, Ch. and J. vand der Vecht, eds. Hymenoptorum Catalogus (nov. ed.). Dr. W. Junk N.V., 's-Gravenhage. Short, J.R.T. 1978. The final larval instars of the Ichneumonidae. Memoirs of the American Entomological Institute 25: 1-508. Stary, P. 1966. Aphid parasites of Czechoslovakia, a review of the Czechoslovak Aphidiidae (Hymenoptera). Academia Publishing House of the Czachosloval Academy of Sciences, Prague. 242 pp. Tobias, V.I. 1968. Voprosy klassifikatsii i filogenii sem. Braconidae (Hymenoptera). Dokladi na Dvadtsatom Ezhegodnom Chtenii Pamyati N.A. Kholodkovskogo, pp. 3-43. [in Russian]. Tobias, V.I. 1989. Application of W. Hennig's method of phylogenetic analysis for the construction of the phylogenetic tree of the family Braconidae (Hymenoptera) Proceedings of the Zoological Institute of the USSR Academy of Sciences, Leningrad 202: 67-83. [in Russian]. Tobias, V.I. and S.A. Belokobylskij. 1984. Aberrant venation in braconids (Hymenoptera, Braconidae) and its significance for the study of the phylogeny of the family. Entomological Review 62: 107-114. Townes, H. 1969. The genera of Ichneumonidae, part 1 . Memoirs of the American Entomological Institute 11: 1-300. Townes, H. 1973. Two ichneumonids (Hymenoptera) from the early Cretaceous. Proceedings of the Entomological Society of Washington 75: 216-219. Wiley, E.O. 1981. Phylogenetics: the theory and practice of phylogenetic systematics. Wiley-Interscience, New York. 439 pp. Zessin, W. 1985. Neue oberliassische Apocrita und die Phylogeny der Hymenoptera (Insecta, Hymenoptera). Deutsche Entomologische Zeitung N.S. 32:129-142. J. HYM. RES. 1(1), 1992 pp. 25-61 An Exploratory Analysis of Cladistic Relationships within the Superfamily Apoidea, with Special Reference to Sphecid Wasps (Hymenoptera)12 Byron A. Alexander Snow Entomological Museum, Snow Hall, University of Kansas, Lawrence, KS 66045, U.S.A. Abstract . — This paper presents the results of several analyses of cladistic relationships among the sphecid wasps and bees, based on adult and larval morphology, with special emphasis on the tribes of sphecid wasps. The analyses examine the effects of: (1) alternative procedures for determining character polarities, (2) using adult characters alone or both adult and larval characters, (3) analyzing all sphecid tribes or only those tribes for which larvae have been described, and (4) equal weighting of all characters vs. successive approximations character weighting. The monophyly of bees is strongly supported, and the following groups of tribes of sphecid wasps are consistently supported as monophyletic: (a) Ampulicini + Dolichurini; (b) (Sceliphrini + (Sphecini + Ammophilini)); (c) (Aphilanthopini + Philanthini + Cercerini + Pseudoscoliini); (d) (Nyssonini + Gorytini + Stizini + Bembicini). Numerous equally parsimonious resolutions of cladistic relationships among these groups and other sphecid tribes are found. In 1 976, R. M. Bohart and A. S. Menke published a monumental worldwide revision of the genera of sphecid wasps. This encyclopedic compilation of information on the taxonomy, geographic distri- bution, and external morphology and behavior of adults represents a milestone in our knowledge of these wasps. Another noteworthy feature of this work is its extensive discussions of phylogenetic relationships among sphecid wasps, although its numerous phylogenetic diagrams are not based upon explicitly stated analytical methods. How- ever, Bohart and Menke (1976: Tables 2, 5, 1 1 , 1 3, 1 5, 16, 19, and p. 224) present numerous lists of "gen- eralized" and "specialized" states of characters considered to be "of phylogenetic significance" in various groups (usually subfamilies). The implicit message seems to be that the branching diagrams are based upon the characters in these tables. Re- gardless of how the phylogenetic diagrams may have been derived, the character analyses sum- marized in the tables do provide the kind of infor- mation necessary for a cladistic analysis. Thus, it should in principle be possible to determine how well these characters support the phylogenetic hypotheses presented by Bohart and Menke, and whether there are other phylogenetic hypotheses that would explain the data equally well or better. 'Contribution No. 3033, University of Kansas ; Throughout this paper, the informal designation "sphecid wasps" will be used to refer to all taxa assigned to the Family Sphecidae as defined by Bohart and Menke (1976). A rigorous cladistic analysis requires two types of information in addition to that presented in Bohart and Menke's tables of character states. One is a clear statement of how the characters have been polarized, and the other is a matrix showing the state of each character for each taxon. Bohart and Menke do not present any data matrix in their book, and it is not possible to construct a complete matrix from their descriptions of taxa or discus- sions of characters. In one of their introductory chapters (p. 29), they do briefly explain how they distinguished between "primitive" and "advanced" states of characters. After discussing the pitfalls of assuming that "simple" characters are primitive and "complex" ones derived, they conclude that "a study of features common in the more primitive hymenopterous families and preserved in some of the Sphecidae is the most productive way of making value judgments on evolutionary paths". This is conceptually close to a method now generally known as outgroup analysis, although more recent formulations of this method (e.g. Watrous and Wheeler 1981, Maddison et al. 1984) are consider- ably more rigorous and explicit. Bohart and Menke also do not identify which hymenopteran families they consider primitive (relative to sphecid wasps). The first explicit cladistic analysis of aculeate Hy- menoptera (Brothers 1975; not cited in Bohart and Menke 1976) presented a hypothesis of the phylo- genetic position of sphecid wasps and bees that was quite different from conventional opinion at the time (e.g. Evans and West Eberhard 1970). 26 Journal of Hymenoptera Research Thus, it is not at all certain that the families re- garded as primitive by Bohart and Menke would be those selected now in the light of new hypoth- eses of phylogenetic relationships among aculeate families that have resulted from explicit cladistic analyses (Brothers 1975, Konigsmann 1978, Car- penter 1990). Another important and influential source of information and ideas about sphecid phylogeny has been presented by H.E. Evans and colleagues, in a series of papers describing sphecid larvae and analysing larval characters from a phylogenetic perspective (Evans 1 957b, 1 958, 1 959, 1 964a, 1 964b, 1966, Evans and Lin 1956a, 1956b, Evans and Matthews 1968). Evans has found larval characters to be most phylogenetically informative for groups that he treats as subfamilies (see especially Evans 1959, 1964). The number of characters employed in his analyses is considerably less than the number of adult characters presented in Bohart and Menke's tables, but a few noteworthy larval characters seem to provide evidence of general patterns of higher- level relationships. The way in which Evans pre- sents and analyzes data on larval characters is very similar to the approach adopted by Bohart and Menke, and the same general remarks on the limitations of this approach apply to both data sets. The potential importance of larval characters for elucidating higher level phylogenetic relation- ships among sphecid wasps was recently re-em- phasized in a cladistic analysis of the relationships between sphecid wasps and bees published by Lomholdt (1982). He partitions the paraphyletic Sphecidae of Bohart and Menke into two groups that he hypothesizes to be monophyletic. His one synapomorphy for the larger of these groups, which he calls Larridae, is a unique form of the openings of the larval salivary glands. This larval character was also stressed by Evans in his papers, and earlier by Michener (1952). Many other authors have also been interested in phylogenetic relationships among sphecid wasps, and the preceding discussion is not intended to be an exhaustive historical review of ideas about sphecid relationships. However, the works men- tioned above are especially noteworthy because of their comprehensive scope, their thoroughness, and the extent to which they have influenced other workers. Evans and co-workers have published several stimulating and frequently-cited papers discussing general evolutionary patterns among sphecid wasps (e.g. Evans 1957a, 1962, 1966a, 1966b, 1966c, Evans and West Eberhard 1970). In recent years, using phylogenetic patterns deduced from cladistic analyses to inform and evaluate theories about evolutionary processes has been more and more widely advocated as a fruitful research pro- gram (Eldredge and Cracraft 1980, Brooks and McLennan 1991, Harvey and Pagel 1991). The growing popularity of this approach makes it even more important to critically assess the strength of evidence supporting published phylogenetic hy- potheses. The present paper is a quantitative cla- distic analysis of the characters identified in the above-mentioned works of Evans (especially Evans 1959 and 1964a) and of Bohart and Menke (1976). I did this study as background work for a re- search project with a narrower focus: a cladistic analysis of the genera in one subfamily, the Philanthinae. Thus, my major objective was to determine whether or not the Philanthinae as de- fined by Bohart and Menke is monophyletic and to establish its phylogenetic placement within the Apoidea (sensu Michener 1986 and Gauld and Bolton 1 988 — i.e., sphecid wasps and bees). Unre- solved relationships among taxa not closely re- lated to the Philanthinae did not prevent me from continuing with my study, so I did not attempt to resolve them. A preliminary report of my analysis was published in a newsletter for aculeate re- searchers (Alexander 1990). I have received several inquiries about that report, and have also given more careful attention to problems involved with outgroup analysis, which have resulted in modified hypotheses of relationships within the Apoidea. The present paper is intended as a more complete presentation of what my exploratory analyses have revealed. Its major conclusion is that much more work remains to be done, but I hope it will also provide a better focus for that future work. METHODS AND MATERIALS As explained above, the starting point for this study was a series of tables of polarized characters taken from the works of Bohart and Menke (1976) and Evans (1959). The sphecid wasps belong to a monophyletic group (Apoidea) that also includes the bees (Apiformes). Characters to establish the monophyly of the Apoidea and Apiformes (bees) are based primarily upon Brothers (1975), supple- mented by discussions in Bohart and Menke (1976) and Michener (1974). I have not examined larval specimens myself, so Volume 1, Number 1, 1992 27 all my assignments of larval character states to taxa are based upon the literature. In addition to the numerous papers of Evans and co-workers cited earlier, Grandi's (1961) excellent illustrations of aculeate larvae are extremely useful. For bee lar- vae, I have relied primarily upon the descriptions by McGinley (1987). Evans' polarity assessments for larval characters are used, since information on larval morphology in the outgroup is unfortunately still too fragmentary for meaningful application of more rigorous analytical procedures. For adult characters, I have examined specimens myself in order to determine the state of each character for each taxon, because such determina- tions cannot always be made from the literature. I have examined representatives of all the sphecid tribes recognized by Bohart and Menke (1976) and all genera for which both adults and larvae are known, as well as a few representatives of each of the major lineages of bees (traditionally assigned the rank of family). Appendix 1 lists the taxa whose adults I have examined. In 1984, Day proposed that the puzzling genus Heterogyna, which was originally placed in its own monotypic family (Nagy 1969), is an aberrant sphecid wasp. It is not included in most of the analyses presented here, which deal with the taxa treated by Bohart, Menke, and Evans. However, I have recently been able to examine male specimens of four of the five known species of Heterogyna, and I accept Day's argument that the males of this genus exhibit the character states that Brothers identified as salient synapomorphies for sphecid wasps and bees, whereas the morphology of females is autapomorphic. I have done one preliminary analysis to determine the phylogenetic position of Heterogyna within Apoidea. The final data matrix (Table 1 ) consists of ninety characters, of which ten are features of larval mor- phology, seventy-nine are features of adult mor- phology, and one is a feature of adult female be- havior (character 72 in Table 2, which lists the characters and character states used in all the analyses). I have selected outgroup taxa from lineages within the Aculeata, as discussed below. Exemplars from the Ichneumonoidea represent an outgroup for the Aculeata, following the unpublished analy- ses of Mason (1983, cited by Carpenter [1986] and Gauld and Bolton [1988]) which hypothesize that the Aculeata and Ichneumonoidea are sister taxa. In each of the analyses presented below, a single "hypothetical ancestor" is used as the outgroup for rooting the trees. Different hypothetical ancestors are used in different analyses. This is done to compare the results of analyses based entirely upon Bohart and Menke's judgments about the polarities of adult characters with the results of analyses based upon polarities that are hypothesized ac- cording to the procedure outlined by Maddison et al. (1984). The latter procedure determines the most parsimonious distribution of each character on a tree comprised of the ingroup and several outgroup taxa. For each character, this optimized character state distribution is used to hypothesize the state that was present in the ancestor of the ingroup. The tree that forms the basis for this procedure is assumed to be an independent and well-supported hypothesis of phylogenetic rela- tionships among the outgroup taxa. In this type of analysis, the character being "fitted" to the tree is not used to derive the tree. For my hypothesis, I have used the tree of aculeate relationships in Fig. 2 of Carpenter's (1990) reanalysis of the data in Brothers ( 1 975). In my 1 990 report in the newsletter Sphecos, I hypothesized the polarity of each character in my matrix as if the tree derived by Brothers and Carpenter were based upon characters completely independent of those I used in my analysis of relationships within the Apoidea. However, a closer examination of Brothers' data set shows that 23 of the 92 characters that he used in his study are also included in my matrix. Because his hypothesis of aculeate rela- tionships is based on his assessment of the polarity of these characters, it would be logically inconsis- tent to use his phylogenetic hypothesis to postulate different polarities for these characters. Conflict about the state to be assigned to a given character at a given node — in this case, the node of interest is the common ancestor of the Apoidea — is pos- sible because the most parsimonious distribution of a single character on a predetermined tree will not necessarily correspond to the optimized dis- tribution of that character when it is used in con- junction with a large number of other characters in order to determine the most parsimonious tree for the entire set of characters. Consequently, for the characters in my matrix that Brothers also used in his study, the states that he hypothesized to be the groundplan state for the Apoidea (which he called the Sphecoidea in his paper) are assigned to the hypothetical ancestor in my matrix. For most characters, the polarities hypothesized 28 Journal of Hymenoptera Research Table 1. Data matrix used in the cladistic analyses. Characters and character states are defined in Table 2. "Outgroup 1" shows the codings used in the preliminary study published in Sphecos (Alexander, 1990), "Outgroup 2" is based on the polarities hypothesized by Bohart and Menke(1976), and "Outgroup 3" is based on the polarities determined by the character state optimization procedure of Maddison et ah (1984). For each taxon entry, the first number is character 0, the last is character 89. A "-" indicates that the character varies within the taxon (for the outgroup, these are characters for which polarity decisions are indecisive), and a "?" indicates that the state is unknown for the taxon (this is primarily used for larval characters, since larvae are undescribed for several taxa). (B and M = Bohart and Menke; optim. = optimized). Outgroup 1 (Sphecos) Outgroup 2 (B and M ) Outgroup 3 (optim.) Ampulicini Dolichurini Sceliphrini Sphecini Ammophilini Astatini Pemphredonini Psenini Mellinini Palarini Miscophini Larrini Trypoxylini Crabronini Oxybelini Alyssonini Nyssonini Gorytini Stizini Bembicini Aphilanthopini Philanthini Cercerini Colletidae Andrenidae Halictidae Melittidae Long-tongued Bees Laphyragogini Xenosphecini Dinetini Heliocausini ntomosericini Eremiaspheciini Odontosphecini Pseudoscoliini Scapheutini Bothynostethini Heterogyna Outgroup 1 (Sphecos) Outgroup 2 (B and M ) Outgroup 3 (optim.) Ampulicini Dolichurini Sceliphrini Sphecini Ammophilini Astatini Pemphredonini Psenini Mellinini Palarini Miscophini Larrini Trypoxylini Crabronini Oxybelini Alyssonini Nyssonini Gorytini Stizini Bembicini 0 1 0000000000-000000 0000000-000010000 00000000000000000 00000100021000000 00000000010000000 00000100010000000 00011110010001-00 00011110010011-00 00000000000000000 00-001-00---00000 00100000010201000 00000000000000001 10010001100-00000 0000000-00000000- 10100001000000001 01-0000-0-0-0--01 00100-0-00-0-0001 00101000000000001 000000000000-0-00 00000000010300000 00-000000-00 0 00100000010001102 10- 120200-0000-02 00000100010001110 01010100010001110 00010100010101110 000100000100-1100 00011100010001100 0-011100010001100 00011100010001100 000131-0010001100 00001000040001100 001100010-001-100 00100001000000000 10100000000000001 00110000010000000 0001010000-000000 10210100000001001 00010100010000110 0010010-000-00001 00--010-0-0000001 00000000000000000 0000000-10-31 0000000000--- 0000000010-31 0100000111120 0002000111021 011-000000-11 1110000000111 -11-000000111 1110000000031 1- 1000010-0-1 11-000010100- 1110000000001 1110000100110 -110000-0000- 1110000000000 111000000--0- 111-000- 0--00 1111011001230 -110000111001 1111100011230 11101000- 111 1 11101-0010111 1110120010111 1110000000- 11 1110000000011 1110000010- 10 1111000000110 1111000010110 11110000-0-10 1111000010110 111100001- 110 1110000000011 2100000010012 1110000000011 1110000001232 1100000100121 -000000000011 1110000010011 1110000010010 1110000- 0-- 10 1110000100010 1110000010002 3 0-0-0 0-000 01000 20010 21011 00001 00011 00001 00110 00110 -01-0 10010 00110 10110 -0110 10110 -01-0 10110 10010 101 10 10010 10110 10-10 2000-0000000 2000001000-0 200010000000 001010010002 000000000000 000001000011 000011-00011 000111100011 000100100000 -0010000100- 1001-0-01001 0001-0010202 100110101000 -001-0-01000 -001-01- 1000 -0010000100- -00110-0100- 110110101000 -00110101200 101100000000 1001---00000 10-11- 110000 10- 11-1- 1000 -0001000 00101000 0-01000 02011101 22011100 00101100 0010110- 00101101 10000000 ---0-0-1 04100001 10000001 -3000011 -0000001 -0000001 -0001001 -0000001 10000001 10000001 1-000001 10000001 1-00-001 10001021 00000 00000 00000 00111 00100 00110 0- - 10 00110 00010 00001 00000 00000 02010 010-- 01010 010-- 01011 01011 01000 01000 00000 10010 -00-0 Aphilanthopini Philanthini Cercerini Colletidae Andrenidae Halictidae Melittidae Long-tongued Bees Laphyragogini Xenosphecini Dinetini Heliocausini Entomosericini Eremiaspheciini Odontosphecini Pseudoscoliini Scapheutini Bothynostethini Heterogyna 00010100 00010100 000-0100 01010100 01- 10100 01- 10100 01110100 01110100 01010000 01110100 10110100 10110101 10110100 10110100 00110100 00110100 10110100 10110100 01000000 10010100 10010100 11010110 0100- 100 01000100 01000100 01001100 01000100 11010100 11010000 10010000 10011000 10010110 11010100 11010110 10010110 10010110 110-0110 11000000 01000000 00000102 01000030 00000100 00000000 0-000000 00000000 000-0-00 00000000 00000000 00000000 01000000 01200000 00000000 00000000 0-000000 01100000 00000000 00000100 100010 100000 101010 10-00- 1000-- 1010-- 100000 10-0-- 100030 100110 000011 100000 010000 0000-0 100010 100000 101010 103000 100031 6 7 8 Outgroup 1 (Sphecos) 010000-210100000-0100000000000 Outgroup 2 (B and M) 000-002 00000000000000000000000 Outgroup 3 (optim.) 010000200000000000000000000000 Ampulicini 120000021010011112100000000002 Dolichurini 010000021010011112100000010002 Sceliphrini 010010210010011112100000000000 Sphecini 010010210010011112100000000000 Ammophilini 010010210010011112100000000000 Astatini 0000002110100111021010101-0010 Pemphredonini 02-0001210100111-21--0U--0110 Psenini 010000-21010011112111011100110 Mellinini 010000021010011112101111030010 Palarini 1100001210100111121011?1010110 Miscophini 00-000-2101001111210111-020110 Larrini - 1 00002- - 01001 1 1 121 01 1 -- 0201 1 0 Trypoxylini 01000002-010011112101111020110 Crabronini 021000021010011112101111020110 Oxybelini 02100102-010011112101111020110 Alyssonini 010000021010011112101011111010 Nyssonini 010100021010011112101001111012 Gorytini --0--0-2101 00 11112101 00 1111011 Stizini 1101-0121010011112101001111010 Bembicini --012002 1010011112101 00011101- Aphilanthopini 0100001210100111121110111- 1110 Philanthini 010000121010011112111011111110 Cercerini 010000-21010011112111011 111110 Colletidae 0-000020112111110210-0--010122 Andrenidae 010000201121 11 110210101 1-10122 Halictidae 01000020112111110210101-01-1-2 Melittidae 010000121121111102101010-101-2 Long-tongued Bees 01 0- 001 - 1 1 2 1 1 1 1 1 021 - 00- - - 1 0- 02 Laphyragogini 00000022001 0? 1 1 1 1 21 ?????????? 0 Xenosphecini 0100001210100111121??????????0 Dinetini 21 010012101001 1 1 121 ????????? ?0 Heliocausini 0100001210100111121??????????3 Entomosericini 010100121010?111121??????????1 Eremiaspheciini 010000121010?111121??????????0 Odontosphecini 0 1 000022 1 0 1 0? 1 1 11 2 1 ?????????? 1 Pseudoscoliini 0100001210100111121??????????0 Scapheutini 110-00121010?111121??????????0 Bothynostethini 010-000210100111121??????????0 Heterogyna 21100002 10100111121???????7??0 Volume 1, Number 1, 1992 29 Table 2. Characters and character states used in the parsimony analyses. Characters marked with an asterisk were treated as nonadditive (= unordered). Character Character States 0. Ocelli 0. Hemispherical, with transparent lens 1. Flattened, oval or linear, or reduced to a transverse scar 1. Inner margin of compound eyes 0. More or less parallel 1 . Notched or emarginate 2.* Facets of compound eyes 0. More or less uniform in size 1. Some facets greatly enlarged ventrally or anteromedially 2. Facets enlarged dorsally, very small ventrally 3. Stipes (on maxilla) 0. Short and broad 1. Long and narrow 4. Galea-glossa complex 0. Short, broad, flap-like 1. Moderately elongated, not flap-like 2. Greatly elongated, subtubular 3. Greatly elongated, flattened, enclosed ventrally by labial palpi, which have the basal two segments greatly elongated and flattened, the apical two segments much shorter, subcylindrical 5. Mandibular socket 0. Open 1. Closed 6. Labrum 0. Short, wider than long, usually hidden by clypeus 1. About as long as wide 2. Longer than wide, extending well beyond clypeus 7. Externoventral tooth or notch on mandible 0. Absent 1. Present 8. Clypeus subdivided by distinct longitudinal lines 0. No 1. Yes 9*. Shape of clypeus 0. Narrowly transverse 1. Not transverse, but with a dorsally produced median portion 2. Sharply rooflike (Ampulicini) 3. Swollen, to accomodate proboscis when folded (Bembicini) 4. Not transverse, but with a ventrally produced median portion 10. Gular area 0. Narrow, so that hypostomal carina is close to occipital carina 1. Broad, hypostomal carina widely separated from occipital carina 11*. Frontal carina 0. Absent 1 . Present, evenly convex in profile, linear in frontal view 2. Present, sharply angulate in profile, shaped like an inverted T in frontal view 3. Present, a very broad ridge rather than a narrow carina (Nyssonini) 12. Frontal sulcus 0. Absent 1. Present 13. Antennal sockets 0. Contacting clypeus, or separated from it by less than half the diameter of a socket 1. Separated from clypeus by more than half the diameter of a socket 14. Subantennal sclerite delimited by subantennal sutures (= supraclypeal area of Michener, 1944) 0. absent 1 . present 15. Clypeal brush (in males only) 0. absent 1 . present 16*. Propleuron 0. Not specially modified 1. Posterolateral margin lamellate, posterolateral angle declivous and set off from rest of propleuron by inner ridge or hump 2. Anterior face flattened, somewhat compressed in lateral view, ventral margin and ventrolateral corner lamellate 17*. Pronotal collar 0. Long, not collar-like 1. Narrowly transverse, collar-like 2. Evenly sloping from neck of pronotum up to scutum, so that there is no discernible collar (Astatini) 18. Pronotal lobe 0. Contacting or nearly contacting tegula, so that scutum does not contact mesopleuron 1. Separated from tegula by anterolateral process or carina from scutum, so that scutum directly contacts mesopleuron 19. Notauli 0. Present, long 1 . Absent or very short (not reaching an imaginary line tangent to anterior margins of tegulae) 20*. Admedian lines of scutum 0. Separate, distinct 1. Fused into a single median line 2. Absent 21 . Oblique scutal carina 0. Absent 1. Present 22*. Scutellum 0. Without lateral flange 1. With lateral flange overlapping metanotum 2. A horizontal, strap-like band tightly appressed to metanotum, posterior margin lamellate 23. Metanotal squamae 0. Absent 1. Present 24. Scutellum with a pitted transverse basal sulcus 0. No 1. Yes 25. Episternal sulcus 0. Present, long (extending ventrad of scrobal sulcus) 1. Short (not extending ventrad of scrobal sulcus) or absent 30 Journal of Hymenoptera Research 26. Omaulus 0. Absent 1. Present 27*. Postspiracular carina 0. A narrow, sharp ridge forming the vertical anterior wall of the subalar fossa 1. A broad, rounded ridge forming the vertical anterior wall of the subalar fossa 2. Absent, because subalar fossa is absent or separated into anterior and posterior pits 28*. Subalar line 0. Absent or incomplete, but subalar area not reduced 1. Present, but not greatly expanded into a carinate ridge or flange 2. Present as a very prominent carina or flange 3. Absent, subalar area greatly reduced or absent 29*. Separation of middle coxae 0. Metasternum quadrate or rectangular, on more or less the same plane as mesosternum, so that midcoxae are widely separated 1. Similar to 0, but metasternum distinctly narrowed anteriorly, so that midcoxae are close together 2. Metasternum on a different plane from that of mesosternum 30. Posterior margin of metasternum 0. Broadly rounded, truncate, or weakly emarginate 1. Bilobed, lobes subparallel and closely approximated 2. Bilobed, lobes diverging apically 31. Precoxal lobes 0. Present, delineated by distinct transverse groove from mesosternal apophyseal pit 1. Absent 32. Dorsolateral carina on middle coxa 0. Absent 1. Present 33. Lower metapleural area 0. Present 1. Absent 34. Propodeal sternite 0. Absent 1. Present 35*. Propodeal enclosure 0. Present, U-shaped 1. Present, V-shaped 2. Absent 36. Propodeal mucro 0. Absent 1. Present 37. Lateral spines or teeth on propodeum 0. Absent 1. Present 38. Tarsal claws 0. Bifid or with subapical teeth or lobe 1. Simple 39. Plantulae 0. Present 1. Absent 40. Apicoventral setae on hindtarsomere V 0. Setiform 1. Bladelike 41. Foretarsal rake (in females) 0. Absent 1. Present 42. Tarsomeres 0. IV similar to III, V inserted toward apex of IV 1. IV short, V inserted dorsally at base of IV 43. Number of midtibial spurs 0. Two 1. One 44*. Apex of hind femur 0. Unmodified 1 . Broadened, truncate 2. With an apical spatulate process 45. Insertion of metasoma 0. Between hind coxae 1. After and above hind coxae 46*. Metasomal petiole 0. Absent 1. Formed of first metasomal sternum only 2. Formed of first metasomal sternum and first metasomal tergum 47*. Base of first metasomal sternum 0. Simple, without any carinae 1. With longitudinal median ridge or paired ridges 2. With distinct transverse ridge 48*. Shape of second metasomal sternum 0. Evenly convex, not swollen at base 1. Swollen at base, but without a transverse sulcus 2. Swollen at base, with a transverse sulcus at base of swollen area 3. Palarini — varies between sexes and species, but usually a very prominent subapical transverse ridge (especially in males) 4. Similar to state 2, but with a pair of basilateral nodes bearing tufts of very short, fine setae 49. Lateral line or carina on tergum 1 0. Present 1. Absent 50. Number of visible metasomal terga in males 0. Seven 1. Fewer than seven 51 . Pygidial plate (in females) 0. Present 1. Absent 52*. Sixth metasomal sternum (females) 0. Similar to other segments, except for troughlike vertical side walls 1. Elongate, forming an exposed tapering tube through which sting is exserted 2. Apically bifid or emarginate 53*. Apex of female metasoma 0. More or less conical 1. Strongly compressed laterally 2. Strongly compressed dorsoventrally 54. Cerci (males) 0. Present 1. Absent 55. Laterobasal spiracular lobes on male tergum 7 0. Absent 1. Present 56*. Volsella 0. With differentiated digitus and cuspis 1. Digitus and cuspis fused, not differentiated 2. Absent 3. A large, rolled, C-shaped plate (Bothynostethini) 57. Penis valves (= "aedeagal head") Volume 1, Number 1, 1992 31 0. Without teeth on apicoventral edge 1 . With numerous short teeth on apicoventral edge 58*. Apex of marginal cell 0. Acuminate, ending on costal margin of wing 1 . Evenly truncate or broadly rounded 2. Open (in some outgroup taxa) 3. Obliquely truncate, not ending on costal margin of wing 59. Number of submarginal cells 0. Three 1 . Two or fewer 60*. Forewing vein 3rs-m ("outer veinlet of 3rd submarginal cell" in Bohart & Menke, 1976) 0. Ending near middle of marginal cell (= Rl cell) 1. Ending near apex of marginal cell 2. Absent 61*. Forewing vein 2-Rs ("outer veinlet of 1st submarginal cell" in Bohart & Menke, 1976) 0. Angled, and with a remnant of vein lr-rs (1st radial cross-vein) 1. Straight or weakly curved, not appendiculate, no remnant of lr-rs 2. Absent 62. Number of discoidal cells in forewing 0. Three 1 . Two or fewer 63. Divergence of forewing vein M 0. At or after vein cu-a 1. Before vein cu-a 64. Prestigmal length of 1st submarginal cell 0. Less than twice height of cell 1. Between two and three times height of cell 2. More than three times height of cell 65. Submarginal and discoidal cells 0. Separated by vein Rs+M 1. Fused, due to loss of vein Rs+M 66. Jugal lobe 0. Small or absent 1. About 1/2 as long as vannal lobe 2. More than 3/4 as long as vannal lobe 67. Hind wing vein 2A 0. Present as a tubular vein 1 . Present as a nebulous or spectral vein 2. Absent 68. Hind wing vein 3A 0. Present 1. Absent 69. Body vestiture 0. Without plumose setae 1 . With at least some plumose setae 70. Female metasomal tergum 7 0. Somewhat exposed, evenly sclerotized throughout 1. Retracted and entirely hidden from external view, sclerotization reduced to a short strip across anterior margin 2. Sclerotization entirely reduced mesally so that the lateral spiracular plates (hemitergites) are linked by membrane only 71. Female hind basitarsus 0. Subcylindrical, about as wide as tarsomeres 11 - V 1. Flattened, wider than tarsomeres II - V 72. Larval provisions 0. Arthropods (usually paralyzed) 1. Pollen and nectar or plant oils 73. Posterolateral angle of pronotum 0. Evenly rounded or subacute, reaching tegula 1. Reduced dorsally above and slightly anterior to spiracular operculum; operculum forms a highly differentiated pronotal lobe 74. Ventral angle of pronotum 0. Rounded, not much exceeding level of base of fore coxa 1. Greatly produced, almost contacting its counterpart ventrally 75. Metapostnotum 0. Forming a transverse groove at anterior margin of propodeum 1. Greatly enlarged and posteriorly produced mesally, forming a "propodeal enclosure" or "propodeal triangle" 76. Hindtibial strigilus 0. Absent 1. Present 77* . Hind margin of pronotum 0. Pronotum long, hind margin nearly straight, only very slightly anteriorly arcuate 1. Pronotum shortened, hind margin strongly concave in a fairly regular and somewhat arcuate parabolic curve ("V-shaped") 2. Pronotum shortened, hind margin shifted anteriorly over almost its entire width ("broadly U-shaped") 78. Prosternum 0. Forming an approximately uniform plane, not sunken 1. Sunken over most of its surface, only a short anterior section visible ventrally 79. Larval integument 0. Smooth 1. With abundant setae or dense spinules 80. Larval body shape 0. With more or less even contours 1. With conspicuous projections laterally, dorsally, or caudally 81 . Position of larval anus 0. Terminal, directed caudad 1. Ventral, preapical, directed ventrad 82. Opening between atrium and sub-atrium of larval spiracles 0. Armed with a circlet of spines 1. Simple, unarmed 83. Parietal bands (on head of larva) 0. Present 1. Absent, or very faintly indicated 84. Larval antennal papillae 0. Absent 1. Present 85*. Larval mandibles 0. Simple, with 4 or 5 apical teeth 1 . With fewer than 4 or 5 teeth 2. With an apical concavity 3. As in Mellinini (autapomorphy) 86. Larval maxillae 0. Directed mesad apically, closely associated with labium and hypopharynx 1. Projecting apically as large, free lobes 87. Larval galea 32 Journal of Hymenoptera Research 0. Large 2. Small 88*. Larval spinneret 0. A transverse slit 1 . With paired openings, each at the end of a projection 2. Absent 89. Male metasomal sternum 7 0. Well developed, not much smaller than sternum 6, usually clearly visible externally and exposed 1. Reduced and much smaller than sternum 6, but partly exposed 2. Greatly reduced, much smaller than sternum 6 and completely hidden by it 3. Absent by Bohart and Menke are supported by the more rigorous analytical procedure described above. Table 3 lists the seven characters for which the optimization procedure results in a different po- larity assessment from that hypothesized by Bohart and Menke. There are an additional twelve charac- ters for which one procedure yields uncertain or equivocal results, whereas the other hypothesizes a single unequivocal groundplan state. Thus, a total of nineteen characters do not receive identical polarity codings with each procedure. A few of the optimized polarity decisions are at odds with rather widely accepted ideas about character evolution in sphecid wasps and bees. Especially noteworthy in this respect are the episternal sulcus (character 25), plantulae (character 39), and foretarsal rake (character 41). Bohart and Menke hypothesize that an episternal sulcus extending ventrad of the scrobal sulcus is the plesiomorphic condition for the Sphecidae, and bee systematists have generally regarded this character state as plesiomorphic for bees. For both groups, the basis of this assessment seems to be that a long episternal sulcus is present in taxa which generally have plesiomorphic states for other characters. Most taxa outside the Apoidea have no sulcus at all in the position of the episternal sulcus, but some Bethylidae (e.g. Epi/ris clarimontis) may have one. My analyses use Bohart and Menke's coding of "episternal sulcus absent or short" (Character 10 in their Table 2, p. 30; Character 25, state 1 in my Table 2) as a single character state. Under this coding, outgroup taxa are scored as having the episternal sulcus absent (or variable in Bethylidae), and the character state optimization procedure infers that the ancestor of the Apoidea had the episternal sulcus "absent or short". If Table 3. Characters for which Bohart and Menke (1976) postulated different groundplan states from those derived by an optimized fit to a cladogram of aculeate taxa based on the studies of Brothers (1975) and Carpenter (1990), using the optimization procedure presented by Maddison et al. (1984). Characters and character states are defined in Table 2, and are merely given brief labels here. The column labelled "B & M" shows the groundplan state postulated by Bohart and Menke. This column corresponds to Outgroup 2 in Table 1. A "?" indicates that Bohart and Menke expressed doubt as to the plesiomorphic condition for the character, or did not indicate what they considered the plesiomorphic state to be. The column labelled "Optimized" shows the state assigned to the ingroup node (i.e. the state present in the ancestor of the Apoidea) as determined by the optimization procedure mentioned above. This column corresponds to Outgroup 3 in Table 1. Characters in this column denoted by a (B) are ones that Brothers used in his study, so that groundplan states for these characters are based upon his polarity assessments rather than the tree-fitting procedure of Maddison et al. (1984). Characters denoted by a "-" in this column and the "Sphecos" column are those for which polarity decisions were indecisive. The column labelled "Sphecos", equivalent to Outgroup 1 in Table 2, shows the groundplan states used in a preliminary analysis that I published in the newsletter Sphecos (Alexander, 1990). In that analysis, I did not distinguish between characters in my data matrix that had and had not been used by Brothers in his study. Instead, the groundplan state of each character was determined by optimizing its fit to Brothers' cladogram, regardless of whether or not the character had been used to derive the cladogram. Character Spr lecos B&M Optimized 7. Mandibular notch 0 ? 0 10. Gular area - 0 0 12. Frontal sulcus 0 1 0 24. Scutellar sulcus - 0 0 25. Episternal sulcus 1 0 1 29. Separation of midcoxae 0 ? 1 (B) 31. Precoxal lobes - ? 1 33. Lower metapleural area - 0 0(B) 39. Plantulae - 0 1 41. Foretarsal rake 0 1 0 45. Insertion of metasoma 0 ? 0 47. Base of sternum 1 - 0 - 49. Lateral line on tergum 1 - 1 - 61. Forewing vein 2-Rs 1 0 1 63. Divergence of vein M 0 ? 0 66. Jugal lobe - 2 2(B) 67. Hind wing vein 2A 2 0 0(B) 68. Hind wing vein 3A 1 0 0(B) 76. Hindtibial strigilus - 0 0 Volume 1, Number 1, 1992 33 "absent" and "short" were coded as separate char- acter states, the groundplan state for Apoidea would be equivocal, because the ingroup would have two derived states, neither of which occurs in the outgroup. A similar argument explains the hypothesis that the absence of a foretarsal rake in females is plesiomorphic. In the outgroup taxa that I have examined, only Anthoboscinae and some Pompilidae have a foretarsal rake. In Brothers' original (1975) analysis, Apoidea and Vespoidea are sister taxa, and the first clade to branch off within Vespoidea is (Tiphiidae [with Anthoboscinae as the basal group] + (Sapygidae + Mutillidae)). In Carpenter's (1990) reanalysis of Brothers' data, Sierolomorphidae is the basal clade in Vespoidea. Females of Anthoboscinae, and some Sapygidae I have examined for this character (e.g. Fedtschenkiaanthracina), have a foretarsal rake. Thus, if Brothers' original hypothesis of aculeate relationships is correct, the ancestral state of the foretarsal rake in Apoidea would be equivocal. Carpenter's cladogram supports the conclusion that the ancestor of Apoidea had no foretarsal rake. In the outgroup, I find plantulae to be present in Pompilidae, Anthoboscinae, and some Rhopalosomatidae. Such a distribution results in the hypothesis that plantulae are primitively absent in Apoidea if Carpenter's cladogram is used. If Brothers' cladogram is used, the groundplan state for Apoidea is equivocal. With the basic data matrix of Table 1, I have performed analyses to examine the effects of altering three variables: the taxa examined, the characters employed, and the groundplan character states for the hypothetical ancestor. The two different groups of taxa considered are ( 1 ) only those for which both adults and larvae have been described, and (2) all sphecid tribes, including those for which only adults are known. Including taxa for which only adults are known in an analysis that uses larval characters results in a data matrix with numerous "empty" cells (denoted by a "?" in Table 1). Although I use a parsimony program (Hennig86) that can analyze a matrix with missing information, the usual result of doing such an analysis is poorer resolution of phylogenetic relationships. The alternative is to completely ignore certain taxa because of insuffi- cient information about them. Neither approach is completely satisfactory. By comparing the results of both approaches, one can at least find out if there are any patterns of phylogenetic relationships sup- ported by both sets of incomplete information. A similar rationale explains why I wish to com- pare the results of analyses that use both adult and larval characters with the results of analyses that use only adult characters. Finally, I examine the results of using a hypothetical ancestor based upon Table 4. Combinations of variables employed in the quantitative cladistic analyses. For hypothetical ancestor codings, the column labelled "Literature" utilized codings hypothesized in the literature, primarily by Bohart and Menke (1976) and Evans (1959), and the column labelled "Optimized" utilized codings based upon the procedures described by Maddison et al. (1984), as explained in the text. For each of the analyses designated by number in the table, there was also a part (a) in which all characters were given equal weight, and a part (b) in which successive approximations character weighting was used. Thus, Analysis 1 b used hypothetical ancestor codings based on the literature, only sphecid tribes whose larvae are known, adult and larval characters, and successive approximations character weighting. Hypothetical Ancestor Codings Taxa Employed Literature Optimized Only sphecids whose larvae are known All Sphecid Tribes Analysis 1: Adult & larval characters Analysis 2: Adult characters only Analysis 3: Adult & larval characters Analysis 4: Adult characters only Analysis 5: Adult & larval characters Analysis 6: Adult characters only Analysis 7: Adult & larval characters Analysis 8: Adult characters only 34 Journal of Hymenoptera Research the polarity decisions of Bohart and Menke with the results of using a hypothetical ancestor based upon polarity decisions derived from character state optimization. This 2x2x2 arrangement of variables requires eight basic analyses. For each of these analyses, I also compare the results obtained when all characters are given equal weight with the results obtained when characters are weighted according to Farris' (1969) successive approxima- tions procedure. Table 4 summarizes the combina- tions of variables used in each analysis. As explained above, the assessments of character polarities made by Bohart and Menke agree with the results of a more formal analytical procedure for all but 19 of the characters included in the data matrix that I used. I therefore also examine the results of an analysis that excludes these 19 char- acters (the characters are listed in Table 3). For this analysis, I include all sphecid tribes and both adult and larval characters (except for the 19 characters just mentioned). The analysis including Heterogyna uses all sphecid tribes, adult and larval characters (the latter coded as unknown for Heterogyna and 10 other tribes), and the character state optimization procedure for outgroup analysis. All analyses discussed below employed J.S. Farris' Hennig86 program, Version 1.5 (Farris 1988), and used the commands m* and bb* to search for the most parsimonious trees. Use of the bb* option was time-consuming, especially when numerous iterations were necessary in the suc- cessive approximations character weighting pro- cedure. (According to Farris [1988], the bb com- mand will not retain more than 100 minimum- length trees that are found in an extended branch- swapping procedure, whereas the bb* command will retain all minimum-length trees.) Compari- son of results obtained with the bb and bb* com- mands for the same data set showed that they resulted in different final weights assigned to some characters and thus different hypotheses of phylo- genetic relationships. In view of this, I considered it preferable to use the more exhaustive branch- swapping procedure, under the assumption that it was taking complete account of all the available information, instead of using an arbitrary cut-off point in searching for multiple minimum-length trees. In these analyses, the tribes of Sphecidae as defined by Bohart and Menke are used as the terminal taxa. This taxonomic level has been se- lected primarily for reasons of analytical tractabil- ity. Bohart and Menke recognize 226 genera and 7,634 species of sphecid wasps, so even an analysis at the level of the genus would require an ex- tremely large and cumbersome matrix. Grimaldi (1 990) reported an attempt to analyze a matrix with 158 taxa in the dipteran family Drosophilidae us- ing the Hennig86 program. He found that "initial runs ... using the complete matrix were never fin- ished, so the matrix was gradually pared down until it was found that 127 taxa was the maximum number that the program could analyze (at least using the m*; bb commands)." The analytical tractability of a data matrix depends not only on the number of taxa, but also on the level of character conflict, with high levels of character conflict re- sulting in poor resolution, or multiple equally parsimonious resolutions. The results to be pre- sented below show high levels of character conflict. The major shortcoming of using tribes (or gen- era) as terminal taxa is that several of them are almost certainly paraphyletic, and treating such taxa as monophyletic adds yet another source of error and confusion in a phylogenetic analysis. Table 5 lists the tribes of sphecid wasps that are most likely to be paraphyletic, because they are defined by character states that Bohart and Menke themselves regard as plesiomorphic at the level of the tribe they define. Because of uncertainty about which tribes are monophyletic, a few of the char- acters in the matrix I used are autapomorphies. Although such characters are not useful for deter- mining phylogenetic relationships among tribes, they do provide evidence that the tribe possessing them is monophyletic. Even with autapomorphies, the consistency indices for these analyses are low enough that anyone who erroneously tries to use this index as a measure of confidence in a phylo- genetic hypothesis should be unlikely to develop a false confidence in these particular hypotheses. RESULTS Each of the analyses results in numerous equally parsimonious trees (range: 9 to 5,272 trees; tree statistics summarized in Table 6). Thus, the first conclusion is that these data provide support for a large number of competing hypotheses about phy- logenetic relationships within the Apoidea. Fig- ures 1-10 summarize the results of each analysis in a manner that facilitates comparison, although it is important to remember that the diagrams being compared are consensus trees, and that the actual Volume 1, Number 1, 1992 35 Table 5. Tribes in Bohart and Menke's (1976) classification that are defined by characters that they considered to be plesiomorphic at the level of the tribe. TRIBE COMMENTS Sceliphrini Apparently paraphyletic with respect to Sphecini + Ammophilini. Bohart and Menke interpreted the presence of plantulae in the Sphecinae as plesiomorphic, but the optimization procedure for establishing character polarity would interpret the presence of plantulae as an autapomorphy for Sceliphrini, although this character exhibits high levels of homoplasy. Astatini Includes all genera of subfamily Astatine except Dinetus. Miscophini Apparently paraphyletic with respect to other tribes of Larrinae. Crabronini Apparently paraphyletic with respect to Oxybelini. Gorytini Apparently paraphyletic with respect to other tribes of Nyssoninae. Stizini Apparently paraphyletic with respect to Bembicini. Aphilanthopini Apparently paraphyletic with respect to other tribes of Philanthinae. Table 6. Summary statistics for the analyses defined in Table 4; C.I. = consistency index, R.I. = retention index. Analysis 9 used all sphecid tribes and both adult and larval characters, but excluded the nineteen characters listed in Table 3. "Heterogyna" refers to the analysis including the enigmatic genus Heterogyna. Length C.I. R.I. No. of Trees Analysis la 274 .44 .65 5272 lb 726 .73 .84 108 Analysis 2a 242 .44 .63 42 2b 633 .75 .83 99 Analysis 3a 346 .37 .60 3994 3b 686 .72 .85 3994 Analysis 4a 314 .37 .58 3994 4b 609 .70 .82 347 Analysis 5a 273 .44 .65 555 5b 722 .73 .83 162 Analysis 6a 244 .44 .62 854 6b 654 .77 .84 90 Analysis 7a 347 .37 .60 156 7b 669 .72 .84 330 Analysis 8a 316 .37 .58 15 8b 597 .70 .82 46 Analysis 9a 248 .41 .64 2009 9b 570 .74 .86 3992 Heterogyn a a 356 .36 .60 351 b 698 .68 .82 9 number of competing hypotheses is far higher than what is shown pictorially. Appendix 2 presents a brief discussion of the ambiguities involved in mapping character state distributions onto consen- sus trees. Despite the large number of competing hy- potheses that merit consideration, a few consistent patterns appear in all the analyses. Table 7 identifies groupings of terminal taxa that are consistently supported as monophyletic groups, and lists the characters that are always interpreted as synapomorphies for these groups. It seems rea- sonable to regard these groups as strongly sup- ported by the available evidence, and it is notewor- thy that most of them are groups that have long been regarded as "natural" and are similar or identical in composition to the subfamilies in Bohart and Menke's classification. Table 8 compares the monophyletic groups consistently supported in this study with the classification proposed by Bohart and Menke. Just as noteworthy as the groupings of sphecid tribes that are consistently supported as mono- phyletic are traditional groupings that receive little or no support as monophyletic taxa. Judging from the results of these analyses, the subfamilies Pemphredoninae and Astatinae of Bohart and Menke's classification do not appear to be mono- phyletic. Each of these subfamilies consists of two tribes (one of the tribes of Astatinae is monotypic). Character states that Bohart and Menke use to unite these tribes into subfamilies appear to be plesiomorphic. The monophyly of each tribe was not investigated in this study. One final general observation is that very few consistent and strongly supported patterns of re- lationships among major monophyletic groups within the Apoidea are found. In Figures 1-10, many of the internal branches are supported by very few characters, and most of these characters exhibit homoplasy. The group of three tribes corresponding to Bohart and Menke's subfamily Sphecinae is consis- tently a basal lineage, and most of the remaining tribes share a substantial number of syn- apomorphies. The Ampulicinae of Bohart and Menke is a problematic group in this respect, how- ever. In most of the analyses in which only adult characters are used, the Ampulicinae is placed in monophyletic groupings that also include several 36 Journal of Hymenoptera Research Table 7. Groupings of terminal taxa that were consistently supported as monophyletic groups, and characters that were consistently hypothesized to be synapomorphies for each group. Character states are numbered as in Table 2. AMPULICINAE (Ampulicini + Dolichurini) 24-1 Pitted transverse basal sulcus on scutellum (also occurs in nine other tribes, may vary within tribes). 28-2 Subalar line a very prominent carina or flange (also in Entomosericini). 30-2 Posterior margin of metasternum distinctly bilobed, lobes diverging apically. 48-2 Metasomal sternum 2 swollen at base, with a transverse sulcus or carina (also in Entomosericini). 50-1 Male with fewer than seven visible metasomal segments. SPHECINAE (Sceliphrini + (Sphecini + Ammophilini)) 5-1 Mandibular socket closed (also in Ampulicini, Pemphredonini, Scapheutini, most Philanthinae and bees, some Crabronini). 34-2 Propodeal sternite present (also in Dolichurini). 40-1 Apicoventral setae on hindtarsomere V bladelike (varies within Gorytini, Stizini, and Bembicini). 45-1 Insertion of metasoma after and above hind coxae (also in Dolichurini, according to Bohart and Menke). 46-1 Metasomal petiole formed of sternum 1 only (also in Psenini, and in some Pemphredonini, Trypoxylini, and Crabronini). 64-1 Prestigmal length of first submarginal cell less than twice height of cell (also in some Gorytini and Stizini). Sphecini + Ammophilini 3-1 Stipes long and narrow (also in Palarini, Bembicini, Entomosericini, Xenosphecini, bees, most Phil- anthinae). 4-1 Galea-glossa complex long and narrow (also in Oxybelini, bees except Colletidae). 6-1 Labrum subquadrate. 13-1 Antennal sockets separated from clypeus by more than half the diameter of the socket (also in Psenini, Stizini, Laphyragogini,Odontosphecini, Xenosphecini, bees, most Philanthinae, some Trypoxylini and Gorytini). APIFORMES (Bees) 20-1 Admedian lines of scutum fused into a single median line 27-1 Postspiracular carina a broad, rounded ridge forming the vertical anterior wall of subalar fossa (interpreted as a reversal in these analyses). 38-0 Tarsal claw bifid or with subapical teeth or lobes (interpreted as a reversal in these analyses). 41-0 Foretarsal rake absent (interpreted as a reversal in these analyses). 69-1 Body vestiture including some plumose hairs. 70-2 Female metasomal tergum 7 divided into hemitergites. 71-1 Female hind tarsus flattened, wider than more distal tarsomeres. 72-1 Larval provisions consist of pollen and nectar or plant oils. 89-2 Male metasomal sternum 7 greatly reduced, much smaller than sternum 6 and completely hidden by it. 88 Larval spinnerets: variable, but never with paired openings, each at the end of a projection, so this character is interpreted as undergoing reversal in these analyses. (By comparison, Lomholdt (1982) interpreted the absence of paired spinnerets in bees as plesiomorphic.) PHILANTHINAE s. str. (Aphilanthopini, Philanthini, Cercerini, Pseudoscoliini) 15-1 Male with a clypeal brush. 32-0 Middle coxae without a dorsolateral carina or crest (interpreted as a reversal in these analyses). 86-1 Larval maxillae projecting apically as free lobes (also in Nyssoninae). APIFORMES + PHILANTHINAE 14-1 Delimited subantennal sclerite NYSSONINAE s.str. (Nyssonini, Gorytini, Stizini, Bembicini) 21-1 Oblique scutal carina (in all analyses except 8b, in which these tribes are a paraphyletic assemblage). 82-0 Opening between atrium and subatrium of larval spiracles armed with a circlet of spines (interpreted as a reversal in these analyses). Stizini + Bembicini 16-2 Propleuron with anterior face flattened, somewhat compressed in lateral view, ventral margin and ventrolateral corner lamellate AMPULICINAE + SPHECINAE (sister taxa only in Analyses 3b, 5b, 6b, and 7b) 9-1 Clypeus not transverse, but with dorsally produced median portion (further modified in Ampulicini) 52-1 Female metasomal sternum 6 elongate, forming an exposed tapering tube through which sting is exserted . 57-1 Penis valves with small teeth on ventral edge. 76-1 Hindtibial strigilus present (also present in most other Apoidea except Apiformes). tribes traditionally assigned to the Nyssoninae. Such a relationship has been suggested before, on the basis that the scutum overlies the tegula (Pate 1 938), although Pate himself expressed reser- vations about this relationship. Most sphecid workers have not accepted the hypothesis of a close relationship between the Ampulicinae and Nyssoninae. It is worth noting that in the analyses hypothesizing that the Ampulicinae are part of the Nyssoninae (usually the sister group of Nyssonini), none of the putative synapomorphies for these taxa are unique to them. The characters consis- tently hypothesized as synapomorphies are pres- ence of an omaulus (character 26-1 in Table 2); loss of a foretarsal rake (41-0, shared by Ampulicinae Volume 1, Number 1, 1992 37 Table 8. A comparison of Bohart and Menke's (1 976) subfamilial classification of sphecid wasps with tribal groupings that were consistently hypothesized as monophyletic in this study. Monotypic subfamilies in Bohart and Menke's classification are not listed here, because in this study they were assumed to be monophyletic by definition. BOHART AND MENKE AMPULICINAE (tribes Ampulicini and Dolichurini) SPHECINAE (tribes Sceliphrini, Sphecini, and Ammophilini) PEMPHREDONINAE (tribes Psenini and Pemphredonini) ASTATINAE (tribes Astatini and Dinetini) LARRINAE (tribes Larrini, Palarini, Miscophini, Trypoxylini, Bothynostethini, and Scapheutini) CRABRONINAE* (tribes Crabronim and Oxybelini) THIS STUDY Same as in Bohart & Menke Same as in Bohart & Menke Monophyletic group only in consensus trees from Analyses 7a and 8a. Not a monophyletic group in any consensus trees. A monophyletic group of only these tribes was not consistently supported in all analyses, but many tribes of Bohart & Menke's Larrinae and Crabroninae frequently formed a monophyletic assemblage. The assemblage sometimes also included Alyssonini, Mellinini, and /or Heliocausini, and Larrini and Palarini were sometimes not included with the other tribes. *Menke (1988) now advocates including Oxybelini and Crabronini with the Larrinae, and no longer recognizes the subfamily Crabroninae. NYSSONINAE (tribes Mellinini, Heliocausini, Nyssonini, Alyssonini, Gorytini, Bembicini, Stizini) PHILANTHINAE (tibes Eremiaspheciini, Philanthini, Aphilanthopini, Odontosphecini, Pseudoscoliini, Cercerini) The tribes Nyssonini, Gorytini, Stizini, and Bembicini consistently formed a monophyletic assemblage, although this assemblage sometimes also included Ampulicini, Dolichurini, Entomosericini, and/ or Psenini. Aphilanthopini, Philanthini, Pseudoscoliini, and Cercerini consistently formed an exclusive monophyletic assemblage. Eremiaspheciini and Odontosphecini were never included in this assemblage. and Nyssonini, the latter group consisting of cleptoparasites); hind wing jugal lobe small or absent (66-0); and male metasomal sternum 7 greatly reduced and hidden by sternum 6 (89-2). In analy- ses that hypothesize a sister group relationship between Ampulicinaeand certain Nyssoninae, the ancestor of Ampulicinae is required to undergo numerous character state reversals, including loss of the oblique scutal carina (21-1). This character is unique to the tribes Bembicini, Gorytini, Nyssonini, and Stizini, which means that in this study it is a major character supporting the mono- phyly of these four tribes as a group ( "Nyssoninae" in a narrow sense). The carina is not present in all members of Gorytini. Because this tribe is paraphyletic, the phylogenetic significance of the absence of the carina in some gorytine genera is unclear. Many of the analyses in which both adult and larval characters are used hypothesize a sister group relationship between the Ampulicinae and the Sphecinae. Although Evans (1959, 1964) empha- sizes the similarities in the larvae of these two groups, these similarities are features that he con- siders plesiomorphic, and in my analyses all the characters suggesting a sister group relationship between the two groups are features of adult morphology. The most frequently hypothesized synapomorphies are the dorsally produced clypeus (9-1), female metasomal sternum 6 forming a tube through which the sting is exserted (52-1), toothed penis valves (57-1), and presence of a hindtibial strigilus (76-1, also present in most other sphecids, but independently derived in Ampulicinae + Sphecinae if they are sister taxa). Apart from the basal position of the Sphecinae 38 Journal of Hymenoptera Research (and probably the Ampulicinae), the other consis- tent result of these analyses is a close relationship between the bees and the Philanthinae (i.e tribes Aphilanthopini, Cercerini, Philanthini, and Pseudosoliini — the tribes Eremiaspheciini and Odontosphecini, which Bohart and Menke placed in the Philanthinae, do not form a monophyletic grouping with these other four tribes in my analyses). In analyses that include all sphecid tribes, one or more of the following tribes are occasionally included in a monophyletic group that also contains the bees and Philanthinae: Psenini, Pemphredonini, Laphyragogini, and Xenosphecini (the last two tribes each contain one genus). Only one character is consistently hypoth- esized as a synapomorphy of bees and philanthines in all the analyses. This is a feature referred to by Bohart and Menke as a "delimited subantennal sclerite", which is equivalent to what bee special- ists (following the terminology of Michener 1944) call the "supraclypeal area", and is not the same as Michener's "subantennal area". Perhaps it would be less confusing to think of this character in terms of the presence or absence of a subantennal suture extending from the dorso-lateral angle of the clypeus toward the antennal socket. Other char- acters hypothesized as synapomorphies of bees and philanthines in some, but not all, of the analyses are: elongated stipes (character 3-1), a closed mandibular socket (5-1), antennal sockets not contacting the clypeal margin (13-1), subalar line present but not specially modified (28-1, inter- preted as a reversal when hypothesized as a synapomorphy), and larval mandibles with a re- duced number of apical teeth (85-1). One other way to summarize the results of these analyses is to consider the performance of indi- vidual characters. Apart from autapomorphies (either at the level of terminal taxa or of the Apoidea as a taxon), which can never support conflicting phylogenetic hypotheses, there are some characters that consistently support the same hypotheses in all analyses, and others that perform quite erratically. The successive approximations character weight- ing procedure takes this into account by assigning weights to characters according to their level of homoplasy in a parsimony analysis. Consequently, one way to summarize a complex body of informa- tion about character performance in a series of parsimony analyses is to compare the final weights assigned to each character in each analysis. Table 8 provides such a summary for the characters used in this study. DISCUSSION In the title of this paper, I have described this study as "exploratory" . It is based upon definitions of characters and character states that are not well suited for cladistic analyses because they confound two different ways of thinking about character evolution, viz. homology and degree of divergence from an ancestral condition. Both types of character change are clearly part of evolution, but in order to properly describe either one, it is important to distinguish between them. In their tables, Evans, Bohart, and Menke treat all derived character states as equivalent, even in cases where it is very unlikely that they consider them homologous. For example, Bohart and Menke's definition of character states for the mouthparts (their Table 2, p. 30) is "mouthparts short" (plesiomorphic) and "mouth- parts elongate or unusually modified" (apomorphic). If this is coded as a simple two-state character, as in Bohart and Menke's table, and used in a quantitative parsimony analysis, one is hy- pothesizing that the elongate mouthparts of Bembicini, in which the galea and glossa are lengthened but the stipes and prementum are relatively unmodified, are homologous to the elongate mouthparts of Philanthinae, in which the galea and glossa are short but the stipes and prementum are lengthened. Bohart and Menke did not intend their table to be interpreted in this way (A.S. Menke, personal communication), and my analysis makes some preliminary attempts to redefine their characters in a way that comes closer to identifying similarities that are likely to be ho- mologous. However, there is a great need in sphecid systematics for careful comparative morphological studies such as the work on bee mouthparts that has been published in recent years, which has had the explicit goal of identifying homologous char- acter states (Winston 1979, McGinley 1980, Michener and Brooks 1984; also see Bohart and Menke 1976 p. vii). Neither a cladist nor an evolutionary taxonomist ever knows with absolute certainty whether or not a given shared similarity is really a synapomorphy. This is why parsimony analyses are done (Farris 1983). However, it does seem likely that a character analysis explicitly intended to distinguish between homologous and homoplastic similarities might do so more effectively than a character analysis that considers both types of similarity equally in- formative. A parsimony analysis utilizing the data that are supposed to form the basis of our existing Volume 1, Number 1, 1992 39 Table 9. Descriptive statistics for the weights assigned to each character by the successive approximations procedure in Analyses 1-9. Characters marked with an asterisk were not used in Analysis 9. Weight Character Mean Median Range 0. Ocelli 0.89 0 0-2 1. Inner margins of eyes 0 0 always 0 2. Eye facets 0.89 1 0-2 3. Elongated stipes 0.56 1 0-1 4. Galea-glossa complex 1 1 always 1 5. Mandibular socket 0.44 0 0-1 6. Labrum 3 3 always 3 *7. Mandibular notch 5 5 0-10 8. Tripartite clypeus 10 10 always 10 9. Shape of clypeus 3.67 3 3-5 *10. Gulararea 10 10 always 10 11. Frontal carina 10 10 always 10 *12. Frontal sulcus 2.50 0 0-10 13. Antennal sockets 1.33 1 1-2 14. Subantennal sclerite 2.78 2 1-4 15. Male clypeal brush 9.11 10 2-10 16. Propleuron 4.56 3 2-10 17 Pronotal collar 2.67 3 1-4 18. Pronotal lobe 0 0 always 0 19. Notauli 0.89 0 0-2 20. Admedian lines 3 3 always 3 21. Oblique scutal carina 6.44 10 1-10 22. Scutellum 10 10 always 10 23. Metanotal squamae 10 10 always 10 *24. Scutellar sulcus 0 0 always 0 *25. Episternal sulcus 0.13 0 0-1 26. Omaulus 0.44 0 0-2 27. Postspiracular carina 1 1 always 1 28. Subalarline 1.33 1 0-3 *29. Separation of midcoxae 0.88 1 0-1 30. Metasternum 5.89 1 0-1 "31. Precoxal lobes 2.63 2 1-4 32. Midcoxal carina 0.33 0 0-1 *33. Lower metapleural area 0.75 0 0-2 34. Propodeal sternite 3 3 always 3 35. Propodeal enclosure 4.67 5 3-10 36. Propodeal mucro 10 10 always 10 37. Propodeal spines 0.44 0 0-2 38. Tarsal claw 1.67 2 1-2 *39. Plantulae 0 0 always 0 40. Setae on hindtarsomere V 10 10 always 10 *41. Female foretarsal rake 0 0 always 0 42. Tarsomeres 0 0 always 0 43. Midtibial spurs 1 1 0-2 44. Apex of hind femur 4 2 0-10 *45. Insertion of metasoma 10 10 always 10 46. Metasomal petiole 2 2 always 2 *47. Basal carina on S 1 2.13 2 1-3 48. Shape of sternum 2 6.67 4 4-10 *49. Lateral line on Tl 2.75 3 1-3 50. Male metasomal segments 10 10 always 10 51. Female pygidial plate 0.67 1 0-1 52. Female sternum 6 7.78 10 5-10 53. Apex of female metasoma 0 0 always 0 54. Malecerci 0.33 0 0-1 55. Maletergum7 7.78 10 0-10 56. Volsella 1 1 always 1 57. Teeth on penis valves 4.11 3 1-10 58. Apex of marginal cell 0 0 always 0 59. Submarginal cells 0.44 0 0-1 60. Forewing vein 3rs-m 0 0 always 0 *61. Forewing vein 2-Rs 0.38 0 0-1 62. Number of discoidal cells 10 10 always 10 *63. Forewing vein M 6.75 10 1-10 64. First submarginal cell 4 4 always 4 65. Vein Rs + M 10 10 always 10 *66. Jugallobe 1.25 1 0-3 *67. Hind wing vein 2A 2.50 2 2-4 *68. Hind wing vein 3A 5.13 3 1-10 69. Plumose hairs 10 10 always 10 70. Female tergum 7 10 10 always 10 71. Female hind basitarsus 10 10 always 10 72. Larval provisions 10 10 always 10 73. Pronotum (posterolateral) 10 10 always 10 74. Pronotum (ventral angle) 10 10 always 10 75. Metapostnotum 10 10 always 10 *76. Hindtibial strigilus 2.25 2 2-4 77. Pronotum (hind margin) 10 10 always 10 78. Presternum 10 10 always 10 79. Larval integument 7.20 10 3-10 80. Larval body shape 4 4 always 4 81. Position of larval anus 7.60 10 4-10 82. Larval spiracles 5.20 4 4-10 83. Larval parietal bands 1.80 2 1-2 84. Larval antennal papillae 1.80 2 1-2 85. Larval mandibles 3.20 3 2-4 86. Larval maxillae 3.60 4 2-4 87. Larval galea 6.40 4 4-10 88. Larval spinnerets 5 5 always 5 89. Male sternum 7 2.11 2 1-4 Autapomorphies of Apoidea: 18, 73, 74, 75, 77 Autapomorphies of terminal taxa: 8 (Palarini), 23 (Oxybelini), 36 (Oxybelini), 65 (Oxybelini) phylogenetic hypothesis will reveal which charac- ters support that hypothesis and which do not. As in any scientific investigation, further analysis can then be done to try to reconcile the conflicting evidence from the initial study. It is also worth remembering that the groundplan states assigned to the hypothetical ancestor by the analytical procedure developed by Maddison et al. (1984) depend upon the validity of the phylogenetic hypothesis derived from the work of Brothers (1975) and Carpenter (1990). This is more than a trivial truism because the procedures that Brothers used to polarize characters in his analysis were, insofar as one can judge from his paper, essentially the same as those employed by Bohart and Menke. One respect in which his outgroup comparisons 40 Journal of Hymenoptera Research may have differed from those of Bohart and Menke and Evans is that he seems to have placed special emphasis on a putative sister group of the Aculeata, the family Trigonalyidae (Brothers 1975 p. 491). The analyses presented in this paper show how sensitive phy logenetic hypotheses can be to polarity decisions for only a few characters in a data set, if that data set has high levels of character conflict. Until cladistic relationships among the major hy- menopteran lineages are more completely under- stood, assigning groundplan character states for the Apoidea will remain problematic. This, in turn, will contribute to the difficulty of determining cladistic relationships within the Apoidea. In my opinion, it is premature to propose any changes in the higher level classification of Apoidea on the basis of these analyses. I have nothing substantive to add to the long-standing debate about the merits of phenetic, cladistic, and more traditional classifications that attempt to combine cladistic and phenetic information. However, I will state for the record my preference for strictly cladistic classifications, in which only monophyl- etic (or holophyletic) groups are recognized and there is a direct correspondence between the clas- sification and the branching pattern of phylogeny. Lomholdt's (1982) classification of sphecid wasps and bees is the only one known to me that has had these goals, but the analyses described in the present paper do not support the phylogenetic hypothesis upon which Lomholdt's classification is based. Indeed, my analyses demonstrate that no well- corroborated phylogenetic hypothesis for the sphecid wasps is yet available, so the necessary framework for a stable cladistic classification is also not yet available. I do not consider the development of a sound phylogenetic hypothesis to be an unattainable goal, but the type of character analysis necessary to achieve this goal remains to be done. The major utility that I see for the analyses presented here is that they provide a starting point for studies aimed at developing a more rigorously formulated and more stable phylogenetic hypothesis upon which to base a classification. In particular, where monophyletic assemblages of tribes can be identi- fied (Table 7), one can proceed to study relation- ships within these groups. For example, I have done such an analysis at the genus level for the "Philanthinae sensu stricto" of Table 7 (Alexander, 1992). Long-recognized groups whose monophyly is not supported by the evidence considered in this paper (see Table 8) should be examined to deter- mine if evidence for their monophyly has been overlooked or misinterpreted. A long-standing and conspicuous disagreement about the higher level classification of sphecid wasps and bees centers upon the issue of which taxa should be assigned the rank of family (for example, compare Bohart and Menke 1976 with Krombein 1979). Cladists and evolutionary tax- onomists use different criteria to resolve questions about taxonomic rank, and I will restrict myself to a consideration of rank from a cladistic perspective. Taxonomic rank in a cladistic classification simply indicates position in a branching sequence, and does not imply anything about overall phenetic similarity among taxa sharing the same rank. In a cladistic classification, a single family Sphecidae comprising all the Apoidea that are not bees is unacceptable, because it is clearly a paraphyletic group. If it could be shown that all of the taxa recognized as subfamilies in Bohart and Menke's classification are monophyletic, and that they are arrayed in a perfectly pinnate branching sequence, each taxon could be assigned the rank of family according to the sequencing convention of Nelson (1972). A different typeof branching pattern would require a different combination of families and subfamilies. However, with our present dim un- derstanding of phylogenetic relationships, it is unclear which of the groups of sphecid wasps that some recognize as families and others as subfami- lies are even monophyletic, let alone what branch- ing pattern links monophyletic groups. Tables 7 and 8 indicate that the evidence regarding the monophyly of these groups is mixed. From a cladistic perspective, the "one family vs. many families" debate over sphecid wasps amounts to a choice between a single family Sphecidae that is clearly paraphyletic or a mixed assemblage of smaller families, of which some are probably monophyletic and others not. The monophyly of bees is strongly supported, but the appropriate rank to assign them in a cladistic classification depends upon the branching pattern among the Apoidea that are not bees. This is not a satisfactory situation. It is a problem that needs to be ad- dressed, if our classification is to serve as a powerful analytical tool rather than a source of confusion in our attempts to understand these beautiful and fascinating insects. Volume 1, Number 1, 1992 41 ACKNOWLEDGMENTS I am especially grateful to Arnold Menke for generous help and advice at all stages of this study, from helping with initial planning, to reading several drafts, to making patient and polite but persistent appeals for a final manuscript. Other colleagues during my stay on a Smithsonian Postdoctoral Fellowship at the U.S. National Museum of Natural History, especially Bryan Danforth, Karl Krombein, and Ronald McGinley, as well as Charles Michener at the University of Kansas, also provided valuable and much appreciated guidance. In addition to reading an early draft of the manuscript and arranging for my participation in the symposium on Hymenoptera phylogeny at the conference of the International Society of Hymenopterists in Sheffield, Denis Brothers first suggested that I include Heterogyna in my analysis. Mick Day kindly provided specimens of this genus. Although I depended primarily upon specimens from the U.S. National Museum of Natural History, I am also indebted to the following individuals and institutions for the loan of materials: California Academy of Sciences (W.J. Pulawski); Colorado State University (H.E. Evans, B. C. Kondratieff); Cornell University Insect Collections (E.R. Hoebeke, J. K. Liebherr); Museum of Comparative Zoology, Harvard University (J. M. Carpenter, D. Furth); Natural History Museum of Los Angeles County (R.R. Snelling); Snow Entomological Museum, University of Kansas (J.S. Ashe, R. L. Brooks); USDA- ARS Bee Biology and Systematics Laboratory (T.L. Griswold). LITERATURE CITED Alexander, B.A. 1990. A preliminary phylogenetic analysis of sphecid wasps and bees. Sphecos 20: 7-16. Alexander, B.A. 1992. A cladistic analysis of the subfamily Philanthinae (Hymenoptera: Sphecidae). Systematic Entomology 17: 91-108. Bohart, R.M. and A.S. Menke. 1976. Sphecid wasps of the world. University of California Press, Berkeley, ix + 695 pp. Brooks, DR. and D.A. McLennan. 1991. Phylogeny, ecology, and behavior. The University of Chicago Press, xii + 434 pp. Brothers, D.J. 1975. Phylogeny and classification of the aculeate Hymenoptera, with special reference to Mutillidae. University of Kansas Science Bulletin 50: 483-648. Carpenter, J.M. 1986. Cladistics of the Chrysidoidea (Hymenoptera). Journal of the Neu'York Entomological Society 94: 303-330. Carpenter, J.M. 1988. Choosing among multiple equally parsimonious cladograms. Cladistics 4: 291-296. Carpenter, J.M. 1990. On Brother'saculeate phylogeny. Sphecos 19:9-10. Day, M.C. 1984. The enigmatic genus Heterogyna Nagy (Hymenoptera: Sphecidae; Heterogyninae). Systematic Entomology 9: 293-307. Evans, H.E. 1957a. Studies on the comparative ethology of digger wasps of the genus Bembix. Comstock Publishing Associates, Ithaca, NY. 248 pp. Evans, H.E. 1957b. Studies on the larvae of digger wasps. Part III. Philanthinae, Trypoxyloninae, and Crabroninae. Transactions of the American Entomological Society 83: 79-1 17. Evans, H.E. 1958. Studies on the larvae of digger wasps. Part IV: Astatinae, Larrinae, Pemphredoninae. Transactions of the American Entomological Society 84: 109-139. Evans, H.E. 1959. Studies on the larvae of digger wasps. Part V: Conclusion. Transactions of the American Entomological Society 85:137-191. Evans, H.E. 1962. The evolution of prey-carrying mechanisms in wasps. Evolution 16: 468-483. Evans, H.E. 1964a. The classification and evolution of digger wasps as suggested by larval characters. Entomological News 75: 225-237. Evans, H.E. 1964b. Further studies on the larvae of digger wasps. Transactions of the American Entomological Society 90:235-321. Evans, H.E. 1966a. The comparative ethology and evolution of the sand wasps. Harvard University Press, Cambridge, xvi + 526 pp. Evans, H.E. 1966b. The behavior patterns of solitary wasps. Annual Review of Entomology 1 1 : 123-154. Evans, H.E. 1966c. The accessory burrows of digger wasps. Science 152:465-471. Evans, H.E. and C.S. Lin. 1956a. Studies on the larvae of digger wasps. Part I: Sphecinae. Transactions of the American Entomological Society 81: 131-166. Evans, H.E. and C.S. Lin. 1956b. Studies on the larvae of digger wasps. Part II: Nyssoninae. Transactions of the American Entomological Society 82: 35-66. Evans, H.E. and R.W.Matthews. 1968. The larva of Microstigmus comes, with comments on its relationship to other pemphredonine genera. Psyche 75: 132-134. Evans, H.E. and K.M. O'Neill! 1988. The natural history and behavior of North American beewolves. Comstock Publishing Associates, Ithaca, NY. vii + 278 pp. Evans, H.E. and M.J. West Eberhard. 1970. The wasps. University of Michigan Press, Ann Arbor, vi + 265 pp. Farris, J.S. 1969. A successive approximations approach to character weighting. Systematic Zoology 18: 374-385. Farris, J.S. 1983. The logical basis of phylogenetic analysis, pp. 7-36. In Funk, V.A. and N.I. Platnick, eds. Advances in Cladistics, Vol. 2, Proceedings of the Second Meeting of the Willi Hennig Society. Columbia University Press, New York. Farris, J.S. 1988. Hennig86 reference, I'ersion 1 .0. Port Jefferson, New York. Gauld, I. and B. Bolton. 1988. The Hymenoptera. British Museum (Natural History) and Oxford University Press, xi + 332 PP- Grandi, G. 1961. Studi di un entomologo sugli Imenotteri supenori.Bolletinodeli Istitutodi Entomologiadeli Unwersita di Bologna 25:i-xvi, 1-659. Grimaldi, D.A. 1990. A phylogenetic, revised classification of genera in the Drosophilidae. Bulletin of the American Museum of Natural History, No. 197. 139 pp. Harvey, P.H. and M.D. Pagel. 1991. The comparative method in evolutionary biology. Oxford University Press. 239 pp. Konigsmann, E. 1978. Das phylogenetische System der Hymenoptera. Teil 4: Aculeata (Unterordnung Apocrita). Deutsche Entomologische Zeitschrift 25: 365-435. Krombein, K.V.I 979. Superfamily Sphecoidea, pp. 1 573-1 740. In Krombein, K.V., P.D. Hurd, Jr., DR. Smith, and B.D. Burks, eds. Catalog of Hymenoptera in America North of Mexico, Vol. 2. Smithsonian Institution Press, Washington, D.C. Lomholdt, O. 1982. On the origin of the bees (Hymenoptera: Apidae, Sphecidae). Entomologica Scandinavica 13: 185-190. Maddison, W.P., M.J. Donoghue, and D.R. Maddison. 1984. 42 Journal of Hymenoptera Research Outgroup analysis and parsimony. Systematic Zoology 33: 83-103. Mason, W.R.M. 1983. The phytogeny of the Apocrita. (Unpublished, cited as "Mason, 1983a" in Gauld and Bolton (1988) and as "Mason, 1986b" in Carpenter, 1986). McGinley, R.J. 1980. Glossal morphology of the Colletidae and recognition of Stenotritidae at the family level. Journal of the Kansas Entomological Society 53: 539-552. McGinley, R.J. 1987. Apoidea, pp. 689-704. In Stehr, F.W., ed. Immature Insects. Kendall-Hunt Publishing Company, Dubuque, Iowa. Menke, A.S. 1988. Pison in the New World: a revision. Contributions of the American Entomological Institute 24(3): 1-171. Michener, CD. 1944. Comparative external morphology, phylogeny, and a classification of the bees (Hymenoptera). Bulletin of the American Museum of Natural History 82(6): 151- 326. Michener, CD. 1952. A note on the larvae of sphecid wasps. Journal of the Kansas Entomological Society 25(3): 115-116. Michener, CD. 1974. The Social Behavior of the Bees. Harvard University Press, Cambridge, Massachusetts. 404 pp. Michener,CD. 1986. Family-group names among bees. Journal of the Kansas Entomological Society 59: 219-234. Michener, CD. and R.W. Brooks. 1984. Comparative study of the glossa of bees (Apoidea). Contributions of the American Entomological Institute 22: 1-73. Nagy, C.G. 1969. A new taxon of the family Heterogynidae Latreille (Hym., Acu\eata). Entomologische Mitteilungen aus dem Zoologischen Museum Hamburg 64: 7-12. Nelson, G.J. 1972. Phylogenetic relationship and classification. Systematic Zoology 21: 227-231. Nixon, K.M. 1991. Clados reference, version 1.0. Trumansburg, New York. Pate, V.S.L. 1938. Studies in the nyssonine wasps (Hymenoptera: Sphecidae). IV. New or redefined genera of the tribe Nyssonini, with descriptions of new species. Transactions of the American Entomological Society 64: 117- 190. Watrous, L.E. and Q.D. Wheeler. 1981. The outgroup comparison method of character analysis. Systematic Zoology 30: 1-11. Winston, M.L. 1979. The proboscis of the long-tongued bees: a comparative study. University of Kansas Science Bulletin 51:631-667. APPENDIX 1: TAXA EXAMINED For the ingroup, species selected for studies of adult morphology were those used in Evans' studies of sphecid larvae, plus exemplars from tribes whose larvae have never been described. OUTGROUP ICHNEUMONOIDEA Ichneumonidae:E*t'n'sft'S roborator, E. comstockii, Pimpla aequalis, Scambus brevicornis Biaconidae-.Doryctes spp., Spathius spp., Helcon spp. CHRYS1DOIDEA Plumariidae: Plumaroides andalgalensis, Plumarius sp., Myrmecopterina sp. Bethylidae: Epyris coriaceus, E. clarimontis, Anisepyris aurichalceus, A. subviolaceus , Pristocerus armifera Scolebythidae: Clystopsenella longiventris VESPOIDEA Sierolomorphidae: Sierolomorpha ambigua, S. canadensis, S. nigrescens, S. similis Rhopalosomatidae: Rhopalosoma nearcticus, Olixon banksii Pompilidae:/4wf)/opHS (Lophagenia) erigone, Episyron biguttata, Priocnemoides fulvicornis Anthoboscinae:Lfl/fl;ia lusa, Plesiomorpha albinervis, Cosila chilensis, Anthobosca madecassa INGROUP Andrenidae: Andrena thaspii, Calliopsis andreniformis Halictidae: Halictus rubicundus, Augochlora pura, Dufourea marginata, Nomia notiomorpha Melittidae: Melitta ieporina Colletidae: Hylaeus basalis, Colletes wootoni Anthophoridae: Exomalopsis albata Megachilidae: Ashmeadiella californica, Megachile texana Ampulicini: Ampulex canaliculata Dolichurini: Dolichurus corniculus Sceliphrini: Sceliphron caementarium , S. assimile, S. spirifex, Chalybion californicum, Chlorion aerarium, Podium rufipes, P. flavipenne, P. luctuosum Sphecini:Pn0wy.r atratus, P. thomae, Isodontia mexicana, I. philadelphica, I. auripes,!. elegans, Palinodes dimidiatus, Sphex ichneumoneus, S. pensylvanicus, S. argentatus, S. tepanecus \mmophi\inr.Podalonialuctuosa,P.tydei,P.robusta,Ammophila procera, A. urnaria, A. harti, A. juncea, A. campestris, A. aberti, A. placida, A. pruinosa, A. fernaldi Dinetini:Dinefus pictus Astatini: Astata unicolor, A. occidentals, A. minor, A. boops, A. bicolor, Dryudella immigrans Palarini:Pfl/«rus variegatus Miscophini:Miscophus bicolor, M.(Nitelopterus)evansi,M.(N.) slossonae barberi, Nitela spinolae, Plenoculus davisi, Solierella blaisdelli, S. peckhami, S. compedita Larrini: Ancistromma distincta, Liris haemorrhoidalus, Li. nigra, Larra analis, La. luzonensis, Tachytes aurulentus, T. crassus, T. distinctus, T. mergus, Tachysphex apicalis, Tx. costa, Tx. obscuripennis, Tx. nitidus, Tx. pompiliformis Trypoxylini: Pisonopsis birkmanni, Pison argentatum, P. atrum, Trypoxylon (Trypargilum) clavatum, T. (Tg.) collinum, T. (Tg.) politum, T. (Tg.) spinosum, T. (Tg.) tridentatum, T. (Tg.) texense, Trypoxylon (Trypoxylon) ashmeadi, T. (Tn.) figulus, T. (Tn.) frigidum, T. (Tn.) johnsoni Crabronini: Anacrabro ocellatus, Crabro advenus, Cb. argusinus, Cb.monticola,Crossocerusannulipes,Cs.capitosus,Cs.cinxius, Cs.fergusoni, Cs. nigritus, Cs. podagritus, Cs . quadrimaculatus , Cs. walkeri, Ectemnius atriceps, E. cavifrons, E. continuus, E. guttatus, E. paucimaculatus, E. sexcinctus, E. stirpicolus, E. tumidoventris, E. zonatus, Entomognathus brevis, Lindenius pygmaeus, L. tylotis, Moniaecera asperata, Rhopalum clavipes, R. coarctatum, R. pedicellatum, R. rufigaster, Tracheliodes amu, T. quinquenotatus Oxybelini: Oxybelusargentatus,0.bipunctatus,0.quadrinotatus, O. victor Volume 1, Number 1, 1992 43 Bothynostethini: Bothynostethus distinctus, Willinkiella argentina Scapheutini: Bohartella scapheutoides, Scapheutes brasilianus Laphyragogini: Laphyragogus pictus Xenosphecini: Xenosphex timberlakei, X. xerophilus Entomosericini: Entomosericus concinnus, E. kaufmani Heliocausini: Heliocausus argentinus, H. fiebrigi Pemphredonini: Ammoplanus handlirschi, Arpactophilus steindachneri, Diodontus minutus, D. tristis, D. mrginianus, Microstigtmts comes, Passaloecus clypealis, Pa. corniger, Pa. cuspidatus. Pa. eremita, Pa. gracilis, Pa. insignis, Pa. pictus, Pa. singularis, Pemphredon (Cemonus) gennelli, Pe. (C.) inornatus, Pe. (C.) lethifer, Pe. (C.) rugifer, Pe. (C.) wesmaeli, Pe. (Ceratophorus) morio, Pe. (Pemphredcm) concolor, Pe. (P.) lugens, Pe. (P.) lugubris, Spilomena enslmi, SHgmusfraternus, St. inordinatus, St. pendulus, St. solskyi Psenini: Mimesa bicolor, Mimumesa nigra, Pluto albifacies, Psen ater, Psen bakeri, Psen simplicicornis, Psenulus fuscipennis, Psenulus pallipes Mellinini: Mellinus arvensis Alyssonini: Alysson melleus, A. cameroni, Didineis latimana Nyssonini: Epinysson basilaris, Nysson daecki, N. trimaculatus Gorytini: Gorytes canaliculars, C. pleuripunctatus, Hoplisoides costalis, H. hamatus, H. placidus nebulosus, Ochleroptera bipunctata, Oryttus gracilis, Sphecius speciosus Stizim.Bembecinus mexicanus, B. neglectus, B. tridens, B. quinquespinosus, Stizoides unicinctus, Stizus pulcherrimus Bembicini: Bembix amoena, B. belfragei, B. cameroni, B. cinerea, B. comata, B. hinei, B. integra, B. multipicta, B. nubilipennis, B. occidentalis, B. oculata, B. olivacea, B. pallidipicta, B. sayi, B. spinolae, B. texana, B. troglodytes, B. dentilabris, Bicyrtes fodiens, B. quadrifasciata , B. ventralis, Glenostictia pulla, G. scitula, Microbembex monodonta, Rubrica nasuta, Steniolia duplicata,S.elegans,S. longirostra.S.obliqua, Stictiellaformosa, S. pulchella, S. serrata, Stictia Carolina, S. heros, S. signata, S. vivida Eremiaspheciini: Eremiasphecium desertorum, E. schmiedeknechti Odontosphecini: Odontosphex paradoxus Pseudoscoliini: Pseudoscolia dewitzi, P. pharaonum, P. theryi, P. tricolor Aphilanthopini: Aphilanthops foxi, A. frigidus, A. hispidus, A. subfrigidus, Clypeadon bechteli, C. californicus, C. dreisbachi, C. evansi, C. haigi, C. laticinctus, C. sculleni, C. taurulus, C. utahensis, Philanthinus integer, P. quattuordecimpunctatus Philanthini: Plulanthus albopilosus, P. barbiger, P. bicinctus, P. bilunatus, P. coarctatus, P. coronatus, P. crabroniformis, P. gibbosus, P. politus, P. solivagus, P. triangulum, Trachypus mexicanus, T. petioiatus Cercerini: Cerceris angular is, C. clypeata, C. flavofasciata floridensis, C. frontata frontata, C. fumipennis, C. nigrescens, C. robertsoni robertsoni, C. r. emmiltosus, C. rubida julii, C. sabulosa, C. quinquefasciata, Eucerceris bitruncata, E. flavocincta Heterogyna: H. botswana.H.fantsilotra.H. madecassa.H.protea APPENDIX 2 On a strict consensus tree, polytomies usually mean that there are numerous equally parsimonious arrangements of the taxa involved in the polytomy. This creates difficulties for one wishing to present the evidential support for a consensus tree by mapping the distribution of character states upon the tree. It has even been argued that character states should not be mapped onto consensus trees (Nixon 1991). The following simple example is intended to explain how one might interpret the distributions of character states on the polytomies in the consensus trees in this paper. The simplest possible polytomy would involve three taxa and three characters. There are three possible cladograms for three taxa, and in this example each of the possible trees is supported by one character (a "1" in the data matrix represents the apomorphic character state). A strict consensus tree for this data set would be an unresolved trichotomy. The cladograms show how characters are distributed on each of the three equally parsimonious cladograms (all three cladograms have a length of 5 steps). If characters are mapped onto the strict consensus tree, each terminal taxon is depicted as having two autapomorphies, whereas in each of the fully resolved cladograms only one terminal taxon has two autapomorphies. In general, whenever two or more taxa involved in a polytomy on a consensus tree share a derived character state, that character state can be interpreted as a synapomorphy in one or more of the equally parsimonious cladograms that are represented by the polytomy. For example, characters 1 3, 14, and 1 5 in Fig. 1 A are depicted as autapomorphies for the taxa Aphilanthopini, Philanthini, and Cercerini. Fig. 1 A is a consensus tree for 5,272 equally parsimonious cladograms, and on many of these cladograms characters 13-15 would be synapomorphies for a monophyletic group containing the tribes Aphilanthopini, Philanthini, and Cercerini. 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X > c o c C 3 T) 60 c fO g — J3 3 be ■0 u A is in (-1 tf> 32 > 2 ™ a c 43 < u 1- c 0 \D in ro u"> ^r 3Vailll13U- S339 a3n9N0i-9N0l' o o o o INIZI1S ' INDiaW39- O CM CM CM III I CM CM J3VfO-fM I I vOMDinLno-ivOThoo INH39AX0- iNiNoagvao-^J INIbHdH33S INID3HdS — 7 ^CMO N in *t m ro — v INIIIHdOUIWV CD rOCM ro ro *- 1 <£> T tO cop^jD^rcDr^cNi — o\r^>jDi/iroooDLnvcMun iDiDiD-DinifiinifiV ^r ^~ m~ 'n" m~ intotoM INI1AU09' o* ro cm o r^ ^o ■— CO T fOfOCMCN CM v r- en n~ «- o cd miunU'Miftfl in v |Q ro ro cm -- (m0 cmooooocmcm oo o>\Dr~-oi— ocom — comcNocD\oin,rcj»r^ co id m in in m ^r VTK)ioroi— o .— CO vO >J3 Lf> ^J NrrOrorOCMCMCMCNCNCN — INId33d33 CO'DlN^'CNC^i/)'? ro •" in m INIHlNVllHd- INIdOHlNVUHdV ro«-r^o\c\imN"roLom' ini/i^T'Ofo---- cooxn miio in ro ro <- «- •— ' ININ0SSA1V UDv£)NTCNOCO*OmT I sO LOTfOrOCNCNCMCMO INIlAXOdAdl iO \fl — — 0> O CD s£)LO inTfOK) CM vD - INIijdVl iO CO >0 CT O \D I \OLOLDCNCN^CJ*r- CNO INIHdODSIW INIdVlVd ININm3UI INI1V1SV < 00 CO >- _J < z < rO — COLOfOCMCJ'CDLOO^COr^ T^'rOMtOIOCNCNCN^'-"- r^r^r^r^r^-^OLO i n" i 1 1 r. on iO Ml on N~ 1 vO in to in '■j CM CJ\ CO r- ro o o CM CM o o O O o .-> y*i ^r ro IN in cm o r> £> vO 'i 'J NT ■I '■■I to ro ro CM N* O o CM r^ CO vO N" ro *- j- 'T 1 ■j •J CM CM CM ' 3Sc CM o o — o ,_ n* M~ 3d H JUI 3c j. vo in M tn CM If) o o O o tO \T r> vfl co n" ro CT r- vO *D \0 in in ^r ro ro (N rji Volume 1, Number 1, 1992 55 avauonvH- 3vaii3moD- 3vai.Lj.n3w S339 a3fl9NOJ.-9NO"f 'OM-0!P ■ INIHlNVIIHd- INIdOHlNVIIHdvJ ININOa3dHdW3d- — O* — iD(Dr«-^)P0{S|O, •O vO *D l/> V ININ0daVd3 • INHAXOdAdl ■ INIHdODSIU ■ •o ro c* m ~o o* 10 o* r~ oi 03 i — o - < Z < 3 o- 01 a o c o o o. 3 C o c c 3 J3 ININI 113UI " >0 Kl — \D T • C 1/3 C* 03 j«1T MO E10*««10T tOU)» . ■3 a « 2 C fl5 < -C In U in c 3 X s s § « U a; — > in g .O 3 . * 60.-. E S 56 Journal of Hymenoptera Research iNinoosoanasd- INIdOHlNVIIHdV- INIHlNVllHd - INIID3HdSVIU3d3- ININOa3dHdW3d ■ INI90DVdAHdV1- 3VaiN3daNV- avauonvH- 3vaii3moD- WIO fv, WV S339 fig' 03n9N01-9NOV •- cn a* r«- in © INI33HdS01NOaO INHAXOdAdi • iNiNoagvdD- 0« i A ^> MiMD vS in Kl CM CM CM CM CMCM*1 •°" ° mnaaAxo INIin3Hd¥3S- INIH131S0NAH10a- oincMJ,;, INI13Nia- INDId3SOW01N3- -2 o to tn INIlAd09 o o o ■» iDvO — a* in ■- o •- i ioin^'CN(N(Nr-i'-CN in n>fN z II ■ o 0> IO CN tn >D 1 o — n>>o T CN ■— o> o* r- to r- in V — MO CM — ■D in in < z < r~ — in c/i p« V^-0>r*i(M^p INID3HdSON3X- INID3HdS INHIHdOUUIV — _ oo r~- m to r-. >o in in k> ~- Volume 1, Number 1, 1992 57 INID3HdSON3X ■ iNinoDSoanasd- INIdOHlNVIIHdV- 3TOi Oi CN lO INI909VtiAHdVl ■ )iomwiM/ii' 3vaiN3aaNv- avaiionvH- 3vaii3moD- S339 c o vo Q3n9N01-9NCn - 3vauin3u- INID3HdS01N0a0- — o> — V ININOa3MHdUI3d- INllD3HdS¥IW3d3 INIHdODSIUI - •& in u 2 O a* £D V r- r — >o in in in v in — ojj v (-io* < Z < ^ — CD — C*CN 03 to in cj, c^ in r^ o* v — o cd — OCT'(D^'vorsir«-Oir«-o i aiCDr-iooaprootn-o^' INIDSHdS INMIHdOWUIV V — CO 3 C « n J3 t/i C o u (A rn s X rx o bt ft. ft. A m 58 Journal of Hymenoptera Research avaiNaaaNv - avauonvH- 3vauano3- 3vauin3w — S338 _i_ asnsNoi-SNOT INI909VMAHdV3- INIHlNVIIHd- INIdOHlNVIIHdV- iNinoDsoanssd- INId33a3D- INIDSHdSOlNOOO- Uini03HdSVIU3a3 ■ !NID3HdSON3X- INHAXOdAai • iNiNoaavao- INH3aAX0 ■ I/) * O r-. * IO (VlOrr iNiNmaw- ININ0SSA1V. INiaVlVd ■ INIH131SONAH109- INIinSHdVDS- ININOa3dHdW3d ■ INI3I9U39 INIZI1S vO ^T fO — CM t I INIDIcJ3SOW01N3- INISnVDOI13H- < CO < < T — as cm 1NI1V1SV- co ro cm r* lolo , m , T INIllHdOUIUIV ' — cd aj INIdHdll33S- ^ >OT « O a) ™ifi in Volume 1, Number 1, 1992 59 d tr> tn in »o v ki o zvcovij-ajVf' INDIM3SOUI01N3 ■ iNisnvDonaH- -> JD o> r^ — O - CL ° *J* ? < o » "T o^ r- — 1 r«0 O^ (D f, r^ 3(ON lO M (\| O, ? 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P Ut a. a. -! tfl C > C o 01 u 3 CA E ■a T-, o a w u u. 0i Volume 1, Number 1, 1992 61 INID3HdSON3X- ININJSd-2^ iNinoDsoanasd- INIdOHlNVIIHdV — INIHlNVllHd 3vaiN3daNv- 3vauonvH - S339 a3nDNoi-SNoi ■ ININOCHdHdWd- INIID3HdSVIU3d3- > UD tO 00 © [^ * INHAXOdAdJ. ININOdaVdD ) ^ gd r^>o poojo iNnaflAxo- INIJ.n3HdV3S ■ INIH131S0NAHJ0B """ " INIZIJ.S - lf>V O^IOUT C INI3ld350U01N3- iNisnvoonjH- •o >o — o> i/i — c INI909VdAHdV~l- iNianHDnoa ■ — o and terga; CQarse synonymy. on lower mesopleuron; propodeum cross-ridged Female. — Length 6 mm. Black, tegula, post- laterally, ridged to areolate posteriorly. Clypeus tegula, T-VI or V-VI, red; metanotal squamae, sub- with a bevel, flanked by a stout tooth. LID 1 .6x eye apical bands on T-I to V, those on I to IV separated breadth; metanotal squama rather broad, point medially, yellow; eyes brown; wings lightly stained. lateral; propodeal mucro strong, incurved beneath, Volume 1, Number 1, 1992 159 1. cordatus 4. mimeticus 7. marginellus 11. tarapacae 5. penai 8. tarapacae 3. chilensis 6. clandestinus 9. toroi 13. joergenseni 14. tarapacae Figs. 1-9, Squamae and mucro, females. Figs. 10, 11, Femorotibial area, outer view, females. Figs. 12, 13, Clypeus, males; 13a, White beard. Fig. 14, Terga, female, dorsal. Figs. 4, 5, 8, 9, 10, 11, 14, Holotypes. Fig. 12, Paratype. Figs, not drawn to scale. 160 Journal of Hymenoptera Research notched apically (Fig. 3); hindfemur with a strong apicodorsal crest (as in Fig. 10); pygidial plate angled about as in Fig. 14. Male.— Length 4.5-6 mm. T- VI- VII or V to VII red; T-II to VI with lateral teeth. Distribution. — The 12 males and 1 1 females that I have seen are from the Chilean provinces of Coquimbo: Rivadavia, Las Breas; Valparaiso: Las Penas, Salinas; Santiago: Santiago, Las Condes, El Canelo; Colchagua: Camino a Termas del Flaco; Concepcion; Malleco: Lago Icalma, La Fusta Mts., Lago Galletue. Systematics. — Oxybelus chilensis is one of the more abundant species in central Chile. The brown eyes; nearly all black mesonotum; red tegula, post- tegula, and terminal terga; and stout but not ex- panded mucro are found also in mimeticus and penai. O. chilensis differs from the former species by its more laterally pointed squamae, more extensive tergal maculation, and all dark male midtibia. The coarse vertical ridging of the mesopleuron and extensive silvery pubescence are distinctive mpenai and will separate it from chilensis. Both sexes of penai have the lower mesopleuron with silvery hair. In chilensis this area is coarsely punctate and not sil- very appressed. The poorly described type of comatus has not been located and may be lost. The synonymy of comatus is based on a specimen of chilensis in the British Museum determined by Reed as comatus. Oxybelus clandestinus Kohl Oxybelus clandestinus Kohl 1905:358. Lectotype female (here designated), Concepcion, Concepcion Prov., Chile (VIENNA). Female. — Length 6 mm. Black, antenna beneath and apically, mandible medially, pygidial plate apically, reddish; mandible to near base, tegula, post-tegula in part, tibiae basally (extended on foretibia), squama, apicolateral streaks on T-I-II (broken medially) pale yellow; eyes gray; wings very lightly stained. Pubescence silvery appressed on lower half of face, gena, mesopleuron (weak), tergal apices, and pygidial plate. Punctation mostly fine and close, a little more coarse on mesopleuron; propodeum with cross-ridging laterally and posterolaterally, broadly areolate toward base be- low metanotum. Free clypeal margin nearly straight, not beveled, a tooth at outer fifth, a small knob on clypeus medially; LID 1.2x eye breadth; metanotal squamae small, posteriorly pointed, broadly disconnected; propodeal mucro narrow, tapering to a slightly rounded apex (Fig. 6); py- gidial plate angled about as in Fig. 14. Male. — Length 5 mm. No lateral tergal teeth, LID l.lx eye breadth, T-I only with lateral streak or all T-I to VI dark, T-VII reddish on apical half. Distribution. — I have seen 7 males and 2 females from the following Chilean Provinces: Nuble: Termas de Chilian, 1-27-67 (M. E. Irwin), Concepcion (type female and male). Malleco: La Fusta Mts., II- 21-62 (L. E. Pena); Curacautin 3 km.s., 1-14-89 (L. S. Kimsey). Systematics. — The slender mucro, pointed squamae, mostly dark tegula and post-tegula, red apical half of last tergum, and gray eyes of museum specimens are characteristic. Oxybelus cordatus Spinola Oxybelus cordatus Spinola 1851: 364. Lectotype female (here designated), Chile: "provincias del norte, en Coquimbo, etc." (TURIN). Female. — Length 4-5 mm. Black, apical two- thirds of flagellum, tegula, post- tegula, legs partly, T-V usually, T-VII, reddish; mandible to base, pronotal lobe, squama, mucro around edge, femora toward apex, tibiae outwardly, lateral spots on T- I, lateral subapical streaks on T-II to IV, pale yellow; eyes gray, wings lightly stained. Pubescence silvery appressed on lower face, becoming yellowish above and brownish on vertex where it is erect but short; off-silvery hair on notum; silvery appressed on gena, mesopleuron, and tergal apices; pygidial setae yellowish. Punctation fine and close, propodeum mostly polished laterally, weakly sculptured posteriorly. Clypeus with free edge beveled across middle half, flanked by a sharp tooth, median knob obsolete; LID about equal to eye breadth; metanotal squama broad, point lat- eral; propodeal mucro flattened, about as broad as long, obtusely notched at apex (Fig. 1); hindfemur with a moderate apicodorsal crest; pygidial plate angled at 75°, unusually narrow at apex. Male. — Length 4-5 mm. Last flagellomere black, T-V to VII usually red, legs more extensively yel- low, mucro usually a little more narrow, T-II to VI with small lateral teeth, clypeal shape (Fig. 12). Distribution. This is the most abundant and widely dispersed of the Chilean Oxybelus. I have studied about 320 males and 120 females from the follow- Volume 1, Number 1, 1992 161 ing Chilean Provinces: Atacama, Coquimbo, Aconcagua, Valparaiso, Santiago, O'Higgins, Curico, Linares, Nuble, Bio-Bio, Malleco, and Aisen. Systematics. — Principal characters are the ex- tensive yellow leg markings, flat mucro which is short and broad as well as obtusely notched apically (Fig. 1), relatively simple male clypeus, and overall fine punctation. Oxybelus joergenseni Brethes Oxybelus joergenseni Brethes 1913: 141 . Holotype female (Type examined), Mendosa, Mendoza Prov., Argentina (BUENOS AIRES). Female. — Length 7 mm. Black, flagellum clypeal bevel, tegula, post-tegula, legs slightly, T-V-VI and associated sterna, red; mandible mostly, pronotum nearly all across, suctellar spots, squamae, apical femoral spots, subapical bands on T-I to IV, that on I enlarged laterally, yellow; eyes gray; wings nearly clear. Pubescence silvery appresed on lower face, gena, forefemur, mesopleuron; off -silvery on vertex, notum. Puctation moderately fine and close on vertex, notum; moderate and somewhat separated on shiny integument of upper face, mesopleuron; fine and close on terga, propodeum mostly polished laterally, weakly areolate posteriorly. Clypeus with free edge beveled across middle three-fifths, flanked by a sharp tooth, median knob present; LID about equal to eye breadth; metanotal squama longer than broad, point latera; mucro flattened, expanded medially, acutely notched at apex (Fig. 2); hind femur with strong apicodorsal crest; pygidial plate angled at about 80°; sides distinctly convex. Male . — Length about 5 mm. Last flagellomere dark, T-VI-VII red, tibiae and tarsi extensively yellow, free edge of clypeus with 3 teeth medially (Fig. 13), central one dividing a beard, T-III to VI with slender lateral teeth. Distribution. — Oxybelus joergenseni occurs widely in South America. The only Chilean mate- rial I have seen are 2 males from the U.S. National Museum. Data on the specimens are "Chile, R. C. Shannon." Systematics. — Characteristics of this species are the expanded mucro, convexly sided female py- gidial plate, red T-V-VI (female) or T-V to VII (male), tridentate male clypeus, red tegula and post-tegula, and complete yellow bands on T-I to IV. In addition it differs from other Chilean species by having pale markings on the pronotal ridge. Oxybelus marginellus Spinola Oxybelus marginellus Spinola 1851:365. Lectotype male (here designated), Chile (TURIN). Female. — Length 6.0-6.5 mm. Black, antenna weakly beneath, tegula and post-tegula, T-V at least partly, and pygidial plate, red; squama, basal tibial spots, lateral spots on T-I-II, lateral streaks on T-IV or absent, pale yellow; eyes usually brown; wings very lightly stained. Pubescence silvery ap- pressed on lower face, gena, and apical bands of T- I to IV; brownish erect hair on upper face, vertex, notum, and mesopleuron; golden are apical fringe of T-V and sparse setae of pygidial plate. Puncta- tion rather fine to moderate, a few larger punctures on mesopleuron above and on rather polished lower area; propodeum cross-ridged laterally, areolate posteriorly. Free clypeal margin toothed at lateral fourth, flanking a median beveled strip, a small knob on clypeus medially; LID 1.2x eye breadth, metanotal squama small, pointed; propodeal mucro clublike, gradually expanding to 1 MOD with hardly incised apex (Fig. 7); hindfemur without a prominent apicodorsal crest; pygidial plate angled about as in Fig. 14. Male. — Length 4.5-5 mm. Lateral teeth weakly developed on T - III to VI; erect hair on upper face, vertex, and mesopleuron pale; T-V to VII red; mandible sometimes partly yellow. Distribution. — Thirteen males, 4 females, from Chilean Provinces: Aconcagua: Los Riecello, 2800 meters, 1-20-74 (H. Toro); Santiago: Santiago (A. Faz), Las Condes, X-1953 (L. Pena) Canon del Plomo, XII-1988 (M. Fritz); Nuble: Termas de Chilian, I- 27-67 (M. Irwin); Malleco: Lago Icalma, 1-15-62 (L. Pena) , I-II-79 (0. Martinez), I-II-79 (Pasten), 1-12- 89 (L. Kimsey), Lago Galletue, 1-9-62 (L. Pena). Systematics. — The usually brown eyes of mu- seum specimens, slender but not spinelike mucro, basal tibial spots, red tegula and post-tegula, and brownish erect hair of the female upper face and vertex, characterize the species. Oxybelus mimeticus R. Bohart, new species Female holotype. — Length 7 mm. Black, tegula posteriorly, post-tegula inwardly, T-V-VI (VI yellowish), red; metanotal squama on outer half, weak basolateral dot on T-I, yellow; eyes mahogany red; wings nearly clear, venation dark brown. Facial pubescence silvery appressed below, erect and 162 Journal of Hymenoptera Research partly brownish above, pale on thorax (not appressed on mesopleuron), and laterally (not fringed) on terga. Punctation moderate and close on head, notum and terga, quite course and about 0.5 MOD on mesopleuron; genal area multiridged; propodeum partly cross-ridged laterally, coarsely posterolaterally and behind metanotum. Clypeus with a weakly impressed bevel, flanked by a stout tooth; LID much greater than eye breadth; metanotal squama with point posterior; propodeal mucro strong, twice as long as broad, incurved beneath, with a small apical notch (Fig. 4); hindfemur with a stout apicodorsal crest (Fig. 10); pygidial plate angled about as in Fig. 14. Male. — Length 5.5 - 6.0 mm. About as in fe- male; LID about 1. 3x eye breadth, T-I sometimes all black, midtibia and hindtibia sometimes with basal yellow dots, T-V to VII and associated sterna red; lateral teeth on T-II to VI well developed. Types. — Holotype female (American Museum of Natural History, NEW YORK), Chile, Atacama: 26 mi. s. Copiapo, X-19-69 (J. Rozen, L. Peha). Para types, 16 males, 2 females, Chilean Provinces: Atacama: Rio Pinte, 1400 m, II-2-67 (L. Pena, VALPARAISO); Paipote, X-12-71 (J. Rozen, L. Pena, NEW YORK); Tierra Amarilla, II-1-72 (W. Sielfeld, H. Toro, VALPARAISO); Los Loros, X-4-82 (E. Chiappa, DAVIS). Coquimbo: Las Breas, XI-78 (H. Toro, DAVIS) ; Balala, X-18-79 (L. Ruz), VALPARAISO; 5 mi. n. Laguna Dam, 8000 ft., XII- 6-50 (E. Ross, A. Michelbacher, SAN FRANCISCO), Rivadavia, X-29-57 (L. Pena, VALPARAISO). Santiago: Rio Clarillo, Cordillera, XII-1989 (L. Stange, GAINESVILLE). Systematics. — The stout and downcurved mu- cro occurs in penai, mimeticus, and chilensis. All of these have the mesopleural punctation close and rough. However, the first two have it exceptionally rough, and penai has vertical ridges and abundant silvery hair on the lower mesopleuron in addition. The squamae of mimeticus are moderately stout but have a strong posterior point. In the other two, the squamae are broader and the point is more lateral. Oxybelus penai R. Bohart, new species Female holotype. — Length 7 mm. Black, tegula, post-tegula, T-V-VI, red (pygidium only a little brown-tinged in a female paratype); pronotal lobe dully, basal dots on midtibia and hindtibia, lateral spots on T-I to IV, yellow; eyes brown; wings nearly clear. Appressed facial pubescence silvery, erect hair above pale but a little dark on vertex (much darker in paratypes); abundant, rather ap- pressed, somewhat shaggy silvery hair on gena, femora, and lower mesopleuron; pygidial setae pale golden. Punctation moderate and close on head, notum and terga; multiridging on gena (ob- scured by pubescence); mesopleuron with promi- nent dorsoventral multiridging; propodeum with strong lengthwise ridges laterally, cross-ridges posteriorly. Clypeus with a pronounced bevel, flanked by a weak tooth, a prominent median knob above; LID 1.6x eye breadth, face bulging toward middle; metanotal squama large, pointed laterally before posterior apex, propodeal mucro strong, twice as long as broad, incurved beneath, with a moderate apical notch (Fig. 5); hindfemur with a moderate apicodorsal crest; pygidial plate angled at 85°. Male. — Length 6 mm. As in female but silvery pubescence less prominent, T-V to VII red, T-II to VI with lateral teeth. Types. — Holotype female (Catolica Museum, VALPARAISO), Chile, Valparaiso Province, Concon, 11-1963 (Nunez). Paratypes, 36 males, 7 females, collected by L. Pena, L. Ruz, E. Reed, A. Faz, J. Lagunacelaya, E. Tosti-Croce, F. Rodriguez, H. Toro, and L. Kimsey. Provinces of paratypes are Atacama: La Junta; Coquimbo: Las Breas, Rivadavia; Valparaiso: Las Penas, Via del Mar, Olmue, Salinas; Santiago: Santiago, El Peumo, Pudahuel, El Canelo; Colchagua: Camino a Termas del Flaco; Curico: Los Quenes, Mt. Tonlemo; Talca: El Radal, 1100 m; Linares: Villego; Malleco: Conguillio National Park, Nahuelbuta; Chiloe: Los Quellon. Paratypes have been deposited in the museums listed in the introduction. The species is named for the well-known Chilean collector, Luis E. Pena. Systematics. — Related species, judging by the similar squamae and mucro, are mimeticus and chilensis. The vertical multiridging of the mesopleuron is distinctive. However, it may not be easily seen in some males, and there might be confusion with chilensis. In these cases the silvering of the lower mesopleuron in penai is differentiat- ing. From mimeticus the lateral rather than posteri- orly pointing squamae of penai, as well as the ex- tensive silvery hair of the female, are additional differences. Volume 1, Number 1, 1992 163 Oxybelus tarapacae R. Bohart, new species Female holotype. — Length 6 mm. Black, flagel- lum toward apex beneath, tarsi dully toward apex, tegula and post-tegula, T-V apically, T-VI and as- sociated sternum, red; large lateral spots on T-I-II, thin and broken subapical line on T-III, yellow (Fig. 14); wings a little stained; eyes brownish grey (browner in paratypes). Appressed facial pubes- cence silvery, that of vertex and elsewhere pale and scanty (erect on mesopleuron), pygidial setae red- dish golden. Punctation mostly rather fine and close, mesopleuron with longitudinal ridges, strongest on prepectus, lower mesopleuron mod- erately punctate, propodeum laterally almost all polished, cross-ridged posterolaterally, areolate below metanotum, terga a little polished between punctures. Clypeus with an obtuse bevel flanked by a small tooth; LID 1.5x eye breadth; metanotal squama small, posteriorly pointed, mucro finger- like, not sharply pointed (Fig. 8); hindfemur without an apicodorsal crest (Fig. 11); pygidial plate angled as in Fig. 14. Male. — Length 5 mm. T-VI and T-VII mostly red, no lateral tergal teeth. Types. — Holotype female (Catolica Museum, VALPARAISO), Chile, Tarapaca Prov.: Chusmisa, X-15-81 (H. Burgos). Paratypes (DAVIS), male, fe- male, Tarapaca Prov.: Chusmisa, 11-82 (P. Toro). Systematics. — The dark squama, relatively large yellow spots on T-I-II, and all dark legs, character- ize the species. Oxybelus toroi R. Bohart, new species Female holotype. — Length 5 mm; black, flagellum and tarsi mostly, tegula, post-tegula inwardly, terga V-VI and associated sterna, red; mandible medially, pronotal lobe, post-tegula outwardly, tibiae out- wardly, metanotal sqamae weakly, narrow sub- apical bands on T-I to V, that on V a little reddish, that on I slightly enlarged laterad, yellow; eyes gray; wings nearly clear. Appressed facial pubes- cence, erect vertex hair, appressed mesopleural pubescence, tergal fringes, pygidial setae, very slightly off-silvery. Punctation moderately fine and rather close on head, thorax and terga; propodeum with cross-ridging laterally and posterolaterally, broadly areolate toward base below metanotum. Clypeus with an obtuse median bevel, flanked by a sharp tooth; LID greater than eye breadth; metanotal squamae quite small and widely sepa- rated; propodeal mucro a slender spike (Fig. 9); hindfemur without an apicodorsal crest; pygidial plate angled at 85°. Male. — Length 4.0-4.5 mm. No lateral tergal teeth, LID only a little greater than eye breadth, T- VI- VII red, mandible yellow to near base, tibiae mostly dark. Types. — Holotype female (Catolica Museum, VALPARAISO), Chile, Antofagasta Prov.: San Pedro, 1-7-71 (W. Sielfeld). Paratypes, 4 males, 2 females, same data as type; other paratypes, Antofagasta Prov.: male, Chiu-Chiu, 1-24-72 (W. Sielfeld); female, Quillagua, X-12-81 (E. Tosti- Croce); male, Losana, IX-13-71 (L. Ruz); Tarapaca Prov.: Iquique, Quebrada de Chiza, II-II-89 (R. Miller, L. Stange). Paratypes have been deposited in the museums listed in the introduction. Systematics. — The spinelike mucro (so slender that it may be broken off in some males), tiny squamae (Fig. 9), narrow yellow tergal bands, and gray eyes of museum specimens, are characteristic. The species is named for Haroldo Toro, who furnished the majority of the specimens used in this study. LITERATURE CITED Bohart, R. M. and A. S. Menke. 1976. Sphecid Wasps of the World, a Generic Revision. University of California Press, Berkeley. ix + 695 pp. Brethes, J. 1913. Himenopteros de la America Meridional. Anales del Museo National de Buenos Aires 24: 5-165. Kohl, F. F. 1905. Hymenopterentypen aus der neotropischen Fauna. Verhandlungen Zoologische-Botanische Ceselschaft Wien 55: 338-366. Reed,E. C. 1894. EntomologiaChilena. Los fossores o avispas cavadoras. Anales de la Universidad, Republica de Chile 84: 599-653. Spinola, M. 1851 . In Gay, C. Historio Fisico y Politica de Chile. Maulde and Renon, Paris. Zoologia, vol. 6., 572 pp. J. HYM. RES. 1(1), 1992 pp. 165-174 Functional Morphology of the Abdomen and Phylogeny of Chrysidid Wasps (Hymenoptera: Chrysididae) Lynn Siri Kimsey Department of Entomology, University of California, Davis, California 95616, U.S.A. Abstract . — The wasp family Chrysididae is characterized in part by the loss of a functional sting, and the internalization of 2 or more abdominal segments. These segments are telescoped within the abdomen and function as an independently musculated ovipositor or genital tube. Accompanying this internalization are shifts in the position of the major muscles involved in pronation, retraction and protraction of the segments from that of the typical ground plan seen in other stinging wasps. There is also an accompanying loss of musculature on the remaining external segments. The degree of modification and internalization correlates with the type of host parasitized, with the least in Cleptinae (parasites of prepupal sawflies), and the most modification in Chrysidinae (nest parasites of bees and wasps). Phylogenetic relationships among chrysidid subfamilies can be traced using derived features of structural and muscular changes in the abdomen. In addition, these modifications reflect compromises between oviposition, copulation and defense. There are few studies of insects in which at- tempts are made to explore the function of structural features commonly used in systematics to demon- strate phylogenetic relationships. Within Hym- enoptera the structure and function of the oviposi- tor has been examined in some detail (Austin 1983, Austin and Browning 1981, Copland and King 1971, Oeser 1961, Robertson 1968, Scudder 1961). Unfortunately, in many insect groups neither the systematics nor the biology are sufficiently well understood to permit the examination of relation- ships between structural modifications and hosts, or other aspects of the biology. The family Chrysididae is one exception to this problem. The family has just been revised on a world basis, with detailed analysis of phylogenetic relationships (Kimsey and Bohart 1991), and at least general categories of hosts are known for tribes and sub- families. There appear to be strong correlations in this family between the type of host and modifica- tions of the chrysidid abdomen, in both sexes. These changes in external and internal morphol- ogy of the chrysidid abdomen support relation- ships discussed previously (Bohart and Kimsey 1982, Kimsey and Bohart 1991). In the vast majority of aculeate, or "stinging", wasps the ovipositor functions as both a defensive and an offensive structure, used to inject prey or potential predators with venom. This sting appara- tus has been secondarily lost or highly reduced in several groups, including the stingless bees (Meliponini, Apidae), a number of ant taxa, and Chrysididae. In all but the last group the apparent abdomen is otherwise relatively unmodified, with 6 external segments in females and 7 in males, excluding the propodeum, and the sting apparatus involves segments VIII and IX. The male genital capsule is internally subtended by gastral segment IX. The structure of the sting and male terminalia have been studied in detail by Carpenter (1986), Oeser(1961),Rasnitsyn(1980)andSnodgrass(1942) among others. However, within the family Chrysididae radi- cal changes in the abdomen of both males and females have occurred. In this group the sting is considerably reduced and functions more as an egg guide than in any defensive manner, and both the male and female genitalia are subtended by an eversible tube formed by 2 or more internalized abdominal segments. Somewhere in the transition from some ances- tral form to the Chrysididae the 2 apical external abdominal segments (VI and VII in females, and VII and VIII in males) were internalized, resulting in a primitive ground-plan of 5 external segments in males and 4 in females; a condition found in Cleptinae, Amiseginae and Loboscelidiinae. Al- though this ground-plan of 5 external abdominal segments is primitive for chrysidids, it is apomorphic within the Aculeata. This basic modi- fication of the abdomen in turn facilitated a series of specializations that are unique to this family, 166 Journal of Hymenoptera Research which reflect various compromises between ovi- position, copulation and defense. MATERIALS AND METHODS This study is based on morphological studies of the family Chrysididae. External morphology of more than 2000 species of Chrysididae was exam- ined for a monograph of the family (Kimsey and Bohart 1991). Internal anatomy was studied in dissections of preserved material representing several aculeate families, and subfamily groupings within the Chrysididae (Table 1). Table 1 . Taxa dissected for studies of abdominal musculature. The sex of specimens examined is given in parentheses, M = male, F = female. Family Subfamily Species Chrysididae Chrysidinae Chrysis nitidula (Fab.) M, F Chrysis sp. M Chrysurissa densa (Cr.) M, F Chrysura sp. (f) Hedychrum sp. M, F Cleptinae Cleptes alienus Patton M ClepHes semiauratus (L.) F Amiseginae Adelphc anisomorphae Kr. M, F Bethylidae Rhabdepyris sp. M, F Pompilidae Auplopus sp. M Apidae Apis mellifera L. F The muscle arrangements found in Rhabdepyris (Bethylidae), Auplopus (Pompilidae) and Apis (Apidae) all closely resembled one another (as in Fig. 1). Therefore, the condition found in these taxa was used as the primitive ground plan against which the muscle positions in chrysidids were compared (Figs. 2-4). These specimens were fixed in solutions using formalin-acetic acid (FAA). Unfortunately, I could only obtain specimens of Adelphe and Rhabdepyris preserved directly in 70% ethanol, without an in- terim fixative. The relatively poor state of preser- vation of these specimens made it impossible to determine muscle attachments in the ultimate and penultimate abdominal segments, those directly involved with the sting and genital capsule. Although the chrysidid abdomen is quite modified, homologies can be seen between the musculature in this family and that of other aculeates. There have been few published studies of the abdominal musculature of Aculeata (Duncan 1939, Snodgrass 1942). As a result, I am using the terminology for the musculature of Snodgrass (1 942) where possible, to aid in comparisons (Table Table 2. Terminology taken from Snodgrass (1942) and code numbers used in Figs. 1 -4 for muscles of the apparent abdomen, beginning at the petiole. Is — Median Intersegmental Ventral Muscle of Metathorax. This is the primary depressor of the abdomen, originating on the metasternum and attaching on sternum 11 (Snodgrass No. 118). 2s — Oblique Internal Ventral Muscle of Segment III. This muscle originates near the midline of segment III and attaches on the anterior apodeme of segment IV. It was found only in Chrysidinae. There is no clearly homologous muscle in the honeybee or other aculeates. It may be derived from 3s as that muscle has the same point of insertion. 3s — Lateral Internal Ventral Muscle. This muscle originates adjacent to the anterior sternal apodeme of the anterior sterum, and attaches on anterior apodeme of the posterior sternum (Snodgrass Nos. 131, 142, 153, 164, 175) 4s — Medial Internal Ventral Muscle. Originates on the apical margin of the anterior sternum, and attaches on anterior margin of the posterior sternum (Snodgrass Nos. 130, 141,152,163,174). 5s — External Ventral Muscle. This muscle originates basally on the anterior sternum and attaches on the apodeme of the posterior sternum (Snodgrass Nos. 135, 146, 157, 168). It — Medial Internal Dorsal Muscle. This muscle originates posterior to the anterior apodeme of the anterior tergum, and attaches apicomedially on the posterior tergum (Snodgrass Nos. 124, 133, 144, 155, 166). 2t — Lateral Internal Dorsal Muscle. This muscle originates posterior to the apodeme of the anterior tergum, and attaches laterally on the posterior tergum (Snodgrass Nos. 125,134,145,156,167). 3t — External Dorsal Muscle. This muscle originates posterolateral^ on the anterior tergum, and inserts on the anterior apodeme of the posterior tergum (Snodgrass Nos. 135,146, 157, 168). Its — Lateral Muscle of Tergum II. This muscle originates on the dorsal surface of the tergum, and attaches on the anterior margin of the sternum (Snodgrass No. 129). 2ts — First Lateral Muscle. This muscle originates posterolateral^ on the tergum, and extends apicolaterally between sternum and tergum, attaching below the anterior apodeme of the sternum (Snodgrass Nos. 138, 149, 160, 171). 3ts — Second Lateral Muscle. This muscle originates laterally on the sternum, and inserts laterally on the tergum (Snodgrass Nos. 13 9, 150, 161, 172). 2). Homologies were determined by the position of the muscle insertions, and the assumption that a shift in position was more likely than derivation of an entirely new muscle. The insertion was as- sumed to be the narrowest part of the muscle, often with a distinct tendon. This is not always easy to determine in Snodgrass' illustrations. Phylogenetic analysis of the resulting data set was done with the program Hennig-86 of Farris. Volume 1, Number 1, 1992 167 A terga B sterna 3ts 2ts 2ts 2ts Auplopus sp Fig. 1. Auplopus sp., male, terga (A), sterna (B). Letters refer to muscles given in Table 2. Roman numerals indicate segment numbers. Dashed lines indicate tergal, sternal and muscle margins covered by an adjacent plate. RESULTS Nonchrysidid Abdomen The abdominal musculature of the external ab- dominal segments appears to be fairly consistent when comparisons are made among distantly re- lated families. The typical configuration can be seen in Fig. 1 . The basic muscle pattern is repeated from one segment to the next, except in the first and last external segments. There are basically 3 sternal, 3 tergal and 3 tergosternal muscle pairs in each intermediate segment. The primary intersegmental muscles, 3s, 4s, It and 2t form a V-shaped con- figuration in the 3 nonchrysidid species examined (as in Fig. 1). Chrysidid Abdomen Although homologies can be seen between the musculature of the chrysidid abdomen and that of other aculeates, there are a considerable number of variations in muscle positions and development between the two as well as among the chrysidid subfamilies (Tables 2-3). The significance of one difference in the muscu- lature of segment II between the Chrysididae and other Aculeata examined is unclear. In other 168 Journal of Hymenoptera Research Table 3. A comparison of the presence or absence of specific muscles in 3 chrysidid subfamilies and the pompilid Auplopus. The muscle numbers correspond with those given in Table 2. Segment No. Auplopus Cleptinae Amiseginae Chrysidinae and Muscle II Its + + + + 2ts + 0 0 0 3ts 0 + + + It + + 0 0 3t + + + + 3s + + 0 0 4s + + 0 + 5s + + + + III 2ts + + + 0 3ts + + + + It + + + + 2t + + + 0 3t + + + + 2s 0 0 0 + 3s + + + + 4s + + + + 5s + + + + IV 2ts + + + 0 3ts + + + + It + + + + 2t + + + 0 3t + + + + 3s + + + + 4s + + + 0 5s + + + + V 2ts + + + 0 3ts + + + + It + + 0 + 2t + + + 0 3t + + + + 3s + + + + 4s + + + 0 5s + + + + VI 2ts + + + + 3ts + + + + It + + 0 + 2t + + + + 3t + + + + 3s + + 0 + 4s + + 0 0 5s + + + + aculeates sternum II has one tergosternal muscle pair inserting on the anterior apodeme. Thus it is labeled 2ts in Fig. 1 B. In chrysidids there is only one tergosternal muscle pair on segment II but since this is located laterally near the middle of the plate it is labeled 3ts. Superficially this appears to be a major difference between the two groups, but in fact may be a shift in th e position of 2ts in chrysidids. Cladistic analysis of the data set generated by muscle traits found in the chrysidid and nonchrysidid taxa, using the Hennig-86 program of Farris, resulted in a CI of 100 and RI of 100. MORPHOLOGY Cleptinae. — The external gastral segments are unspecialized; males have 5 segments and females 4. These external segments are freely articulated and well musculated. The remaining abdominal segments form an ovipositor or genital tube from segments VI-VIII (females) or VII-IX (males), which is held telescoped within the abdomen. The internal segments VI or VII-IX are not par- ticularly differentiated from the external ones. They differ primarily in the absence of the distinctive lateral tergal lobe seen on the external segments. Terga II-V or VI have a large lateral lobe, the laterotergite, set off from the rest of the tergum by a faint weakening apically and by the position of the spiracle. This lobe covers a large part of the sternum. Cleptines have largely retained the V-shaped configuration of It and 2t, and 3s and 4s, typical of other aculeates (Fig. 2). These 4 muscle pairs are also well developed. However, It and 2t have anteriorly shifted away from the anterior apodeme and have assumed a more medial position. Amiseginae. — As in cleptines the external ab- domen consists of 5 segments in males and 4 in females. However, in this group the intersegmental musculature and configuration of the terga has been considerably modified (Fig. 3). The invagi- nated segments VI or VII-VIII are greatly reduced, with VIII represented by linear, almost membra- nous flaps. In addition, terga II and III cannot be moved independently and appear to be closely articulated or fused. No indication of the presence of It or 2t could be found between these two segments. There are also other differences on segments III— VI. Muscles It and 4s are very slender, and are located nearly parallel with the midline of the plate. 2t and 3s are short and originate away from the anterior apodeme, often toward the midline of the segment. Unlike the Cleptinae, terga II-IV or V have the laterotergite clearly delimited by a sulcus extend- ing from the anterior to the posterior tergal margin. The spiracle is located just ventrad of this sulcus. This tergal sulcus forms a midline extending the length of the abdomen when it is viewed in profile. Volume 1, Number 1, 1992 169 A terga Cleptes alienus Fig. 2. Cleptes alienus, male, terga (A), sterna (B). Letters refer to muscles given in Table 2. Roman numerals indicate segment numbers. Dashed lines indicate tergal, sternal and muscle margins covered by an adjacent plate. The terga and sterna are both convex in this sub- family. The reduced internal segments result in a differ- ent configuration of the ovipositor and genital tube as compared with other chrysidids. In females, segments VI-VIII form a sheath around the elon- gate sting elements, rather than a separate eversible tube basad of the sting elements. Segments VII-IX are also reduced in males, and form a short, simple pregenital element at the base of the genital cap- sule. Based on dissections of dried specimens of Loboscelidia (Loboscelidiinae), and the descriptions of Day (1978), the structure of the abdominal terga and sterna are nearly identical to those in Amiseginae. The abdominal musculature in loboscelidiines probably closely resembles that of amisegines. Chrysidinae. — The number of external gastral segments is reduced to 4 or fewer in males and 3 or fewer in females, depending on the tribe. Parnopines are the least reduced with 4 in males and 3 in females (Telford 1964). Elampines and chrysidines have 3 in both sexes, and allocoeliines have 2 in both sexes, with the sternum of segment IV still largely exposed. The musculature is considerably modified on these external segments (Fig. 4). As in Amiseginae the tergum is sharply divided into a primary tergite and secondary laterotergite by a sulcus. The spi- racle may be located near the sulcus on the primary tergite or on the laterotergite. The sterna are nar- rowed and the laterotergite sharply bent ventrad, forming part of the apparent sternum. The juncture between the primary tergite and laterotergite is 170 Journal of Hymenoptera Research A terga B sterna VII \ y? VIII \^^ Adelphe anisomorphae VIII Fig. 3. Adelphe anisomorphae, male, terga (A), sterna (B). Letters refer to muscles given in Table 2. Roman numerals indicate segment numbers. Dashed lines indicate tergal, sternal and muscle margins covered by an adjacent plate. sharply folded. The resulting sternum is flat or concave, giving the gaster a cuplike appearance. The internalized segments are highly modified in chrysidines. However, they have all retained the basic musculature found on these segments in other aculeates. In addition, chrysidines can roll up in a tight ball when disturbed. Several structural changes allow this posture. The region around the petiolar articu- lation between the propodeum and first gastral segment has become modified, allowing the ab- domen to be rotated up against the thoracic venter. The petiolar socket is broader in chrysidines, the hindcoxal articulations are oriented in a more horizontal position than in cleptines, and the upper surface of the hindcoxae is flattened, allowing the abdomen to rotate anteroventrally and cover the legs and thoracic venter. When the abdomen is curled up against the head and thorax only the top of the eyes, the upper one-third of the thorax and the femorotibial articulations of the legs are visible (Fig. 5b). The arrangement of muscles in the Chrysidinae differs considerably from that of other chrysidids as well as other aculeates, although it more closely resembles the pattern seen in Amiseginae than any other taxa (Table 3). There are 2 sternal muscles (Fig. 4B) on segments III and IV, which differ in position from that seen in the other taxa examined. These are labeled 4s and 2s respectively. Muscle 4s has a similar attachment and insertion as 4s in other chrysidids. Muscle 2s does not appear to be ho- mologous with any muscle seen in the aculeate ground plan, although the insertion of this muscle on the anterolateral apodeme suggests that it may be derived from 3s. However, contraction of both of these muscles would not only pull the sternal plate anteriorly but would also bend the plates involved, increasing the convexity of the abdomi- nal sternum. There are other differences in musculature as well. Segments III-V lack 2t and 2ts, and segments IV-VI lack 4s. Finally, segment III lacks 2s. Segment IV is the most highly modified in Chrysidini where the origin of 3t, the primary protractor of the internal segments, is marked by Volume 1, Number 1, 1992 171 B sterna A terga 3ts vm-yf^,315 Chrysis sp. Fig. 4. Chrysis sp., male, terga (A), sterna (B). Letters refer to muscles given in Table 2. Roman numerals indicate segment numbers. Dashed lines indicate tergal, sternal and muscle margins covered by an adjacent plate. the anterior margin of the pit row (Fig. 4A), a row of ovoid depressions near the apical margin of the tergum. Segments V-VIII are differently shaped than the external segments, having strong anterolateral lobes on both the terga and sterna. DISCUSSION The internalization of abdominal segments al- lowed the chrysidids to develop a highly mobile and independently musculated ovipositor or geni- tal tube. Several concurrent modifications are in- volved. The internalized segments retained their intersegmental musculature, with the associated 172 Journal of Hymenoptera Research Fig. 5. Defensive posture of Cleptes alienus (A) and Hedychrum sp. (B). enlargement of the tergal, sternal and tergosternal muscles, particularly 3t, 4s, 5s and 3ts. The intersegmental muscles, 3t, 5s and 4s, between the apical external segment and basal internal segment, serve as basal protractors and retractors of the tube. These are shifted in position and enlarged as shown in Fig. 4, where the origin of the major tergal protractor muscle, 3t, on tergum IV is situated submedially near the posterior margin of the ter- gum, and the muscle itself is elongate anteriorly. Cont raction of this muscle pulls the anterior margin of tergum V nearly even with the posterior margin of IV. Relaxation of this muscle and contraction of It pulls the anterior apodemes of tergum V anteri- orly, and nearly even with the anterior margin of IV. Muscle 5s on the sternum functions similarly. Therefore, excertion of the abdominal tube is pri- marily accomplished by contraction of 3t and 5s . The tube is telescoped within the abdomen at rest by contraction of 3s, 4s, It and 2t. In addition, retention of the intersegmental muscles on the tube segments enabled it to be flexible and mobile. The external segments have retained remnants of intersegmental muscles but these muscles are con- siderably reduced or lost in the case of those that function as tergal retractors ( 1 1) and pronators (5s), or greatly enlarged as in the muscle that holds the anterior tergal apodeme of a posterior segment to the side of the anterior tergum (3t), resulting in an almost complete loss of flexibility in the external segments in the Chrysidinae. Muscle 3t has a dual function in the Amiseginae and Chrysidinae. On the external segments 3t is very short and actually serves to limit movement between these segments. This muscle serves as one of the primary protrac- tors of the internal segments and between these and the apical external segment. Retracting the apical abdominal segments within the abdomen necessitated a change in the position of the muscle attachments between the apical external and basal internal segments. In chrysidids this muscle attachment has shifted from the base of the apical external segment to a submedial placement. Retraction is accomplished by contraction of 3s, 4s, 1 1 and 2t. In other aculeates these muscles (3s, 4s, It and 2t) serve to hold the abdominal segments tightly together and enable lateral, dorsal or ventral pronation, or allow lim- ited posterior extension or elongation (3t and 5s). The degree of modification of the intersegmental musculature varies from subfamily to subfamily, with the least occurring in the Cleptinae, and the greatest in Chrysidinae. The result is that in the Chrysidinae, where the largest number of seg- Volume 1, Number 1, 1992 173 =1=5= =17= ===j [j=8=10=18 ==7=9=13=15===2=3=4=6=11=12=14=19= Pompilidae Cleptinae Amiseginae =19= Chrysidinae Fig. 6. Phylogenetic tree showing relationships of chrysidid subfamilies, using features of the abdomen and hosts. Numbers refer to derived characters given below. 1, Abdominal segments VI- VIII (females) or VII-IX (males) internalized. 2, Abdominal segments V (females) or VI (males) also internalized. 3, Segment III with muscle 2s. 4. Segments III-V without 2t. 5. Segment II without 2ts. 6. Segments III-V without 2ts. 7, Segment II without 1 1. 8, Segments V-VI without 1 1. 9, Segments II and VI without 3s. 10, Segment II without 4s. 11. Segments IV-VI without 4s. 12, Segment III with 2s. 13, Muscles It and 2t, and 3s and 4s not forming V-shaped configuration. 14, Abdominal venter flat or concave. 15, Terga with laterotergite separated by complete sulcus. 16, Segments VIII and IX extremely reduced, linear. 17, Parasites of sawfly prepupae. 18, Parasites of wasps and bees. ments are invaginated , the external abdomen is almost completely inflexible. In Cleptinae the internal segments are not strongly differentiated from the external segments. The resulting ovipositor tube is robust and long, and the external abdomen retains some flexibility. These wasps parasitize prepupal sawfly larvae, ovipositing through a hole opened in the host cocoon, which is often located in soil or leaf litter. In Amiseginae and Loboscelidiinae the intersegmental muscles are reduced on the exter- nal segments. The internal segments are also re- duced, resulting in a needlelike ovipositor or short pregenital ring. These wasps parasitize walking stick eggs that are singly broadcast, and have a thick chorion. They initially open the egg by nip- ping a small hole in the chorion, using the oviposi- tor to place an egg in the phasmatid egg (Costa Lima 1936, Krombein 1983). The greatest degree of modification has oc- curred in the Chrysidinae. These wasps are pri- marily nest parasites of wasps and bees, and will enter a nest whether the adult host is present or not. As a result, a third component, protection from attacks by the host, is involved in the abdominal modification of this group. Therefore, in this sub- family these modifications represent compromises between oviposition, copulation and defense. The chrysidid wasp rolls up in a ball and the inflexible cuplike external abdomen is used as a protective shield covering the appendages. The internalized, intermusculated segments provide the flexibility needed for oviposition and copulation, while be- ing retractable and therefore not vulnerable to damage by the adult host. Some use has been made of the shape of the sternal plates in phylogenetic discussions of the relationships of the families placed in the Chrysidoidea. Rasnitsyn (1980, 1988) used the shape of sternum II and how it joined III as one of several characters to demonstrate the close relationship among Chrysididae, Bethylidae and Embolemidae. However, his assumptions about the morphology of sternum II appear to be misinterpretations of the structure of this plate. Based on the position of muscles on sternum II this plate is not secondarily expanded into "paired membranous lobules over- lapping the base of III". There is no indication internally of a butt-joined articulation between sternum II and III. The butt-joined articulation between these sterna is more clearly an apomorphy for Bethylidae. The validity of this character was first called into question by Carpenter (1986). These changes in abdominal morphology can be used to demonstrate the phylogenetic relation- ships among the chrysidid subfamilies (Fig . 6). In fact there is no homoplasy in these musculature traits. When this data is analyzed the resulting cladogram is identical to those produced using strictly external morphological characteristics (Bohart and Kimsey 1982, Kimsey and Bohartl991). ACKNOWLEDGMENTS This study was made possible by the assistance of several individuals who provided some of the preserved material used in this study , including G. Gibson, D. S. Horning and L. Masner, and support from NSF, grants Nos. BSR 8600341 and RII-86-20062. Thanks also to Richard M. Bohart and Jim Carpenter for comments on the manuscript. 174 Journal of Hymenoptera Research LITERATURE CITED Austin, A. D. 1983. Morphology and mechanics of the ovipositor system of Ceratobaeus Ashmead. International Journal of Insect Morphology and Embryology 12: 139-155. Austin, A. D. and T. O. Browning. 1981. A mechanism for movement of eggs along insect ovipositors. International Journal of Insect Morphology and Embryology 10: 93-108. Bohart, R. M. and L. S. Kimsey. 1982. A synopsis of the Chrysididae in America north of Mexico. Memoirs of the American Entomological Institute (33): 1-266. Carpenter, J. M. 1986. Cladistics of the Chrysidoidea. Journal of the New York Entomological Society 94: 303-330. Copland, M. J. W. and P. E. King. 1971. The structure and possible function of the reproductive system in the Chalcididae. Entomologists Monthly Magazine 107: 230-239. Costa Lima, A. da. 1936. Sur un nouveau chryside: Duckeia cyanea, parasite des oeufs de phasmide, pp. 173-175. In Jivre Jubilaire E. L. Bouvier. Paris, Firmin-Didot et Cie. Day, M. C. 1978. The affinities of Loboscelidia Westwood. Systematic Entomology 4: 21-30. Duncan, C. D. 1939. A contribution to the biology of North American vespine wasps. Stanford University Publications in Biological Science 8: 1-272. Kimsey, L. S. and R. M. Bohart. 1991 (1990). Chrysidid wasps of the world. Oxford University Press, Oxford, x + 652 pp. Krombein, K. V. 1983. Biosystematic studies of Ceylonese wasps, XI: A monograph of the Amiseginae and Loboscelidiinae. Smithsonian Contributions in Zoology (376)- 1-79. Oeser, R. 1961. Vergleichend-morphologische Unter- suchungen iiber den Ovipositor der Hymenoptera. Mitteilungen aus dem Zoologischen Museum in Berlin 37: 1- 119. Rasnitsyn, A. P. 1980. The origin and evolution of Hymenoptera. Trudy Paleontological Institute 174: 1-190. [In Russian] Rasnitsyn, A. P. 1988. An outline of evolution of hymenopterous insects. Oriental Insects 22:115-145. Robertson, P. L. 1968. A morphological and functional study of the venom apparatus in representatives of some major groups of Hymenoptera. Australian Journal of Zoology 16:133-166. Scudder, G. G. E. 1961. The functional morphology and interpretation of the insect ovipositor. Canadian Entomologist 93: 267-272. Snod grass, R. E. 1942. The skeletomuscular mechanisms of the honeybee. Smithsonian Miscellaneous Collections 103: 1-120. Telford, A. D. 1964. The nearctic Pamopes with an analysis of the male genitalia in the genus. University of California Publications in Entomology 36:1-42. J. HYM. RES. 1(1), 1992 pp. 175-234 Mole Cricket Hunters of the Genus Larra in the New World (Hymenoptera: Sphecidae, Larrinae) Arnold S. Menke Systematic Entomology Laboratory, PSI, Agricultural Research Service, USDA, c/o National Museum of Natural History NHB 168, Washington D.C. 20560, U.S.A. Abstract. — Species of Larra in the New World are described, illustrated, their distributions summarized on maps, and a key for their identification provided. The known biologies are summarized and past efforts to introduce exotic species to the U.S. and Puerto Rico to control mole crickets are described. Eight species are recognized including one new one, stangei, from Bolivia and Argentina, and they are divided among three species groups. The females of two species, bicolor Fabricius and praedatrix Strand are inseparable. The following new synonymy is proposed: Larrada gastrica Taschenberg, 1870, Larra guiana Cameron, 1912, and Larra scapteriscica Williams, 1928 = Larra bicolor Fabricius 1804; Larra paraguayana Strand, 1910, Notogonia gastrifera Strand, 1910, and Larra pacifica Williams, 1928 = Larra praedatrix (Strand), 1910; Larra braunsii Kohl, 1898, Larra transandina Williams, 1928 = Larra godmani Cameron, 1889 (godmani is the first available name for the preoccupied species Larrada aethiops Smith, 1873). Species groups are used to arrange the species on a world basis, and the Old World subgenus Cratolarra Cameron is reduced to a synonym of Larra. Some characters that are important from a phylogenetic standpoint are analyzed for Larra and the other genera in the subtribe Larrina. A cladogram showing relationships of these taxa is provided. Larra is demonstrated to be derived from ground nesting ancestors. The genus Larra has become important in recent years because of the need to find natural enemies of three neotropical mole crickets introduced to the southeastern United States. Mole crickets cause millions of dollars of damage yearly to turf and crops, and they cannot be controlled economically with chemicals. Thus, natural enemies offer the best hope for control. Wasps of the genus Larra are exclusive predators of mole crickets, but the New World species have not been identifiable with any degree of certainty due to the lack of a modern revision. Furthermore, choosing the right species of Larra for liberation in the U.S. depends on knowledge of their distribution in the Neotropical Region and their host preferences. This revision has resolved identification of the species (although there are still problems that need further study) and mapped their geographic ranges. Determination of host preferences is beyond the scope of my study, but now that the species of Larra are identifiable, other scientists can examine predator/host relationships more accurately. When this study was initiated the New World fauna was represented by 16 species of Larra (Bohart and Menke, 1976), all but one of which were Neotropical. After examining the types of most of these, as well as descriptions of a few taxa whose types are missing, one species, parvula Schrottky (1903), has been transferred to the genus Lin's (New Combination), and two others listed by Bohart and Menke in the genus Liris, gastrifera Strand (1910) and praedatrix Strand (1910), have been transferred to Larra (New Combination). Considerable new synonymy has resulted in reducing the number of New World species of Larra to eight, one of which is new to science. These species have been segregated into three species groups. Problems of species discrimination remain. For example, the two most abundant species in the New World, bicolor Fabricius and praedatrix (Strand), are separable only in the male sex, and the latter species has considerable genitalic variation. This variation may mean that there are more species than I have recognized, but resolution of this will probably require rearing experiments, or more sophisticated techniques such as cuticular hydrocarbon analysis, not to mention more intensive collecting. In summary, Larra is a frustratingly difficult genus, and it is sure to tax the ability of the next person who studies it. INSTITUTIONS LENDING MATERIAL I have examined over 4200 specimens during this study. They were borrowed from the following collections. Parentheses enclose the name of the contact person and capitalized symbols used to identify sources of material cited in the text. 176 Journal of Hymenoptera Research Academy of Natural Sciences, Philadelphia, Pennsylvania (Donald AzumaXANSP) American Entomological Institute,Gainesville, Florida (David Wahl) American Museum of Natural History, New York (Eric Quinter) Anthony Raw collection, Universidade de Brasilia, Brasilia D.F., Brasil Bee Biology Laboratory, USDA, Utah State University, Logan, Utah (Terry L. Griswold) Bishop Museum, Honolulu, Hawaii (Scott Miller) (BISHOP) California Academy of Sciences, San Francisco, California (W. J. Pulawski) California Insect Survey, University of California, Berkeley, California (Michael Prentice) California State Collection of Arthropods, Sacramento, California (Marius WasbauerXCSDA) Canadian National Collection, Ottawa, Canada (John Huber) Carnegie Museum, Pittsburgh, Pennsylvania (Chen Young) Centro de In vestigacion y Mejoramiento de la Cana de Azucar, Santa Cruz, Bolivia. (Cristobal Pruett) Department of Entomology, Cornell University, Ithaca, New York (E. R. HoebekeXCORNELL) Florida State Collection of Arthropods, Gainesville, Florida (F. D. Bennett, Lionel Stange) (FSDA) Henry Hespenheide Collection, University of California, Los Angeles, California Hope Entomological Collections, University of Oxford, Ox- ford, United Kingdom (C O'Toole) (OXFORD) Illinois Natural History Survey, Champaign, Illinois ( Kathleen Methven) Institute Miguel Lillo, Tucuman, Argentina (A. Willink) Istituto di Entomologia Agraria e Apicoltura, Torino, Italy (Guido Pagliano) Manfredo Fritz Collection, Salta, Argentina (FRITZ) Martin Cooper Collection, Lyme Regis, Dorset, United Kingdom Martin-Luther-Universitat, Halle, Germany (HALLE) Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina (Jorge Genise). Museo de Invertebrados G. B. Fairchild, Universidad de Panama, Panama (Diomedes Quintero A.) Museu de Zoologia, Universidade de Sao Paulo, Brasil (Carlos Brandao) Museum d'Histoire Naturelle, Geneve, Switzerland (Claude Besuchet) (GENEVA) Museum fur Naturkunde der Humboldt-Universitat zu Berlin, Germany (Frank Koch) (BERLIN) Museum National d'Histoire Naturelle, Paris, France (Janine Weulersse) (PARIS) Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts (James Carpenter) Museum of Zoology, University of Michigan, Ann Arbor, Michigan (Mark O'Brien) Nationaal Natuurhistorisch Museum, Leiden, The Netherlands (Kees van Achterberg) (LEIDEN) National Museum of Natural History, Washington DG. (A. S. Menke) (USNM) Natural History Museum of Los Angeles County, Los Angeles, California (Roy Snelling) Naturhistorisches Museum, Vienna, Austria (Max Fischer) (VIENNA) Oregon State University, Corvallis, Oregon (George Ferguson) Provincial Museum of Alberta, Alberta, Canada (Albert FinnamoreHALBERTA) Richard M. Bohart Entomological Museum, University of California, Davis, California (Lynn Kimsey) Snow Entomological Museum, University of Kansas, Lawrence, Kansas (Robert W. Brooks) The Natural History Museum, London, United Kingdom (Colin Vardy) (BMNH) Universidad Central de Venezuela, Maracay, Venezuela (Jose Luis Garcia R.) (MARACAY) Universidad deCosta Rica, San Jose, Costa Rica (Paul Hanson) Zoological Museum, Moscow, Russia (Alexander V. Antropov) Zoologisk Museum, Copenhagen, Denmark (Ole Lomholdt) (COPENHAGEN) BIOLOGY Bohart and Menke (1976) summarized the literature on harm. Since then, a number of papers have been published on Larra bicolor by workers associated with the introduced mole cricket problem in Florida, principally James L. Castner. Much of this subsequent literature was summarized by Castner (1988), and the account that follows, unless stated otherwise, is taken from that paper. Larra bicolor Fabricius Foraging. — Floral visitation occurs from about 8:30AM to 3:30PM with males predominating in the morning. In Puerto Rico L. bicolor most commonly visits flowers of Spermacoce verticiUata L. (Rubiaceae), but Croton glandulosus L. and Euphorbia heterophylla L. (Euphorbiaceae), both of which have extrafloral nectaries, are also favorites. In Bolivia L. bicolor visits Cissus sp. (Vitaceae) almost exclusively if it is flowering, but Spermacoce verticiUata, Euphorbia sp., and occasionally Mikania micrantha (Compositae) are attractive to the wasp (Bennett and Pruett, 1991). Mating. — Chemoreception of a female pheromone is apparently used by the male to locate the opposite sex when several meters away, but once near the potential mate, vision is used to home in on her. Females are approached from behind, the male attempting to mate by either running up on her, or flying directly on to her. Castner (1988) stated that females foraging on flowers are never approached, and that only females on the ground were mated, but Bennett and Pruett (1991) commonly observed males searching for females in foliage. Actual mating has rarely been observed. According to Bennett and Pruett (1991 ), once a male has landed on a female, she raises her abdomen if Volume 1, Number 1, 1992 177 she is receptive, and the male engages her for less than five seconds (" . . it is almost a non-event"). Afterwards both individuals groom the tip of the abdomen with their hindtarsi. Prey searching. — This activity occurs from about an hour after sunrise to 3:45 PM. Prey searching occurs on cloudy, overcast days as well as sunny ones, but not apparently on rainy days. Typically the female walks over the ground until a mole cricket surface gallery is encountered, whereupon she excavates down into it and enters the tunnel. Just what happens between wasp and mole cricket in the burrow is unknown, but the orthopteran typically evades the wasp by surfacing. According to Castner, surfacing mole crickets escape capture by the wasp about 50% of the time. Wasps return to the surface often apparently to determine if the host has surfaced. Small nymphs are attacked as well as large adults. Paralysis of prey. — The female captures the surfaced mole cricket. She then stings the host repeatedly in a fixed pattern: to the base of the fore and midlegs, and to the base of the palpi. Paralysis generally lasts for 3 to 4 minutes. If the cricket revives before oviposition is complete, more stings are administered. Once the mole cricket is paralyzed, the wasp often turns it on its back and chews at the base of one of the forelegs, appearing to feed on exuding body fluid. Oviposition. — Prior to oviposition the wasp usually rubs the tip of her abdomen over the ventral area of the mole cricket, possibly to determine if a wasp egg or larva is already present. If an egg is detected, the wasp initiates a searching/biting behavior that may take several minutes before the egg is removed (Castner, 1986). In experiments females would even remove their own eggs from mole crickets. The egg is attached in the soft, membranous tissue between the first and second pair of legs of the host, lateral to the midventral line. After deposition of the egg, the wasp then either flies away or remains with the host until it revives and re-enters the ground. Some wasps have been observed to chase away foraging ants. Larval development. — Under laboratory conditions eggs hatch in 6-7 days. The first instar larva feeds on hemolymph at the site of egg attachment and after 8-9 days has progressed through four instars, growing slowly all the while. One to three days later the fifth and final instar has killed the host, consumed the soft, inner tissues and grown suddenly to a length of 14-26 mm. In about a day the mature larva spins a cocoon in the mole cricket's gallery. An adult wasp emerges 6-8 weeks later. Host suitability. — Larra bicolor is not necessarily host specific, at least under laboratory conditions in Florida, where the wasp was able to develop on five neotropical species of Scapteriscus mole crickets (abbreviatus Scudder, borellii Giglio-Tos (acletus Rehn and Hebard is a synonym, see Nickle 1992), vicinus Scudder, didactylus (Latreille), and imitatus Nickle and Castner), the first three of which are established in the state. However, survival on S. didactylus, an exotic species so far not known in the U.S., was significantly less than in the other four, suggesting possession of some type of anti-parasite mechanism by the host. Similar results were obtained in laboratory tests in Bolivia with four species of Scapteriscus (Pruett and Bennett, 1991), but bicolor preferred S. vicinus Scudder. In laboratory studies, L. bicolor reluctantly accepted the native Floridian mole cricket Neocurtilla hexadactyla (Perty), whose range also includes much of South America (Castner, 1988, Pruett and Bennett, 1991). But this mole cricket has a defense mechanism: it secretes a viscous anal fluid that entangles the attacking wasp, thus permitting the prospective host to escape. In Bolivian laboratory trials, Pruett and Bennett demonstrated that of 328 bicolor eggs successfully laid on N. hexadactyla, only 5 developed to the pupal stage, and many died in the first instar. Apparently this mole cricket has more than one mechanism for dealing with its attackers. Larra anatis Fabricius Smith (1935) extensively studied the only native North American Larra, and his account shows that analis has basically the same behavior as bicolor. This wasp attacks Neocurtilla hexadactyla, the native North American mole cricket. Smith observed that wasps sometimes were entangled by the same sticky substance that this mole cricket used to thwart attacks by bicolor. The only difference in the behavior of analis is that the egg is attached behind the hindleg. Development from egg to cocoon ranged from 12 days in mid summer to about 30 days in the fall. Egg placement behind the hindleg was noted by Williams (1928, p. 42) in an unidentified species from Tena, Ecuador. The only species from Tena represented by females in Williams' material (BISHOP & USNM) are godmani (Cameron) and altamazonica Williams, both of which belong in the analis species group. Egg placement behind the 178 Journal of Hymenoptera Research hindleg of the host may thus be a feature of the analis group. Larra godmani Cameron Two females that I have studied, one from Chapare, Bolivia, and one from Cauqueta, Colombia, have prey pinned beneath them. Both are irrimatures of a species of NeocHrh7/fl(det.D. Nickle). Bennett et al. (1990) state that in Bolivia this Larra (as braunsii) attacks medium to large nymphs of Scapteriscus vicinus and small nymphs of S. borellii (as acletus). INTRODUCTIONS TO CONTROL MOLE CRICKETS Hawaii.— Introductions of exotic mole crickets to Hawaii, Puerto Rico, and the southeastern US prompted a search for control agents. F. X. Williams pioneered the research on Larra as a control agent. He explored the Philippines and Australia in an effort to find natural predators for Gryllotalpa africana (Palisot de Beauvois), established on the islands of Oahu and Kauai. In 1921 and 1925 he sent live material of Larra luzonensis Rohwer collected in the Philippines to Hawaii, and it was liberated at various sites on Oahu where it became established (Williams, 1928). He also liberated another Philippine species, L. amplipennis (Smith) (as L. sanguinea), in 1922 but it failed to become established. Williams then turned to South America in his search for an effective species of Larra. He sent material of Larra bicolor (as americana and scapteriscica) taken in Belem, Brasil, to Hawaii in 1924, but the introduction failed. Puerto Rico.— George Wolcott (1941) sought predators of mole crickets at Belem, Brasil, where F. X. Williams (1928) found Larra to be common. Between 1936 and 1940 Wolcott and his associates liberated a number of collections of L. bicolor in Puerto Rico, and the species became established there. Of particular interest was the discovery that survival of live wasps in transport was greatly enhanced when live but paralyzed mole crickets accompanied them. This technique resulted in the accidental introduction to Puerto Rico of another species of mole cricket, however (Nickle & Castner, 1984). Florida.— Three exotic species of mole crickets of the genus Scapteriscus were introduced into the southeastern U.S. around the turn of century (abbreviatus, borellii, and vicinus). Now well established, they cause considerable damage to turf and pasture grasses, especially vicinus. It is estimated that in Florida alone these herbivores cost in excess of $44 million annually when damage and control measures are tallied (Hudson, et al., 1988). In the late 1970's scientists at the University of Florida began investigating potential predators and parasites, and by 1981 had released Larra bicolor from Puerto Rico at three sites in Florida: Gainesville, Tampa, and Fort Lauderdale (Hudson, et al., 1988). Subsequent releases were made at Bradenton and Lakeland in 1982-83. The wasp became established only at Fort Lauderdale, presumably either because the other sites were too cold for winter survival of an essentially tropical wasp, or because too few wasps were released or they were too old. Currently searches for suitable La rra for introduction to northern Florida have been centered in Bolivia. Bolivian material of L. bicolor and L. godmani(as braunsii) was liberated at several sites in Alachua Co. in 1988-89 (Bennett et al., 1990). The success of these releases has not been evaluated. Among material of L. bicolor assembled for this revision is a single female collected at Watson's Hammock, Big Pine Key in Monroe Co., Florida, in 1986 (ALBERTA). This site is far from Fort Lauderdale, and it may represent a hitherto undetected natural population of L. bicolor, or a chance introduction. As pointed out in the systematic treatment of this species, it is possible that this Big Pine Key female is actually the species L. praedatrix. RECOMMENDATIONS FOR INTRODUCING LARRA TO FLORIDA The three introduced mole crickets in the southeastern U.S. originated in southern South America, primarily the region around Buenos Aires, Argentina (Nickle and Castner, 1 984). Thus it would seem most rewarding to collect Larra from that region for introduction to the U.S. Also, the climate there is temporate, rather than tropical, and the wasps would have a better chance of surviving in North America, especially if collected south of the 30th Parallel. Four species of Larra occur commonly in the area around Buenos Aires: burmeisterii, bicolor, praedatrix, and princeps (the last three belong in the bicolor group). Any of these species may be good candidates for introduction to Florida, and in fact, L. bicolor from Puerto Rico has been successfully Volume 1, Number 1, 1992 179 introduced there. It survived only in southern Florida, however, and introductions of L. bicolor from a more temperate region such as northern Argentina would seem more logical. Prey specificity for species of Larra is poorly understood at present, and the mole crickets attacked by burmeisterii, praedatrix, and princeps are unknown, Larra princeps in particular would seem worthy of study, because it has the southernmost range in South America of any species in the genus (nearly to the 40th Parallel) and thus may be expected to survive in the cooler parts of the southeastern U.S. Genus LARRA Fabricius Larra Fabricius, 1793:220. Type species: Larra ichneumoniformis Fabricius,1793 (= Sphex anathema Rossi, 1790), designated by Latreille, 1810. Larrana Rafinesque-Schmaltz, 1815:124. Emendation of Larra Fabricius. Lara Drapiez, 1 81 9:54. Lapsus or emendation of Larra Fabricius. Monomatium Shuckard, 1840:181 (no species). Type species: Larraxena princeps F.Smith, 1851, designated bv Pate, 1935 (first included species). Lyrops Dahlbom, 1843:132. Type species: Tachytes paganus Dahlbom, 1843, monotypic. Not Lyrops Illiger, 1807. Larraxena F.Smith, 1851:30. Type species: Larraxena princeps F. Smith, 1851, monotypic. Larrada F. Smith, 1856:273. Type species: Larrada anathema (Rossi), 1790, original designation. Cratolarra Cameron, 1900:34. Type species: Cratolarra femorata Cameron, 1900, monotypic. NEW SYNONYM. The extensive generic description in Bohart and Menke (1976) is generally quite thorough, but one structure was insufficiently described, and two others not mentioned. The female scape was described as conspicuously shining in contrast to the flagellum in many species, and while that is true, it is important to add that it is also largely asetose and impunctate in those species (Fig. 8). The pronotum in Larra usually has a transversely elongate sulciform depression anteromedially, although in some species there are two oval pits in the same position that may be narrowly joined. Finally, in many species of Larra, the inner surface of the forebasitarsus has an asetose linear polished zone (Fig. 28). It occurs in both sexes but is best developed in the female. In a few species the basitarsus is setose throughout (Fig. 26) as in Liris, or has a small, rather poorly defined asetose area (Fig. 27). The difficulty in separating Larra from the genus Lin's was well documented by Bohart and Menke (1976:235, 240). The polished, asetose zone present on the inner surface of the forebasitarsus of many species of Larra is an additional difference from Liris, but unfortunately it is not universal. The apparent differences in the biology of these taxa argue for maintaining Larra as a separate genus, but the problem of finding clear morphological differences remains. Subgenera and species groups. — Bohart and Menke (1976) recognized two subgenera that were differentiated by the presence (Larra) or absence (Cratolarra) of spine rows on the foretibia. After examining 25 of the 60 species in the genus I have reached the conclusion that Cratolarra is only one of several recognizable groups within Larra, and certainly no more distinct than the others. My phylogenetic analysis confirms this and therefore I am synonymizing Cratolarra (NEW SYNONYM). I am using species groups to segregate the taxa of Larra. The Old World Cratolarra becomes the maura group, its name based on the oldest species in the group. Tsuneki (1967) called it the carbonaria group. Other Old World groups recognized by me include the amplipennis and anathema groups. The New World species are divided among the bicolor, burmeisterii, and analis groups. They are characterized later in the paper. The amplipennis group includes species with a setose forebasitarsus, a setose female pedicel, a largely asetose polished frons in the female (an apomorphy), a flat non-beveled labrum, spine rows on the female foretibia (an apomorphy), and placoids on most flagellomeres of the male. In addition the female lacks an ocular sinus. Species examined from this group include amplipennis (Smith) and betsilea Saussure. The anat liana group shares most of the characters of the amplipennis group. But the female pedicel is largely asetose and polished dorsally, and the forebasitarsus has a poorly defined asetose zone on its inner surface; both are apomorphies. I have examined anathema (Rossi) and melanocnemis Turner. The last species is only provisionally assigned to the group. The maura group lacks spine rows on the female foretibia, a character that sets it apart from all other species of Larra. I regard this state as plesiomorphic in Larra but my phylogenetic analysis suggests that in the maura group the absence of spines is a reversal (see Cladogram). The female pedicel is completely asetose and polished, the female frons is asetose and polished, the female upper interocular distance is less than half the lower interocular distance, and 180 Journal of Hymenoptera Research the female vertex has a deep sinus around the inner eye margin - all apomorphies. In addition, the labrum is flat, not beveled apically, and the male has placoids on most flagellomeres; both are plesiomorphic features. Species of this group that I have examined are: carbonaria (Smith), femorata (Saussure),fenchihuensisrYsune\d,heydeniiSanss\xre, luzonensis Rohwer, tnaura (Fabricius), outeniqua Arnold, polita (Smith), saussurei Kohl, and variipes Saussure. Species characters. — New World Larra have exasperatingly few characters. Some of those used by Williams (1928) such as thoracic punctation, presence or absence of a median carina on the propodeal dorsum, body and wing color, and details of the female vertex are unreliable. Other features used by Williams are really group characters: female pedicel asetose, polished, and female vertex with ocular sinus. He was unaware of the value of placoid distribution on the male antenna as a species character for members of the analis group. On the other hand Williams used male genitalia and I have found them to be very important in the bicolor and burmeisterii groups. The genitalia of species in theanalis group seem identical. The genitalic variablility observed in some bicolor group species is perplexing and needs further study. The shape of the female pygidial plate is diagnostic for some species. I have compared the upper interocular distance (UID) to the lower interocular distance (LID), but there is considerable variablility in some species (20+ specimens measured on average) and overlap between some species. I made my measurements with an ocular micrometer at a magnification of 50X. Figures 1-4 illustrate how these measurements are made, and proper head orientation. Williams (1928) used the lengths of the pedicel and flagellomeres I-II and compared them to the upper interocular distance, but they are not any more reliable or meaningful than UID/ LID comparisons. Character analysis. — In order to assess the relationships of the species involved in this study, and the position of Larra itself within the Larrinae, I have attempted to polarize a number of characters. My outgroup consisted of the other genera of the subtribe Larrina: Liris, Dalara, Paraliris and Dicranorhina, although I have sometimes referred to taxa in the subtribe Tachytina. Bohart and Menke ( 1 976) regarded Larra as the most primitive member of the subtribe Larrina, and Paraliris and Dicranorhina as the most derived. That may be true, but I think that I can now demonstrate that some character states regarded by Bohart and Menke as plesiomorphic in Larra are really apomorphic. In my analysis 0 = the plesiomorphic state, and 1 and 2 - apomorphic states (and do not necessarily represent transformation series). Characters 14-17 were not used in the phylogenetic analysis because they do not appear to be particularly informative, but they are included here because they may merit further study. 1 . Labrum: 0 = flat, not broadly beveled or sloping down at apex, not emarginate; 1 = surface sloping down at apex, or broadly beveled there, free margin arcuate, obtusely angular, or lobate. The plesiomorphic state is apparently universal in the outgroup, in all Old World Larra, and the monotypic burmeisterii group (Fig. 15) in the New World. The apomorphic state is present (Figs. 16- 18, 55) in the bicolor and analis groups of Larra, both restricted to the New World. In the single species of Paraliris available, the labrum is flat, but the free edge is quite thick, and in Dicranorhina and some Liris the labrum has an apical emargination. These represent other apomorphic states. In the Larra bicolor and analis groups it is my assumption that the labrum has become elaborated to aid excavating. 2. Female antennal pedicel: 0 = surface densely setose, similar in appearance to flagellomeres; 1 = dorsum sparsely setose, or asetose, remainder densely setose; 2 = surface largely asetose, polished, constrasting with setose flagellum. The plesiomorphic state appears to be universal in the outgroup, as well as in the New World bicolor group (Fig. 7) and the Old World amplipennis group of Larra. The apomorphic state is universal in the Old World maura group, as well as in the burtneisterii and analis groups (Fig. 8). The pedicel of two Old World Larra is intermediate. In the Australian species L. melanocnemis Turner, the pedicel is more or less asetose dorsally but setose elsewhere. In the Palearctic species L. anathema (Rossi) it is sparsely setose dorsally, and densely setose elsewhere. 3. Placoids of male flagellum: 0 = present on all but the first one or two flagellomeres; 1 = present on only a few flagellomeres; 2 = absent. In the majority of the species of Liris examined, placoids are present on flagellomeres II-XI. Exceptions occur in the subgenus Motes, where some species have only a single placoid, and others have a full complement. In Larra all species have the plesiomorphic condition (Fig. 9) except members of the analis group (Figs. 13, 59-62). The Volume 1, Number 1, 1992 181 Figs. 1-6. Head details of Larra . 1-2, Face showing how to measure lower interocular distance and orientation when doing so. 1, Male of bicolor. 2, Female of altamazonica. 3-4, Top of female head showing how to measure upper interocular distance and proper orientation. 3, bicolor. 4, godmani. 5-6, Details of female vertex of godmani. 5, Ocular sinus along orbit of left eye. 6, Depression behind hindocelli showing pore at bottom. 182 Journal of Hymenoptera Research Figs. 7-9. Antennal features of harm. 7-8. Left female scape, pedicel, and flagellomere I. 7, bicolor. 8, altamazonica . 9, Right male antenna of bicolor. intermediate apomorphic state occurs in the latter group and Dalara. The most apomorphic state occurs onlyinPnra/in'sandD/cranor/nnrt.BohartandMenke (1976) regarded the absence of placoids as plesiomorphic in the Larrinae, but in the subtribe Larrina I think the most logical assumption is that presence of placoids on most flagellomeres is the plesiomorphic condition, and that loss of placoids is the apomorphic condition - a reversal. This is supported by the fact that species and genera in which reduction or complete loss of placoids has occurred are recognizable as derived by other character states. For example, the analis group, which has only 2 to 4 placoids, has an apomorphic labrum, female pedicel, female orbital sinus, and female foretibial carina. 4. Orbital sinus: 0 = absent; 1, present, narrow, 2, present, broad. A deep sinus around the upper orbit of the eye, especially in the female, is apparently absent in the outgroup as well as many species of Larra. A narrow sinus is usually present in the female of the monotypic burmeisterii group (Fig. 49). All members of the analis group and the Old World mama group have a broad, deep sinus (Fig. 4). It is best developed in the female but is present in males as well. The function of this depression (Fig. 5) is unknown. 5. female from: 0 = dull, setose; 1 = polished, largely setose; 2 = polished, largely asetose. In the outgroup the frons beneath the transverse swelling is usually covered fairly densely with setation that obscures the integument which is usually dull. In nearly all female Larra the frons is asetose or nearly so (Fig. 2), the integument easily visible and polished. I regard this as an apomorphy. In the Larra bicolor group the frons is setose at least laterally (Figs. 39-40) but the integument is shiny - this represents an intermediate condition. 6. Female mandible: 0 = cutting edge with one or two subbasal teeth; mandible strongly arched from base to apex, outer surface somewhat angled in cross- section, narrow distad of posterobasal notch and attenuate to apex (pick-like); 1 = cutting edge without teeth; outer surface evenly curved in cross- section, broad beyond posterobasal notch almost to apex (scoop-like). Bohart and Menke (1976, p. 224, 243) considered absence of teeth on the cutting edge to be plesiomorphic in Larra, but I believe that this state is apomorphic since teeth are nearly universally present in the outgroup, one exception being the subgenus Motes of Liris. Teeth are also absent in the specialized genus Parapiagetia, and some specialized species of the genera Gastrosericus and Tachysphex (all subtribe Tachytina). I hypothesize that teeth have some function in prey transport, and because female Larra do not carry their prey, they have lost the teeth. The overall form of the mandible is most often pick-like in the outgroup (Figs. 20-21), but in Larra Volume 1, Number 1, 1992 183 Figs. 10-14. Male flagellar details of Larra showing placoids. 10-12, L. bicolor. 10, Flagellomeres II-V with placoids on III-V. 11, Flagellomeres 1V-V. 1 2, Setal structure of placoids on flagellomeres IV- V. 1 3-1 4, L. analis. 1 3, Flagellomeres Il-VI showing placoids on 1II-V1. 14, Setal structure of placoids on flagellomeres V-VI. 184 Journal of Hymenoptera Research Figs. 15-21. Details of female mouthparts in Larra and Liris. 15-18, Clypeus, labrum and left mandible in Larra. 15, burmeisterii. 16, altamazonica. 17, godmani. 18, bicolor. 19-21, Left mandible. 19, Larra stangei. 20, Liris niger. 21, Liris bembesianus. it is often a broad, scoop-like structure (Figs. 15-17) that I hypothesize has evolved in response to their habit of simply digging down into mole cricket burrows that generally are in damp soil. Presumably the scoop form offers a more efficient digging impliment than a spike-like mandible. Similar scoop-like mandibles occur occasionally in Liris and elsewhere in the subfamily Larrinae. Widening of the area beneath the condylar groove (Michener and Fraser 1978) contributes to the formation of the scoop in some Larra (Figs. 15-17). 7. Mandibular notch: 0 = present, located near middle of mandible; 1 = present, located close to mandible base; 2 = reduced to small V or absent. The function of the mandibular notch is unknown. I (Menke, 1988) came to the conclusion that the absence of a mandibular notch is plesiomorphic in the subfamily. This is clearly the generalized condition in the entire family Sphecidae. However, within the Larrinae notchless mandibles are common only in a few taxa; some examples are: Solierella (Miscophini), most Crabronini, Oxybelus (Oxybelini), and Pison and Trypoxylon (Trypoxylini). Complicating the hypothesis are the apparent reversals scattered through the Larrinae. The notch seems to have been Volume 1, Number 1, 1992 185 reduced or lost in various specialized taxa; examples are found in Liris, Gastrosericus, Holotachysphex, and Tachytes. Clearly the notch in Larrinae needs further investigation. In most members of the outgroup, as well as most genera of Larrinae, the notch is located near the middle of the mandible (Fig. 20), or slightly more basad. In Larra, however, it is clearly subbasal (Figs. 1 5-1 9), due in part to lengthening of the outer part of the mandible. I hypothesize that this has enhanced development of the mandible's scoop- like form. Some Liris with well developed tarsal rakes have elongate mandibles and the notch in these is subbasal (Fig. 21). The mandibular notch is just a small obtuse V in Liris subgenus Liris, and in one species of Paraliris, or is absent just as in Dalara and most Paraliris. The mandible of the latter two genera is otherwise specialized (shape, and extra teeth) which suggests to me that the absence of a notch is a loss feature (apomorphic) in Larrina. The reduction in Liris (Liris) is interpreted similarly. 8. Setae of condylar groove of female mandible: 0 = setae fine, not particularly stiff, not clearly rake- like (Fig. 20); 1 = setae numerous, thickened, stiff, forming a rake (Figs. 18-19, 40); 2 = setae weak, scattered, rake poorly developed (Figs. 15-17). In most Larra the setae in the condylar groove (Michener and Fraser 1978) are numerous, thickened and stiff, forming a rake. Presumably it aids in digging. In the New World analis group the rake setae are widely spaced and rather short (Figs. 16-17). Presumably this condition is a reversal since some species in this group have a well developed scoop-like mandible. Generally in the outgroup the setae are finer and appear less effective as a rake. There are exceptions in Liris (Fig. 21), some species of which excavate very deep nests. 9. Apex of female mandible: 0 = simple; 1 = bidentate. A simple apex is the ground plan condition in the subtribe Larrina, and indeed in the family Sphecidae. However, the apex is bidentate in the female of Dalara and in both sexes of Paraliris (exceptional males of one species lose the condition - see van der Vecht, 1981 ), an obvious apomorphy. At least one species of Liris, tenebrosus (Smith) from South America, also has a bidentate female mandible, but this is not the ground plan in this very large genus. 10. Female foretibial spine rows: 0 = absent; 1 = one row present; 2 = two (Fig. 23) or three present (Fig. 22). In the outgroup the foretibia does not have a row of stout setae except in Liris s.s., a few species of which, principally the non-insular taxa, have a single row. On the basis of other features, the subgenus Liris is a highly evolved lineage, and the foretibial setal row is apparently an apomorphic trait. The African species, Lz'n's {Leptolarra) croesus (Smith), has two rows of setae, one of which consists of two or three setae. Presumbably the spine rows aid in excavating; all Liris with them have well developed foretarsal rakes. In Larra the Old World maura group lacks spine rows, but in the rest of the genus there are two or three rows. Commonly specimens of the bicolor, burmeisterii and analis groups actually have three rows, the innermost one closely paralleling the next and consisting of two to four somewhat finer spines (Fig. 22). Because the rare occurance of one or two spine rows in Liris is obviously not the ground plan condition in that very large genus, it has been omitted from the phylogenetic analysis. Thus in the analysis, condition 1 represents the presence of 2 or 3 spine rows as in Larra. 11. Female foretibial carina: 0 = absent (Fig. 24); 1 = present (Fig. 25). In the outgroup and most Larra the outer apex of the tibia lacks a carina. In the analis and burmeisterii groups however, there is a carina adjacent to the smooth, asetose zone at the apex. I regard this as an apomorphy. 12. Female forebasitarsal asetose zone: 0 = absent (Fig. 26), 1 = present (Fig. 27); 2 = present, extending to apex of segment (Fig. 28). In the outgroup and in the Larra amplipennis group the basitarsus is setose within. Also one species in the Larra bicolor group, stangei, has an entirely setose forebasitarsus (Fig. 26). In the remaining groups of Larra the inner surface of the basitarsus distad of the basal cleaning notch has an impunctate asetose zone of variable length. This zone is a polished strip that attains the apex of the segment in the burmeisterii, analis and maura groups (Fig. 28). I regard this as the the most derived state. An intermediate state is found in the bicolor and anathema groups (Fig. 27), although one species in the bicolor group, stangei, exhibits the plesiomorphic condition. 13. Biology: 0 = captures and paralyzes prey, places prey in previously constructed nest cell and then lays an egg; 1 = temporarily paralyzes host, deposits egg, then flies away, host revives and re- enters burrow, host's burrow functioning as chamber for wasps' pupa. 186 Journal of Hymenoptera Research Figs. 22-28. Details of left front tibia and basitarsus of female Larra. 22-23, Outer surface of tibia. 22, bicolor. 23, godmani. 24-25, Outer surface of tibial apex. 24, bicolor. 25, godmani, showing carina. 26-28, Inner surface of female basitarsus. 26, stangei. 27, bicolor, arrow points to asetose zone. 28, godmani. Bohart and Menke (1976, p. 2, 227, 237) considered the parasitoid-like biology of Larra to be among the most primitive in the Sphecidae. I think however, that a different hypothesis can be made, one that results in Larra' s biology being considered apomorphic in Larrina. I propose that Larra has abandoned the nest preparation habit of its ancestors, and adopted the burrow of its mole cricket host as its nest. Female morphology supports this hypothesis. A pygidial plate is used by larrine wasps as a tamping device during nest closure. Larra has a pygidial plate, but has no apparent use Volume 1, Number 1, 1992 187 for it because these wasps have no nest to seal. I think the plate inLarra is a relic from its nest building ancestors. The only excavating that Larra does is digging into the burrow of the mole cricket host. I hypothesize that the scoop-like mandible and mandibular rake setae common to most female Larra evolved to make them more efficient diggers. The spine rows on the foretibia of many Larra presumably have a similar explanation. Outgroup members, all of which, so far as known, transport prey after paralysis, have teeth on the cutting edge of the mandible (Liris subgenus Motes an exception) that presumably aid in grasping prey. Larra, which does not transport prey, has lost these teeth. The biology of the outgroup is still fragmentary or unknown except in Liris, and even here only a few of the nearly 300 species have been observed (Bohart and Menke, 1976, Kurczewski and Spofford, 1987). But this small data base suggests that the ground plan for the subtribe Larrina is for females to use pre-existing burrows or cavities for nest sites. Morphologically derived taxa like Dicranorhina excavate new burrows that may be maintained for several generations. Excavated burrows may be very deep as in Liris subgenus Lin's. The egg of Larra, at least in some Old World species, is much smaller in comparison to the size of the wasp (1.75 mm for egg, 16-19 mm for wasp) than in Liris, and is glued along most of its linear length to the host, presumably to prevent dislodgement by the mole cricket (Williams, 1928:38), rather than at one end as in other Larrina. If these two traits are apomorphies, they would support my thesis that the biology of Larra is specialized, rather than primitive. Egg size apparently is not always comparatively small, however, since Castner (1988) states that eggs of Larra bicolor are 4.0-4.5 mm long (female wasps range in size from 9.5-20 mm). Also it is not clear from published accounts that Larra eggs are never attached only by one end to the host. The following characters were not used in the phylogenetic analysis. 14. Vertex: 0 = Upper interocular distance more than half as wide as lower interocular distance; 1 = UID less than half as wide as LID. Both states occur in Larra as well as most of the outgroup. Narrowing of the UID is regarded by sphecid workers as an apomorphy in the family. State 1 occurs occasionally in the bicolor and bimneisterii groups too. The apomorphic condition predominates in the analis group and the Old World maura group, both of which have a well developed orbital sinus, another apomorphy. Because of overlap between the two states in nearly each species group of Larra, this character is not particularly informative. Nevertheless, trends are apparent in some groups The vertex has a central U or V-shaped depression just behind the hindocelli which contains a pore-like opening that may have a glandular function (Fig. 6). 15. Pronotal pit (-s): 0 = transversely elongate; 1 = two transversely elongate pits present that are narrowly separated; 2 = two oval pits present. I (Menke, 1988) demonstrated that the presence of some kind of pit or pits on the pronotal midline anteriorly was an apomorphy in Sphecidae. In the Larrina three basic conditions can be defined. The common one in the outgroup is a single, transversely elongate sulcus, but a pair of elongate pits occurs in Dalara and some Liris, particularly the subgenus Liris, although also in a few species of the subgenus Leptolarra. In some Dicranorhina there are two pits narrowly joined by a bridge. All Old World Larra that I have examined have a single, transversely elongate sulcus and so do most members of the New World bicolor group. Theanalis and burmeisterii groups have a pair of separate oval pits (narrowly joined in one species). Polarization here is obviously a difficult decision but I am hypothesizing that paired oval pits is the most derived state in Larrina. 16. Submarginal cell offoreiving: 0 = four sided, 1 = three sided, the inner and outer veinlets joining forming a petiole that reaches the marginal cell (Fig. 45). Petiolation of submarginal cells is widely regarded as a specialization in Sphecidae. All members of the outgroup have the plesiomorphic state, but at least two species of Larra display the apomorphic condition (princeps (Smith) and dux (Kohl). 17. Color of abdomen: 0 = black, 1 = red and black, 2 = red. A black abdomen (and body in general) is the common state in the outgroup. Some species of Dicranorhina, one of the more specialized genera in the subtribe Larrina, have red color on parts of the body. In the large genus Liris, red occurs in very few species and is usually confined to the legs, but rubricatus (Smith), rubellus (Smith) and several others, have a red abdomen. Thus black seems to be the ground plan state, and red a derived condition. A black abdomen is apparently universal in the 188 Journal of Hymenoptera Research Table 1. Data matrix for species groups of Larra and other genera of subtribe Larrina. Taxa Characters 1 2 3 4 5 6 7 8 9 10 11 12 13 Dicranorhina 0 0 2 0 0 0 0 0 0 0 0 0 0 Paraliris 0 0 2 0 0 0 2 0 1 0 0 0 0 D alar a 0 0 1 0 0 0 2 0 1 0 0 0 0 Lin's (Lin's) 0 0 0 0 0 0 2 0 0 0 0 0 0 Lin's (Motes) 0 0 0 0 0 1 0 0 0 0 0 0 0 Liris (Leptolarra) 0 0 0 0 0 0 0 0 0 0 0 0 0 Maura group 0 2 0 2 2 1 0 0 0 2 Amplipennis group 0 0 0 0 2 1 0 1 0 0 Anathema group 0 1 0 0 2 1 0 1 0 1 Analis group 1 2 1 2 2 2 0 2 1 2 Burmeisterii group 0 2 0 1 2 1 0 2 1 2 Bicolor group 1 0 0 0 1 1 0 2 0 1 Larra maura group, although some species have red legs. A mixture of black and red occurs in the amplipennis and anathema groups but I have not seen many species. Larra melanocnemis probably belongs in the anathema group and it is completely black. In the New World, an all red abdomen predominates in the bicolor group although one species has occasional melanic forms. In the other two New World groups the abdomen varies from black to red or a mixture of the two with some species having melanic forms. Color changes may be environmentally induced so the usefulness of color in the phylogeny of Larra is limited. PHYLOGENETIC ANALYSIS AND RESULTS The characters and taxa summarized in the data matrix (Table 1 ), were analyzed using the Hennig86 cladistics program (version 1.5) of Farris (1988). Character 8 was run unordered. Character 10 was run with only two states: 0 = female foretibia without spine rows, 1 = foretibia with two or three spine rows. The ie (implicit enumeration) option resulted in 20 equally parsimonious cladograms, with a length of 28, a consistancy index of 0.71 and a retention index of 0.84. The cladogram reproduced here is representative. The cladogram and strict consensus tree were generated using the Clados program (version 1.0) of Nixon (1991). On the cladogram the black bar represents an apomorphy, the gray bar a parallelism, and the white bar a reversal. The monophyly of Larra was consistantly supported in the analysis by five characters (5, 7, 8, 10, 13). Liris appears to be paraphyletic and the attempt to resolve the relationships of this genus with the rest of the outgroup and Larra explains the numerous cladograms. Within Larra branch swapping occurred between the bicolor and amplipennis groups, and also between the burmeisterii, maura and analis groups. The analysis indicates a reversal of character 1 0 (female foretibial spine rows) in the maura group. As for the outgroups, no stable set of relationships were found except for the grouping of Liris (Liris) + (Paraliris + Dalara), and no group could be reliably determined as the sister group to Larra. The strict consensus tree figured here shows the outgroups forming a polytomy with Larra . Volume 1 , Number 1 , 1 992 189 + icranorhina r— Liris(Liris) 3 3 9 i— jj— Paraliris I— Da Daiara — Liris(Leptolarra) Liris(Motes) + 5 7 8 10 13 I I I I I — §— AmplipennisGroup 12 i— |— BicolorGroup Larra 2 5 I— AnathemaGroup 11 „ , „ i— |— BurmeisteriiGroup 2 4 12 8^ H-+ 4 i— §— MauraGroup — H l 3 8 n 1 1 I I 1 AnalisGroup 4 Representative Cladogram for species groups of Larra and related taxa Dicranorhina Liris(Motes) — Liris(Leptolarra) I— Liris(Liris) Paraliris Daiara AmplipennisGroup — BicolorGroup i— AnathemaGroup I— Da Larra -MauraGroup AnalisGroup — BurmeisteriiGroup Strict Consensus Tree for species groups of Larra and related taxa 190 Journal of Hymenoptera Research KEY TO FEMALES OF LARRA (Facial measurements should be made at 50X) 1. Pedicel densely setose (Fig. 7); outer foretibial apex not carinate (Fig. 24) 2 — Pedicel asetose or nearly so, at least dorsally (Fig. 8); foretibial apex with short carina on outer face (Fig. 25) 4 2. Submarginal cell II petiolate (Fig. 45) princeps (Smith), p. 205 — Submarginal cell II not petiolate 3 3. Pygidial plate broad (Fig. 37), tergum lateral to base of pygidial plate with patch of dense, subappressed setae (Fig. 38); Argentina, Bolivia stangei Menke, p. 202 — Pygidial plate narrow (Fig. 35), tergum lateral to base of pygidial plate at most with few scattered setae (Fig. 36); widespread in South America, Central America bicolor Fabricius, p. 193 and praedatrix (Strand), p. 200 4. Upper interocular distance 0.51-0.56X lower interocular distance (measured tangential to upper edge of tentorial pits), gastral segments I-II red, III-V usually black; southern South America burmeisterii (Holmberg), p. 207 — Upper interocular distance 0.32-0.50X lower interocular distance, gaster color variable 5 5. From eastern North America; UID 0.43-0.50X LID analis Fabricius, p. 210 — From Central and South America; UID 0.32-0.46X LID 6 6. Pygidial plate narrow (Fig. 67); body 13-20 mm long; face with appressed silver setae between antennal socket and eye margin; thoracic pleura usually dull or weakly shiny; mandible apex often broadly rounded (Fig. 17); Mexico to Uruguay godtnani Cameron, p. 212 — Pygidial plate broad (Fig. 68); body 7-13.5 mm long; face sometimes without silver setae; thoracic pleura polished; mandible apex narrowly rounded (Fig. 16); South America altamazonica Williams, p. 215 KEY TO MALES OF LARRA (Facial measurements should be made at 50X) 1. Flagellomeres IV- V, III-V or III-VI with placoids dorsally (Figs. 13, 59-62) 2 — Flagellomeres III-XI with placoids dorsally (Fig. 9) 4 2. Upper interocular distance 0.51-0.57X lower interocular distance; gaster black; combined length of pedicel and flagellomere I 0.86-0.96X UID; North America analis Fabricius, p. 210 — Upper interocular distance 0.38-0.50X lower interocular distance; gaster red, black, or mixture of both; combined length of pedicel and flagellomere I equal to or greater than UID (if not, gaster is red); neotropical 3 3. Only flagellomeres IV-V with placoids (Fig. 61); mesopleuron and propodeal side polished; South America altamazonica Williams, p. 215 — Flagellomeres III-V with placoids (Fig. 60); mesopleuron often dull; Mexico to Uruguay godmani Cameron, p. 212 4. Submarginal cell II petiolate (Fig. 45) princeps (Smith), p. 205 — Submarginal cell II not petiolate 5 5. Labrum truncate or shallowly concave apically, not downflexed at apex (Fig. 15); volsella uniformly densely setose ventrally from base to apex (Figs. 122-123, 125- 126); Argentina, Uruguay, Paraguay burmeisterii (Holmberg), p. 207 — Labrum obtusely angular apically, the angulation downflexed (Figs. 16-18); volsellar setation variable, but always sparser or asetose between base of arms and volsellar base (Figs. 70,74,77,82,90, 110, 117) . . . 6 Volume 1, Number 1, 1992 191 Ventral surface of volsellar arm of genitalia with very long setae on apical half, abruptly changing to very short setae toward base (best appreciated in lateral view, Figs. 88-91); venter of gonostyle with scattered long setae that do not obscure surface (Fig. 84), or surface partially asetose (Figs. 96-1 00), or setation consisting of long fringing setae and shorter, denser setae on surface (Fig. 93) praedatrix (Strand), p. 200 Ventral surface of volsellar arm either with shorter setae (Figs. 73-78), or rather densely covered with moderately long setae (Figs. 81-83, 109-110); gonostyle densely, evenly covered with long setae that obscure surface (Figs. 69, 80, 108) 7 Ventral surface of volsellar arm sparsely covered with short setae that diminish in length basad (Figs. 73-78), shape of volsellar arms typically lyre-like (Figs. 70, 73, 79); widespread in South America bicolor Fabricius, p. 193 Ventral surface of volsellar arm densely covered with moderately long setae (Figs. 109-110), volsellar arms more or less straight (Fig. 109); Argentina, Bolivia stangei Menke, p. 202 BICOLOR SPECIES GROUP Diagnosis. — Male flagellomeres III-XI with placoids (Fig. 9); upper interocular distance in female less than half to more than half length of lower interocular distance (UID 0.44-0.69X LID); transverse sulcus on vertex behind ocelli weakly to moderately impressed at midline; vertex of female head without deep sinus around eye margin (Fig. 3); female clypeus, frons and vertex with considerable dense setation that is often silvery (Figs. 3, 39-40), setae obscuring surface of frons at least laterally (Fig. 39-40); inner surface of female scape densely setose except for narrow asetose zone along anterior (ventral) margin (Fig. 7); female pedicel uniformly setose (punctate) dorsally, the setation less dense than that on flagellomere I (Fig. 34); surface of labrum beveled at free margin or at least sloping down there (Figs. 18, 41), free edge arcuate, angled or lobate; female mandible with long, stout, closely spaced rake setae (Figs. 18-19, 40-41); pronotum anteriorly with transversely elongate sulciform depression at midline, or with two pits (princeps) that are narrowly connected; lower edge of smooth, impunctate area at outer apex of foretibia not sharply carinate in female (Fig. 24); outer surface of female foretibia with row of stout, spine-like setae which often is closely paralleled anterad by row of several finer setae, and more distantly posterad by row of one to three stout setae (Fig. 22), male usually with single row of one to four finer setae; inner surface of female forebasitarsus distad of cleaning notch usually with linear asetose zone at least basally (Fig. 27) but entirely setose in one species (Fig. 26). Included species. — Larra bicolor Fabricius, praedatrix (Strand), princeps (Smith) and stangei n. sp. Discussion . — The numerous placoids of the male flagellum, the setose female scape and pedicel, the strong rake of the female mandible, and the beveled labrum in both sexes, characterize the bicolor group. Only the last two are apomorphies and neither is unique to the group. The bicolor group has no autapomorphies and it is the least specialized of the three New World groups. Among New World Larra only the monotypic burmeisterii group shares the male flagellar character, but female features of that group are similar to the analis group: inner surface of scape largely asetose, pedicel asetose dorsally, vertex with deep sulcus around eye, female frons largely asetose, and foretibial apex with strong carina that is about one sixth length of tibia. The female mandible of the bicolor and burmeisterii groups has a well developed rake, differing in that respect from the analis group. Although somewhat variable, females in the bicolor group have a more extensively and densely setose face, especially the frons, in comparison to the burmeisterii and analis groups In the latter two, the frons is usually nearly asetose and polished. The gaster is always red in the bicolor group except in some specimens of princeps where it may be all black or red and black. The Old World amplipennis group shares some bicolor group characters, but the female forebasitarsus is entirely setose within, the female scape is more broadly asetose within, and the labrum is flat to the apex, not beveled there. The variability of the female forebasitarsus in the bicolor group is noteworthy. The inner surface is setose in stangei n. sp., similar in this respect to the amplipennis group. But the other members of the bicolor group have an asetose zone of variable length within species. The asetose zone is never as extensive as it is in the analis and burmeisterii groups. Two red-abdomened females that I have studied 192 Journal of Hymenoptera Research are problematical. One was collected at San Bernardino, Paraguay (BERLIN). It has a narrow vertex (UID = 0.40X LID) and the inner surface of the forebasitarsus is entirely setose. This specimen is not stangei, the only bicolor group species with a setose forebasitarsus. The second female (USNM) was collected at Olinda, Pernambuco, Brasil. It displays a mixture of bicolor and burmeisterii group characters. As in the latter group the pedicel is asetose and polished, and the forebasitarsus is asetose for most of its length. In other features this specimen agrees with the bicolor group: the foretibia lacks an apical carina, the labrum apex slopes downward, the UID = 0.43X the LID, and the pronotum has an undivided dorsal sulcus. The San Bernardino and Olinda specimens may be freaks, or they may represent undescribed species. Only more material will resolve these problems. The bicolor group contains the most commonly collected neotropical species, but after setting aside princeps, easily identified by its petiolate second submarginal cell, what remains is a taxonomically very difficult group, the bicolor complex. Before I had made a thorough study of the male genitalia, there appeared to be only one species, bicolor. Examination of the genitalia of "bicolor" males from a number of localities in South America revealed that there was considerable variation in volsellar shape and setation and also density of setation of the gonoforceps. My first thought upon realizing how variable the genitalia were in "bicolor" was that it was simply a very plastic species. This hypothesis was enhanced by the fact that females varied also, and I could not find characters that would divide them into two or more "species" reliably. Eventually I dissected every "bicolor" male available, nearly 1500 specimens. The result was the recognition of two more species, praedatrix and stangei. Except for the female of stangei, these three cryptic species can be separated reliably only by characteristics of the male genitalia. The females of the two most widespread species, bicolor and praedatrix, have so far proven inseparable. In attempting to sort females of the bicolor complex to species, I examined the labrum, mandible, clypeus, legs, wings, thoracic sculpture, as well as the features used by Williams (1928). Among the latter are wing color, punctation of the vertex of the head and form of the transverse depressions behind the ocelli, proportions of basal flagellomeres, comparisons of flagellomere lengths and distance between the eyes at the vertex, propodeal sculpture including presence or absence of a median carina, and shape of the pygidial plate. Under scrutiny none of these permitted recognition of more than one taxon. The labrum seems highly plastic. Female wing color varies geographically in the bicolor complex; they may be pale basally, or entirely infumate. The degree of punctation of the vertex varies in females from widely scattered pin prick punctures with a few larger punctures sometimes mixed in, to dense, large punctures separated by less than a puncture diameter. The shape of the vertex depressions noted by Williams vary and thus are not useful to separate species. Various head measurements, often diagnostic in wasps, offered no help in the bicolor complex. For example, the upper interocular distance varies within these species from less than half to three- fifths the length of the lower interocular distance. The proportions of the basal flagellomeres also vary. The median longitudinal carina of the propodeal dorsum varies from present to absent within species, and propodeal sculpture is variable. The shape of the female pygidial plate is somewhat variable, and the only species in which it appears to be useful at the species level is stangei. Before reaching the conclusion that females of bicolor and praedatrix were truly inseparable, I examined material that was collected at the same location and date as known males of these species. If females of both species were present, I can only conclude that they are unrecognizable. I had a large sample of bicolor complex material from Saavedra, Bolivia in which males of bicolor and praedatrix were nearly equally numerous, 343 and 304 specimens, respectively. There were 500 females, but I could not separate them into two species. I also studied laboratory reared material from Saavedra sent by Fred Bennett, University of Florida, Gainesville, Florida. He had Fl and sometimes F2 offspring from females and all material was correlated by numbers. Male progeny from the mothers offered positive means of associating males and females of bicolor and praedatrix. I had hoped that this material would permit detection of characters for separating females of these two species, but such was not the case. All but one of the 14 females proved to be bicolor based on male offspring, and the 13 specimens of bicolor amply demonstrated how variable the head punctation and other characters are in that species. Features of the single female of praedatrix fell within the variation of bicolor. Volume 1, Number 1, 1992 193 Larra bicolor and praedatrix are largely sympatric in South America and often occur together. The genitalia of bicolor vary a little over the range of the species, but variation in praedatrix is bewildering (see Figs. 84-107). Further study of praedatrix may indicate that it is a complex of cryptic species, but laboratory rearing of material and sophisticated techniques like cuticular hydrocarbon studies may be required to resolve this. Finally, I have 39 males, all from Venezuela, whose genitalia are fairly similar to stangei, a new species from southern Bolivia and northwestern Argentina whose female is fairly reliably separable from bicolor and praedatrixby the form of the pygidial plate and associated setation. Presumptive females of the Venezuelan taxon are, however, inseparable from those of bicolor /praedatrix, and it may be that the male genitalia simply represent an extreme variant of bicolor. This is another problem for future study. The absence of female differences poses a critical nomenclatorial problem: the lectotype of bicolor, the oldest name, is a female. I have arbitrarily interpreted bicolor as the species that was introduced to Puerto Rico and later Florida. The treatment of younger names based on females has also been problematical, and these are discussed under bicolor and praedatrix. The species treatments that follow, with the exception of princeps, are based largely on male characters because of the female problems discussed above. A composite female description for bicolor/ praedatrix is presented under the bicolor treatment that follows. Larra bicolor Fabricius Figs. 1, 3, 7, 9-12, 18, 22, 24, 27, 29-36, 39, 69-79 Larra bicolor Fabricius, 1804:221. Lectotype female: "America meridionali" (COPENHAGEN), designated by van der Vecht (1961:17). Tachytes pagana Dahlbom, 1843:132. Holotype male: "insula St. Crucis" (= St. Croix, Virgin Is.) (BERLIN). Synonymy by Patton (1881:389). Type examined by Stadelmann (1897:255). Larrada americana Saussure, 1867:74. Lectotype male: Caracas, Venezuela (GENEVA), present designation. Synonymy by Patton (1881:389); van der Vecht (1961:17). LarrarfflgflsfricrtTaschenberg, 1870:5. Lectotype male: "Parana", [Brasil or Argentina] (HALLE), designated by Menke (in Bohart and Menke, 1976:238). NEW SYNONYM. Larra guiana Cameron, 1912:433. Holotype female: Guyana (BMNH). NEW SYNONYM. Larra scapteriscka Williams, 1928:58. Holotype female: Belem, Brasil (BISHOP). NEW SYNONYM. Male description. — (951 specimens of which 343 are from Saavedra, Bolivia). Male identifiable only by genitalia: ventral surface of gonoforceps densely covered with uniformly long setae that obscure surface (Fig. 69); ventral surface of volsellar arms sparsely setose, in lateral profile all setae are fairly short although those at apex are longest and there is a gradual shortening of the setae basad (Figs. 75, 78), toward the base of the of the volsellar lobe the setae are restricted to outer area (Figs. 70, 73, 76, 79); in ventral view margins of volsellar arm broadly sinuate, the apex usually acuminate and curving away laterad (Figs. 70, 73, 79); outline of apicodorsal crest of volsellar arm highly variable in lateral profile. UID0.54-0.73X LID; vertex behind ocelli variably covered by large punctures (Figs. 29-30) that are crowded (separated by a puncture diameter or less), or more widely spaced (separated by 2-4X a puncture diameter, usually unevenly so); transverse impression behind ocelli variable, often forming an angle at midline, the angle often terminating in a pit, sometimes with median sulcus or impression beyond angle that may reach rear edge of vertex; labrum usually arcuate, but free edge occasionally straight, surface of labrum usually impunctate as it slopes down to setose free edge, occasionally slope is punctate. Propodeal dorsum usually with median, longitudinal carina on basal one third or fourth, occasionally extending to apex, sometimes nearly absent. Forewing from base to level of stigma paler (clear to yellowish) than infuscate apex; submarginal cell II variable in shape, but very rarely petiolate on marginal cell. Gaster red; tergum VII with or without lateral angle or carina delimiting a pygidial plate; sternum VIII variable, apex notched or rounded. Length 8-14 mm. Discussion. — The volsella nearly always identifies males of bicolor. The somewhat lyre-like form of the two volsellar lobes with their attenuate apices and rather sparse, short setation ventrally are unique. Occasionally the lobes are atypically narrow (Figs. 76, 79), and sometimes the apices are somewhat blunt and not divergent (Fig. 76), but the sparse, short setation is still distinctive. To really appreciate the shortness of the volsellar lobe setation the structure should be viewed in lateral profile (Figs. 75, 78). In the sibling species praedatrix the volsellar lobes vary in shape and sometimes resemble those of bicolor, but the setae on the apical half are very long and abruptly change to very short setae beyond that point (Figs. 89-91). In bicolor the 194 Journal of Hymenoptera Research Figs. 29-30. Vertex of male head of bicolor from Puerto Rico showing variation in punctation. setae gradually shorten from apex to base. Furthermore, the gonostyle in praedatrix is never covered densely by the uniformly long setae found in bicolor. In stangei the volsellar lobes are straight and densely covered ventrally by long setae (Figs. 109-110). I have 39 males (MARACAY, USNM, FSDA, CORNELL) from several localities in Venezuela (Map 4) whose status is unresolved. The volsellar setation is similar to that of stangei (Figs. 81-83), but the lobes are lyre-like as in bicolor (Fig. 81), and the gonostyle setation is like bicolor (Fig. 80). Putative females of these Venezuelan specimens are not stangei. Thus the Venezuelan males may represent a new species, or an extreme variant of bicolor. The latter hypothesis is supported by 12 males that I collected in 1985 at Hato Masaguaral south of Calabozo, Venezuela (USNM). Three are typical bicolor, ten represent the unresolved taxon, and one has volsellar setation that is somewhat intermediate. Variation in the upper interocular distance is fairly random geographically, but the shortest UlD's occur in the smallest specimens. Likewise, the density of vertex punctation, development of the propodeal carina, etc. are also random. The shape of forewing submarginal cells varies and occasionally the inner and outer veinlets of II meet on the marginal cell. In one male from Paraguay (CSDA) these two veinlets form a very short petiole before reaching the marginal cell. Female description. — (1158 specimens of which 500 are from Saavedra, Bolivia). The following descriptive notes apply to females of bicolor and praedatrix since they are indistinguishable. UID 0.46-0.63X LID; transverse impression behind ocelli usually deeply, obtusely angular, but occasionally weakly impressed or absent, in the latter a small circular fossa remains where apex of angle would be; vertex punctation varies from very sparse pin prick punctures with scattered larger punctures to very dense macropunctation (Figs. 31-33); labrum typically flat with deflexed thickened apex (Fig. 18) that varies from impunctate or punctate, sometimes with prominent corners in the latter, outline of free margin highly variable; pronotum with transversely elongate sulciform depression anteromedially (also present in male); propodeal dorsum with median carina of varying length, or carina absent; forewing bicolored (clear basad of stigma) or uniformly infuscate; submarginal cells II and III variable in shape; gaster Volume 1, Number 1, 1992 195 Figs. 31-34. Female head features olbicolor. 31-33, Vertex showing punctation behind ocellar triangle. 31, Specimen from Puerto Rico. 32, Specimen from Campinas, Brasil. 33, Specimen from Entre Rios, Argentina. 34, Dorsal surface of pedicel and flagellomere I. red except pygidial area blackish in occasional specimens from Argentina; pygidial plate typically narrow, weakly convex (Fig. 35), but rarely broader and nearly like stangei; tergum lateral to pygidial plate typically only with scattered, long, erect setae that usually become sparser toward base (Fig. 36), occasionally, however, some shorter, subappressed setae are clustered near base as in stangei (some material from Paraguay). Length: 9.5-20 mm. Discussion of female variation. — Some variation is geographic. Bicolored wings are typically found only in females from Mexico; El Salvador; parts of Colombia, Peru, Venezuela, and French Guiana; the lower Amazon drainage (east of Santarem in Para); Puerto Rico; and Florida. Dark wings predominate south of the Amazon Basin, but 196 Journal of Hymenoptera Research Figs. 35-38. Sixth gastral segment of female Larra. 35-36, L. bicolor. 35, Pygidial plate. 36, Lateral view of right side showing setation. 37-38, L. startgei. 37, Pygidial plate. 38, Lateral view of right side showing setation. material from Guatemala, Costa Rica, Trinidad, the Guianas, and parts of Colombia, Peru and Venezuela usually have evenly infumate wings. The type and density of punctation on the vertex more or less coincides with wing color. Most female wasps with evenly infumate forewings have dense macropunctation on the vertex. Exceptions to this rule occur in Venezuela, Trinidad, the Guianas, Peru, Mato Grosso in Brasil, Paraguay and Argentina where the vertex may have sparse pin Volume 1, Number 1, 1992 197 ;;■:< m m^m mm* M ?9i i MAP 1 bicolor 8 3tf w... iena,iyj. Obl>qu* Co«.e Conlo.mol 198 Journal of Hymenoptera Research prick punctation with scattered larger punctures in dark-winged females. Punctation intergrades occur everywhere of course. Occasional specimens have a broad pygidial plate or have a cluster of shorter, subappressed setae lateral to it basally, as in stangei, but I have not seen specimens with both conditions. Distribution based on males (Map 1) and females (Map 2). — Widespread in South America: Colombia to about the 38th parallel in Argentina. Also Trinidad, Puerto Rico (introduced) and Florida (introduced). I have seen no males of bicolor from Central America, so all the female records from there (Map 2) may pertain to praedatrix. Florida material. — Larra bicolor was first liberated at Gainesville, Tampa, and Fort Lauderdale, Florida in 1981 (Hudson et al., 1988). The following year additional releases were made at Bradenton and Lakeland, but the species only became established at Fort Lauderdale. The introduced wasps were collected around Isabella, Puerto Rico. In 1 988-1 989 Bolivian material of "bicolor" from Saavedra was liberated at sites in Alachua County, Florida (Bennett et al., 1990), but according to Fred Bennett (personal communication) the wasps apparently did not become established. Floridian females have the sparse pin prick punctation on the vertex typical of Puerto Rican material, the latter the offspring of wasps collected originally around Belem, Brasil ( Wolcott, 1 941 ) . The Fort Lauderdale population has not spread much according to Fred Bennett. I have studied a single female collected at Watson's Hammock, Big Pine Key in Monroe Co., Florida on August 28, 1986 by S. & J. Peck (ALBERTA). This female is puzzling because it has moderately dense punctation on the vertex, and the punctures are intermediate between pin pricks and macropunctation similar to material from Mexico and parts of Central America. It has bicolored wings just like the Fort Lauderdale material, but the denser head punctation suggests that this female is not offspring from the Fort Lauderdale population. Possibly it represents a chance introduction from Central America or an undetected native population. Positive identification of the Big Pine Key female as bicolor will have to await capture of males. Type notes. — I have not examined the lectotype of L. bicolor designated by van der Vecht (1961 ), but I have studied the material that he compared with it (USNM, LEIDEN). From van der Vecht's (1961) notes and the appearance of his homotypes, it is clear that the lectotype has bicolored forewings ("with faint yellow tinge . . . outer half slightly darker"). The vertex of the head posterior to the ocelli is very sparsely covered with a mixture of pin prick and regular punctures, the latter far fewer in number. The propodeum has a median longitudinal carina on basal half, and the tegula is amber colored. I am arbitrarily interpreting Fabricius' type as conspecific with the male that I call bicolor. I have examined a male specimen bearing a handwritten label "Larrada pagana Dahlb" . The label does not closely resemble the two examples of Dahlbom's handwriting illustrated by Horn and Kahle (1937), but it is similar to the example of Stadelmann's writing in the same work. The locality label on the pin says "Brasilien" which disagrees with Dahlbom's stated origin for the specimen ("ex insula St Crucis dedit Amic. Sommer in Altona mense Julio 1838"). Thus there is doubt about this specimen being the type of pagana. On the other hand, Larra apparently did not occur in the West Indies until bicolor was introduced to Puerto Rico by Wolcott in 1936 (see Wolcott 1936), and I have seen no material from St. Croix or any other Caribbean island except Trinidad. Thus Dahlbom either gave erroneous locality information or his type specimen was mislabeled. In any event, the genitalia of the presumed type of pagana are typical for bicolor, and I regard Stadelmann's (1897) synonymy as correct. Saussure's Larrada americana was described from three females and a male from Caracas, Venezuela, and a female from "Brasilia". He had an additional female from "Cayenna" that he tentatively treated as a "var.". I have examined the Caracas material, all housed at the museum in Geneva, and the male is a typical bicolor; I have labeled it as lectotype. Its genitalia fall within the limits of bicolor. The other specimens have not been located. Taschenberg (1870) described gastrica from two males and three females that were taken at three different localities: Parana, Panda oriental (an area in Minas Gerais, Brasil), and Venezuela. I designated (Menke 1976:238) a male from Parana as lectotype. I presume that Parana refers to the state in Brasil, but there is also a city, Parana, in Entre Rios, Argentina. The genitalia of the lectotype fall within the limits of bicolor. The holotype of Larra guiana Cameron is a female with uniformly infumate forewings. The vertex of the head is sparsely covered with a mixture of pin prick and regular punctures, the tegula is amber colored on its posterior half, and the propodeal dorsum has a median carina on its basal third. Cameron's label reads "Larra guyana Cameron, Brit. Volume 1, Number 1, 1992 199 MAP 2 bicolor/praedatrix 9 200 Journal of Hymenoptera Research Guyana", but the name is spelled guiana in the original description. Synonymy of guiana with bicolor is presumptive because the type is a female. The holotype of scapteriscica Williams appears to be only a small example (11.3 mm. long) oibicolor, but it could also be praedatrix. The vertex punctation is similar to that described for the types of bicolor and guiana. But there is no trace of a carina on the propodeal dorsum of the type, or in five of the six topotypical female paratypes, but one of the latter has a long carina. The genitalia of the two topotypical male paratypes are missing unfortunately. Williams' (1928) description and figure suggest that they were not of the typical bicolor type. Larra praedatrix (Strand) Figs. 84-107 Notogonia praedatrix Strand, 1910:159. Holotype male: CalleS. Miguel, in Asuncion, Paraguay (BERLIN). NEW COMBINATION. Larra paraguayana Strand, 1910:158. Holotype female: Calle San Miguel in Asuncion, Paraguay (BERLIN). NEW SYNONYM. Notogonia gastrifera Strand, 1910:160. Lectotype male: Villa Morra, [Asuncion], Paraguay (BERLIN), present designation. NEW SYNONYM, new combination. Larra pacifica Williams, 1928:55. Holotype female: Bucay, Ecuador (BISHOP). Provisional NEW SYNONYM. Male description. — (479 specimens, of which 304 are from Saavedra, Bolivia). Male identifiable only by genitalia. Typical form as follows: ventral surface of gonostyle with widely spaced, long setae of variable length, those along the margins longer than most of those on the ventral surface, and increasing in length toward base (Figs. 84-85); ventral surface of volsellar arms sparsely setose, in lateral profile those on apical half very long, abruptly changing to very short setae basad (Figs. 88-91); in ventral view outer margins of volsellar arms straight, the arms converging (Fig. 85). Variations from this typical form are many (Figs. 92-107), but most share one diagnostic feature, the very long setae on the apical half of the volsellar arm that abruptly change to very short setae beyond; in a few males, however, the long volsellar setae continue all the way to the base of the arm or nearly so (Figs. 92-95). Sometimes the volsellar arms are much narrowed and straight (Figs. 1 00-1 0 1 ), or as in bicolor they may curve outward somewhat at the apex, but the latter is usually rounded (Fig. 107). The lateral profile of the volsellar arm crest varies considerably (Figs. 89, 102, 104, 106), and the apex may be sharp (Figs. 88, 94) or rounded (Fig. 107). Most genitalic variants involve gonostyle setation. Sometimes the gonostyle has a narrow asetose zone along the inner margin (Fig. 96). This is often accompanied by an increase in the overall density of setation with setae along the center of the gonostyle being uniformly shorter, sometimes considerably shorter, than those along the margins (Fig. 97). Sometimes the asetose area includes most of the ventral surface of the gonostyle (Figs. 98-100). UID 0.52-0.73X LID; vertex similar to bicolor, labrum usually arcuate but free edge sometimes lobe-like, surface of labrum impunctate as it slopes down to setose free edge, occasionally slope is punctate. Propodeal dorsum without or with median longitudinal carina of variable length. Forewing paler between base and stigma than infuscate apex; submarginal cell II not petiolate. Gaster red; tergum VII with or without lateral angle or carina delimiting pygidial plate; sternum VIII variable, apex notched or rounded. Length 7.5-15 mm. Discussion. — Although there is considerable plasticity in the male genitalia, the volsellar arm setation is usually diagnostic: the setae on the apical half are very long, abruptly changing to very short setae beyond (Figs. 89-91). In some specimens the long setae continue to the base of the arm or nearly so, but they are always restricted to the inner margin of each arm (Fig. 94). Such specimens occur in Costa Rica, and the Brasilian states of Para, Bahia and Espirito Santo. Occasional specimens of bicolor and stangei with similar volsellar arm setation have been mentioned under those species treatments, but they have uniformly long, dense setation on the venter of the gonostyle. The occasional males of praedatrix with long setae nearly to the volsellar arm base have sparser gonostyle setation characteristic of this species. Specimens with a narrow asetose zone on the gonostyle (Figs. 96-97) occur in Guatemala, El Salvador, Costa Rica, Colombia, Ecuador, and Argentina. Largely asetose gonostyles (Figs. 98-100) have been noted on specimens from Guatemala, Costa Rica, Bolivia, Mato Grosso and Ceara in Brasil, Paraguay, and Argentina. The great variation in gonostyle setation (Figs. 84, 93, 96-100) is perplexing and there is no correlation with variation in volsellar form and setation. The various volsellar types described and illustrated here occur with most of Volume 1, Number 1, 1992 201 Ofaltqua ''..jr.,.. Conlo.n., 202 Journal of Hymenoptera Research the different gonostyles, not just those shown in the SEM figures. There are so many intermediates that I have been unable to identify more than one species. Nevertheless, future work may indicate that praedatrix consists of several sibling species. On the other hand, it is still possible that praedatrix may prove to be conspecific with bicolor. If so, the latter would be an unusually plastic species in terms of male genitalia. Female. — Indistinguishable from bicolor. See that species for particulars. Distribution based on males (Map 3). — Known from the state of Vera Cruz in Mexico to Buenos Aires Province in Argentina, but apparently mostly absent from the Amazon Basin. Larra praedatrix is largely sympatric with bicolor in southern South America, but seems to replace the latter species in Central America and the lower slopes of the northern Andes. Type notes. — Bohart and Menke (1976) incorrectly listed praedatrix under the genus Liris. Strand's (1910) holotype is a Larra, and was probably collected with the females of piaragnayana; all have similar locality labels. The male genitalia of the holotype of praedatrix are identical to figures 84-87. Strand (1910) tentatively identified two female specimens from Paraguay as Larra rnbricata Smith, a red abdomened species now placed in the genus Liris; he also provisionally named these specimens as "L. paragnayana" in the event that they should prove to be distinct from rubricata. Strand indicated that the larger specimen was the "Type". The holotype was collected June 10, 1906. I have examined both females and am assuming that the holotype is conspecific with the holotype of praedatrix. As first revisor, I have selected praedatrix for the name of this species because it is based on a male. Notogonia gastrifera Strand was described from three males all from the same locality. I have selected and labeled one as lectotype. Its genitalia are of the typical ^rat'rfflfn'.t type. It was collected Nov. 9, 1905; the other two were collected Jan. 3, 1 906. Bohart and Menke (1976) incorrectly listed gastrifera under the genus Liris. The holotype of Larra pacifica Williams is a female from Bucay, Ecuador. His paratypes, all males from Tena, Ecuador, are praedatrix. Since I have no authentic males of bicolor from Ecuador, but quite a few of praedatrix , I am tentatively synonymizing pacifica with praedatrix. Larra stangei Menke, new species Figs. 19, 26, 37-38, 40-44, 108-111 Description of male. — (11 specimens). Separable from other members of the bicolor complex only by genitalia (Figs. 108-1 11): ventral surface of gonostyle densely covered with uniformly long setae that obscure surface (Fig. 108); ventral surface of volsellar arms densely, uniformly covered with long setae (Fig. 109); in ventral view, outer margin of volsellar arm straight (Fig. 109); apicodorsal crest of volsellar arm not or only slightly incurved in dorsal view. UID 0.63-0.69X LID. Vertex behind ocelli with transverse impression that does not form an obtuse angle at midline, macropunctate, punctures nearly contiguous. Labrum impunctate, surface smoothly sloping down to free margin. Median longitudinal carina of propodeal dorsum sometimes absent, but usually extending to apex. Wings uniformly infumate in Argentine specimens, forewing bicolored and hindwing largely pale in Bolivian material; second submarginal cell of forewing not petiolate. Gaster red; tergum VII with broad, flat pygidial plate delimited by sharp lateral carinae (Fig. 44); sternum VIII with shallow apical V-notch (Fig. 44). Length 11-14 mm. Female.— (17 specimens). UID 0.53-0.57X LID; transverse impression behind hindocelli obtusely angular, vertex densely bipunctate, macro- punctures much more numerous (Figs. 43); surface of labrum flat, sharply truncate apically, free edge thickened and forming prominent deflexed lobe (Figs. 41-42); pronotum anteriorly with transversely elongate sulciform depression at midline (also present in male); inner surface of forebasitarsus without asetose zone distad of cleaning notch (Fig. 26); propodeal dorsum with or without median, longitudinal carina; gaster red, tergum VI with broad pygidial plate that is flat on apical half, and whose margins are cariniform on apical half (Fig. 37), surface of tergum lateral to plate apex with many long, stiff setae that become shorter, denser and more appressed toward base (Figs. 37-38); wings uniformly infumate in Argentine specimens, forewing bicolored and hindwing largely pale in Bolivian specimens. Length 13.5-18.5 mm. Discussion. — The densely setose volsella is the most diagnostic male feature of stangei although some male Larra from Venezuela have similar genitalia. In the Venezuelan material, however, the volsellar lobes curve outward apically in ventral Volume 1, Number 1, 1992 203 Figs. 39-44. Features of bicolor group. 39-40, Female face. 39, bicolor. 40, stangei. 41-42, Labrum and associated structures in female of stangei. 41, Oblique view of mandible and labrum (arrow points to deflexed apical lobe of labrum). 42, Closeup of labrum. 43, Female vertex of stangei showing ocelli and postocellar punctation. 44, Male tergum VII showing pygidial cartnae, apex of sternum VIII visible below. 204 Journal of Hymenoptera Researo of- ?0 MAP 4 stangei = • bicolor/stangei intergrades =0 30 Wait Longitude Smilhion.an Imt.tuhon 1983 Volume 1, Number 1, 1992 205 view (Fig. 81 ), just as in bicolor, and these specimens may be variants of that species and not stangei (see bicolor treatment). The broad, flat female pygidial plate of stangei is distinctive in this sex (Fig. 37), but by itself is unreliable because of variation in this structure in bicolor /praedatrix. Usually, however, the latter do not have short, dense, subappressed setae on the side of the tergum (Fig. 38), or if they do, the plate is narrow. In older, worn female specimens of stangei the subappressed setae may be abraded, but their pits are still visible. The absence of a clearly demarked asetose zone on the forebasitarsus (Fig. 26) is another apparent character of females of stangei, but in view of the variation in the development of this zone in the other species of the group, and the small sample size for stangei, the reliability of this character is unknown. Two males from Rosario de Lerma, Salta, Argentina (CSDA, FRITZ) have puzzling genitalia. In one the volsella has long setae along the inner part of each arm from apex to base, but they are not as dense as in stangei, and laterally the setae are shorter. The apicodorsal crest of the volsellar arm is somewhat higher than the average condition in stangei, and it curls inward strongly in dorsal view. In the other specimen the volsellar setation is typical of stangei but the volsellar arm is constricted subapically and the apicodorsal crest is sinuate and incurved. In view of the genitalic variation in other species, these two specimens probably are stangei, but I have not included them among the paratypes. Curiously a third male collected at the same place is a typical bicolor (CSDA). Etymology. — I take pleasure in naming this wasp after my long time friend, Lionel Stange, who collected nearly half of the known material. Distribution '(Map 4). — North western Argentina, southern Bolivia. Types.— Holotype male: BOLIVIA, Santa Cruz: Sand dunes at El Palmar Oratorio, about 40 kms southeast of Santa Cruz, Jan. 25, 1980, Lionel A. Stange (FSDA). Paratypes: BOLIVIA, Santa Cruz: same data as holotype, 5 males, 4 females, L. A. Stange (FSDA, USNM); Santa Cruz, one male, Feb. 10, 1971, M. Fritz (FRITZ). ARGENTINA, Salta: Alemania, one male, five females, Feb. /Mar. 1983, M. Fritz (FRITZ); La Vina, one male, three females, Dec.,Feb. 1983-1984, M. Fritz, M. Wasbauer (FRITZ, CSDA); Tartagal, two males, three females, Nov. 1971 , M. Fritz (FRITZ); Guachipas, one female, Feb. 1989 (FRITZ); Coronel Moldes, one female, Feb. 1990 (FRITZ). Larra princeps (Smith) Figs. 45-46, 112-119 Larraxena princeps Smith, 1851:30. Lectotype female: "Brazil" (BMNH), present designation. Description. — (126 males, 124 females): Male UID 0.50-0.62X LID; female UID 0.44-0.50X LID (as measured tangential to upper edge of antennal sockets). Male vertex behind ocelli with transverse impression that is usually deeply, triangularly depressed at middle; deep groove often extending posterad from apex of this depression; macropunctate, punctures nearly contiguous to one diameter apart. Female vertex similar except no groove extending posterad from triangular depression and punctures varying from fine to coarse and often separated by 2 or 3 puncture diameters. Labrum impunctate in both sexes, surface smoothly sloping down to free margin that has a few marginal punctures. Pronotum anteriorly with pair of oval pits that are usually narrowly connected. Propodeal dorsum carina usually extending nearly to apex, but sometimes much shorter or even absent. Wings evenly infumate with rare exceptions; second submarginal cell petiolate on the marginal cell (Fig. 45), petiole rarely very short or absent (Fig. 46). Gaster black or red, sometimes red with black areas at tergal and sternal margins; female tergum VI and pygidial plate same as bicolor; male tergum VII without pygidial carinae; male sternum VIII variably emarginate apically; ventral surface of gonostyle uniformly covered with dense, long setae that obscure surface (Fig. 112); volsellar arms broad, densely covered with long setae ventrally that obscure surface (Figs. 112, 116- 1 1 7); apicodorsal crest of volsellar arm not incurved in dorsal view (Fig. 118). Males 9-16 mm long, females 13-20 mm. long. Discussion . — The petiolate second submarginal cell immediately identifies princeps. I have seen two Argentine females in which the cell is not petiolate on one wing (Fig. 46), so it is likely that rare individuals might have non-petiolate cells in both wings. Separation of them from bicolor / praedatrix should be possible by the presence of two pronotal pits. The male genitalia of princeps are fairly uniform and quite distinctive, particularly the broad volsellar arms that are densely covered with setae (Figs. 116-117). Larra princeps is the only species in the bicolor group that has two color forms. All black specimens 206 Journal of Hymenoptera Research MAP 5 princeps 0 = red gaster 0= black gaster occur mainly in the southern part of the species' range, but both color morphs occur together especially along the eastern side of the Andes in Argentina (Map 5). Red morphs predominate, however. Exceptions to the darkly infumate wings occur in Peru and Entre Rios Prov. in Argentina where the wings are paler toward the base and the infumation is less dense. Distribution (Map 5). — Larra princeps is a commonly collected species in Argentina, but the species appears to have a fairly wide distribution in South America based on a few scattered records in Peru, Venezuela and Brasil. Type notes. — I have examined the two female syntypes described by Smith in 1851. Both have a red abdomen and typical wing venation. I have Volume 1, Number 1, 1992 207 placed my lectotype label on the specimen that already had a circular "type" label. BURMEISTERII SPECIES GROUP Diagnosis. — Male flagellomeres HI-XI with placoids; upper interocular distance in female at least half length of lower interocular distance; transverse sulcus on vertex behind ocelli weakly to moderately impressed at midline; vertex of female head usually with narrow, deep sinus around eye (Fig. 49); female frons beneath transverse swelling polished, nearly impunctate and largely asetose except at level of antennal sockets, clypeus laterally, and vertex (Fig. 47); inner side of female scape largely asetose, with only few scattered setae basally (Fig. 48); female pedicel asetose dorsally and ventrally, polished, at most with a few scattered setigerous punctures (Fig. 48); labrum flat, at most narrowly downflexed at midapex (Fig. 15); female mandible with numerous long, stout rake setae (Fig. 1 5); pronotum anteriorly with pair of oval pits at midline; lower edge of smooth, impunctate area at outer apex of female foretibia margined by sharp carina that extends about one sixth tibial length (Fig. 51 ), male with much shorter carina; outer surface of female foretibia with row of stout, spine-like setae that often is closely paralleled anterad by row of several finer setae, and more distantly posterad by row of one or two stout setae (Fig. 50), male usually with single row of one or two fine setae; inner surface of female forebasitarsus distad of cleaning notch with asetose linear zone that extends to apex (Fig. 52). Included species. — Larra burmeisterii (Holmberg). Discussion. — This group displays a curious mixture of characters. The male has a plesiomorphic antenna just like the bicolor group. The female, however, shares several apomorphic features with the analis group (asetose pedicel, asetose inner surface of scape, frons largely asetose and polished, sinus present around upper margin of eye, and carinate foretibial apex). The ocular sinus is not as pronounced as in the analis group and it represents and intermediate condition. The upper interocular distance in the female of burmeisterii is broader than in the ana/is group. Apomorphies of the burmeisterii group include the shiny, asetose female pedicel, the female ocular sinus, the shiny asetose and nearly impunctate female frons, the moderately well developed female mandibular rake setae, the pair of pronotal pits, the foretibial carina in both sexes, and the asetose linear area on the inside of the female forebasitarsus. None are unique to the group. The female pedicel of the Old World species anathema (Rossi), the type species of Larra, approaches the condition found in burmeisterii. It is polished dorsally but the surface is sparsely setose, and the outer and ventral surfaces are densely setose. The inner surface of the female scape of anathema is polished and largely asetose just as in burmeisterii. The female of anathema lacks a deep sinus around the upper margin of the eye, the foretibial carina is absent, and the forebasitarsus has only a vaguely defined asetose area basally. Both sexes of anathema have a flat labrum just like burmeisterii, however. The Australian L. melanocnemis Turner, which probably belongs in the anathema group, shares most of the latter's features but the female forebasitarsus has a distinct asetose zone. The gaster in burmeisterii may be red, black or combinations of both colors. Larra burmeisterii (Holmberg) Figs. 15, 47-52, 120-127 Larrada burmeisterii Holmberg, 1884:221. Holotype female: Colonia, Paraguay (destroyed). Description.— (72 males, 183 females): Male UID 0.60-0.66X LID; female UID 0.51-0.56X LID (as measured tangential to upper margin of tentorial pits). Male vertex behind ocelli with weakly to strongly impressed angular depression at midline posterior to which is a narrow, linear impunctate zone; macropunctate, punctures about a diameter apart or less. Female vertex with strong angular depression behind ocelli, and sometimes with narrow, linear impunctate zone posterior to it, this area often somewhat elevated even if punctate; punctures nearly contiguous posteriorly but becoming sparser toward transverse impression, sometimes impunctate and polished next to it (Fig. 49). Labrum scarcely projecting beyond clypeus, especially in male, polished, impunctate, flat to free margin although sometimes indented there at midline, apex slightly arcuate, truncate or shallowing emarginate (Figs. 15, 47). Propodeal dorsum carina present and of variable length, or more frequently absent. Wings darkly infumate in female, clear or weakly infumate in male; second submarginal cell of forewing not petiolate. Male 208 Journal of Hymenoptera Research -jC~. 45 46 Figs. 45-46. Left female forewing of Larra princeps. 45, Wing with normal petiolate second submarginal cell. 46, Wing with aberrant second submarginal cell (right wing is normal). Figs. 47-49. Larra burmeisterii, features of female head . 47, Face. 48, Inner side of scape, pedicel and flagellomere I of left antenna. 49, Vertex. abdomen all red or all black, but sometimes first two or three segments are red, the remainder black; female abdomen sometimes all red, but usually segments I-II and VI red, III-V black, or occasionally segments I-III red, remainder black; female tergum VI and pygidial plate similar to that of bicolor; male tergum VII usually with pygidial carinae, sternum VIII usually notched apically but sometimes entire; ventral surface of gonostyle densely covered with long setae that obscure surface (Fig. 120), volsellar arm of uniform width to rounded apex (Fig. 124), or constricted subapically (Fig. 121), entire venter of volsellus densely covered with long setae (Figs. 121-126); apicodorsal crest of volsellar arm variable in lateral profile (Figs. 123, 126). Males 8.5-13.5 mm long, females 11-18.5 mm long. Discussion. — The male of burmeisterii is reliably identified only by genitalic characters, primarily the completely setose volsella (Figs. 122-123, 125- 126). The flat, non-beveled labrum is useful, but often the labrum is concealed in dead material. The female can be identified by the polished, nearly asetose pedicel and the broad upper interocular distance (equal to at least half the lower interocular distance). Color is also useful. No other species within the range of burmeisterii has a bicolored abdomen, but some specimens ha ve an all red or all black gaster. The ocular sinus varies. In some females it is barely evident. Males with a completely black gaster come from the provinces of Rio Negro, Buenos Aires, Entre Rios and Corrientes. Females with an all red gaster occur in the Argentine provinces of Rio Negro, Buenos Aires, Mendoza, and Tucuman as well as in Uruguay. Bicolored forms are known from all but Rio Negro and Tucuman, however. Distribution (Map 6). — Larra burmeisterii is widespread in Argentina and Uruguay, and occurs as far south as the Rio Negro. I have a single record from Paraguay, and several from Rio Grande do Sul in southernmost Brasil. I have seen a single female labelled Santiago, Chile (VIENNA) but I presume that this is erroneous. Type notes. — The holotype was destroyed by Volume 1, Number 1, 1992 Figs. 50-52. Larra burmeisterii, features of female foretibia and tarsus. 50, Outer surface of tibia. 51, Outer apex of tibia showing carina. 52, Inner surface of basitarsus. museum pests long ago, but Holmberg's (1884) description is sufficient to identify the species. The first three gastral segments were red in the type, the remainder black. This agrees with some of the females that I have seen from Uruguay. Although Holmberg used a Lynch Arribalzaga ms. name, burmeisterii, the description is Holmberg's. Apparently Lynch Arribalzaga was preparing a revision of the Argentine "Larrada" but it was never published. 209 ANALIS SPECIES GROUP Diagnosis. — Placoids restricted to male flagellomeres III-VI (Figs. 13, 59-62); upper interocular distance of female less than half length of lower interocular distance (UID 0.32-0.46X LID); transverse sulcus on vertex behind ocelli usually deeply impressed at midline; vertex of female head with broad, deep sinus around eye (Figs. 4, 63-65), male with shallower sinus; female frons beneath transverse swelling polished, variably punctate, largely asetose except at level of antennal sockets, clypeus laterally, and vertex (Figs. 2, 53); inner surface of female scape largely asetose except at base (Fig. 8); female pedicel almost entirely asetose (only a few scattered setae), surface smooth, polished (Fig. 8); female mandible with poorly developed rake, setae scattered, weak (Figs. 16-17, 56, 58); labrum beveled or sloping down at apex to obtusely angular or arcuate free margin (Figs. 16- 17, 55-58); pronotum anteriorly with pair of oval pits at midline that sometimes are narrowly connected; lower edge of smooth, impunctate area at outer apex of female foretibia margined below by sharp carina that extends about one-sixth tibial length (Fig. 25), male without carina; outer surface of female foretibia with row of stout spine-like setae that is occasionally closely paralleled anterad by row of several finer setae, and more distantly posterad by row of one to three stout setae (Fig. 23), male usually with single row of one to four finer setae but sometimes absent; inner surface of female forebasitarsus distad of cleaning notch with asetose linear zone that extends to apex (Fig. 28) . Propodeal dorsum usually without median longitudinal carina, or with only a remnant, but occasional specimens have complete carina. Male tergum VII without pygidial carinae. Male genitalia essentially identical in all species: ventral surface of gonostyle densely covered with long setae (Fig. 1 28); volsellar arms straight, broadening distally, ventral surface with long setae (Fig. 129); apicodorsal crest of volsellar arm sinuate in dorsal view (Fig. 130). Included species. — Larra altamazonica Williams, analis Say, and godmani Cameron. Discussion. — The presence of placoids on just a few of the basal male flagellomeres is an autapomorphic feature of the analis group. In all other Larra placoids are found on flagellomeres III- XI. In the female, the combination of a polished, impunctate pedicel, the narrow upper interocular distance (less than 0.50X LID), the deep impression at the midline of the vertex, and the deep sinus around the upper eye margin, and the weak mandibular rake set the analis group apart from other New World Larra, but of these apomorphies, 210 Journal of Hymenoptera Research 30 Wtil Longilud* Smithionmn Init.tuhon 19B3 only the weak mandibular rake is unique to the group. Females of the Old World maura species group share the other apomorphies, but the outer face of the foretibia in that assemblage has no spine rows or an apical carina, and the labrum is flat, without an apical bevel. The female frons in the maura group apparently is always asetose and is essentially impunctate beneath the tranverse swelling, a trait shared with one species of the analis group, altamazonica. In the other two species of the analis group, the frons, though shiny, is clearly punctate. Species characters are few in this group. The number of flagellomeres with placoids is useful in males, but there is some intraspecific variation. Unfortunately, male genitalia seem identical in the three species. Because of this, identification of occasional males of altamazonica and godmani with atypical antennal placoid distribution can be problematical. The length of the UID in relation to the LID is useful to some extent in both sexes, but there is some overlap between species. The shape of the female pygidial plate is diagnostic for altamazonica. Color in the analis group is constant in analis,butaltamazonica and godmani have forms with a black gaster, and forms with a red gaster, or combinations of both. Larra analis Fabricius Figs. 13-14, 53, 55, 59, 63, 66, 128-131 Larra analis Fabricius, 1804:220. Holotype female: Carolina. (PARIS). Type studied by van der Vecht (1961:17). Larrada canescens Smith, 1856:292. Holotype male ("female"): Georgia. (BMNH). Synonymy by R. Bohart (in Bohart and Menke, 1976:237). Volume 1, Number 1, 1992 211 Figs. 53-58. Female head features in analis group. 53-54, Face. 53, analis. 54, altamazonica. 55-58, Clypeus, labrum and mandible. 55, analis. 56, godmani. 57-58, altamazonica. 212 Journal of Hymenoptera Research Larrada americana Cresson, 1872:21 4. Holotype male: Texas [presumably BosqueCo.].(ANSP). Junior secondary homonym of Larra americana Saussure, 1867. Synonymy by G. Bohart (1951:953). Larra cressonii I >x, 1 894:482. New name for americana Cresson. Description. — (181 males, 273 females): Male UID 0.51-0.57X LID; female UID 0.43-0.50X LID (as measured tangential to upper margin of tentorial pits); punctures of male vertex separated by about one diameter on disk, closer peripherally; female vertex punctures similar to male, but sometimes 3 or 4 diameters apart discally (Fig. 63); female frons finely punctate; placoids present on male flagellomeres III-V, and sometimes VI, lengths of placoids variable on III and VI (Figs. 13, 59); surface of labrum gradually curving down to free margin in male, more sharply beveled in female (Fig. 55); apex of female mandible narrowly rounded (Fig. 55). Pronotal pits narrowly connected. Mesopleuron dull or weakly shining. Wings evenly, darkly infumate. Propodeal dorsum usually delimited posterad by transverse carina. Male gaster black, terga sometimes with silvery apical fasciae; female gastral segments I-III black, IV- VI red. Male sternum VIII rounded at apex, often indented there; female pygidial plate narrow (Fig. 66). Male 8.5-14.5 mm long, female 12.5-18.5 mm long. Discussion. — Larra analis is the only Nearctic species and it has a non-varying color pattern that permits easy identification. Males are all black and females have a black gaster with the last three segments red. Occasional melanic females of godmani from South America have the last three segments of the gaster red and thus resembleflHfl/»s, but the UID is narrower in the latter species. The UID in melanic godmani ranges from 0.32-0. 39X the LID, while the UID in analis ranges from 0.43-0.50X the LID. Males of analis generally have a broader UID than either godmani or altamazonica. In analis the UID is 0.51-0.57X the LID. In the other two species the male UID ranges from 0.35-0.50X the LID. Distribution (Map 7). — Widespread in the eastern United States from about the 104th meridian to the southern and eastern coasts. Northward analis apparently does not extend beyond the 43rd parallel, Livingston Co. in Michigan and Taunton, Massachusetts being the northernmost records seen. The wasp is evidently uncommonly collected except in the southern tier of states. Type notes.— J. van der Vecht (1961), R. Bohart (in Bohart and Menke, 1976), and G. Bohart (1951) studied the types of analis, canescens, and americana, respectively, and I accept their interpretations. Cresson (1872) described americana from a single male which is now in Philadelphia (see Cresson, 1916). Thus the male in the U. S. National Museum of Natural History collected by Belfrage in Texas and labeled as "type" is a pseudotype. Larra godmani Cameron Figs. 4-6, 17, 23, 25, 28, 56, 60, 64, 67 Larrada aethiops Smith, 1873:56. Lectotype female: "St. Paulo" (= Sao Paulo de Olivenca, Amazonas) Brasil (BMNH), present designation. Junior primary homonym of Larrada aethiops Cresson, 1865. Larra godmani Cameron, 1889:49. Lectotype female: Orizaba, Mexico (BMNH), present designation. NEW SYNONYM. Larra braunsii Kohl, 1898:351. Lectotype female: Santos, Brasil (State of Sao Paulo) (VIENNA), present designation. NEW SYNONYM. Larra transandina Williams, 1928:56. Holotype female: Tena, Ecuador (BISHOP). NEW SYNONYM. Description. — (290 males, 186 females): Male UID 0.35-0.50X LID; female UID 0.32-0.46X LID (as measured tangential to upper margin of tentorial pits); punctures of male vertex separated by less than a diameter to more than a diameter on disk, closer peripherally; female vertex irregularly punctate, punctures scattered, less than diameter apart to several diameters apart, punctures sometimes very fine, almost pinprick-like and widely separated, the vertex almost impunctate (Fig. 64); female frons finely punctate, occasionally almost impunctate; placoids typically present on male flagellomeres III-V (Fig. 60), flagellomere III rarely without placoid, placoid on III usually occupying apical half, that on V usually occupying basal two thirds or more; surface of labrum gradually curving down to free margin (Figs. 17, 56); apex of female mandible broadly rounded (Figs. 17, 56) or narrowly rounded. Pronotal pits separate. Mesopleuron usually dull or weakly shining, infrequently shiny. Wings darkly infumate, except sometimes paler at base. Propodeal dorsum sometimes delimited apically by transverse carina. Gaster all red or all black (19% of male and 17% of female specimens melanic), occasional red male specimens have tergum I suffused with black, occasional black specimens of both sexes have last two or three segments red. Male sternum VIII with apical emargination, or rounded and /or weakly Volume 1, Number 1, 1992 213 Figs. 59-62. Male flagellomeres III-V or VI showing placoids. 59, analis. 60, godmani. 61 , altamazonica (typical). 62, altamazonka. notched. Female pygidial plate narrow (Fig. 67). Males 8-13.5 mm long, females 13-20 mm long. Discussion. — The presence of placoids on male flagellomeres III-V of godmani differentiates the species from males of altamazonica. But I have seen one red gastered specimen of godmani without a placoid on flagellomere III (Darien, Panama (Quintero). Positive identification of such specimens can be problematical. In the case of the Panamanian wasp, a typical male was taken at the same time and place, thus verifying its identity as godmani. Also it has rather dull mesothoracic pleura typical of godmani. I have also seen two melanic males without a placoid on flagellomere III (FSDA, MCZ) that I regard as godmani based on body length and rather dull mesothoracic pleura. The shape of the female pygidial plate (Fig. 67) is the most reliable character for separating godmani from altamazonica. The latter species has a broader plate (Fig. 68). The frons below the transverse swelling is usually very finely punctate in females, at least in part. In altamazonica the female frons is nearly impuncate or the punctures are largely effaced. The thoracic pleura of godmani are duller compared to altamazonica which tends to have shiny pleura. Males of godmani with an all red gaster are quickly separated from males of analis, all of which have a black gaster. The narrower male UID of godmani, especially those with an all black gaster, generally distinguishes this sex from anal is. The UID ranges from 0.35-0.43X the LID in black males of godmani, while in analis the range is 0.51-0.57. Females with a red gaster are easily separated fromanalis, but the occasional melanic godmani with the terminal segments red must be indentified by measuring the upper interocular distance. In melanic godmani the UID ranges from 0.32-0.39X the LID; in analis the UID is 0.43-0.50X the LID. Of course the two species are allopatric. In about half of the godmani females studied, the apex of the mandible is more broadly rounded than inanalis or altamazonica (compare Figs. 56, 58), but in all material studied from Mexico, the northern end of the 214 Journal of Hymenoptera Research r#n W 0 ■";f"^-f ^^-->j.-S-i>^ Figs. 124-127. Volsellar details of male genitalia of burmeisterii (specimen from Montevideo, Uruguay). 124, Ventral view. 125, Oblique ventral view. 126, Lateral view. 127, Dorsal view. 234 Journal of Hymenoptera Research Figs. 1 28-131. Male genitalia of 0.05). PREY Podalonia robusta females preyed upon soil-dwelling, larval Noctuidae. A single paralyzed cutworm was placed in each cell. Prey were de- termined as follows: Aletia oxygale (Grote) (1), Apamea sp. (2), Caemtrgina erechtea Grote (1 ), Eupsilia devia (Grote) (2), Euxoa sp. (2), Lacanobia subjuncta (Grote & Robinson) (2), Protorthodes oviduca (Guenee) (3), ? Protorthodes sp. (1 ) and Pseudorthodes vecors (Guenee) (1). Cutworm prey ranged in wet weight from 166 to 698 (mean = 330.1, N = 24) mg and the female wasps weighed 56-83 (mean = 73.8, N = 6) mg. The mean weight of prey to wasp ratio was 4.5: 1. EGG Each egg of P. robusta was attached by its ante- rior end to the abdominal midline of the prey; the posterior end of the egg extended away from the midline of the prey's body (N = 17). Live eggs ranged from 3.0 to 4.0 (mean = 3.6, N = 3) mm long and from 0.8 to 0.9 (mean = 0.9, N = 3) mm wide. They were placed on the left (6) or right (11) sides of the cutworm and were affixed to the first (1), second (2), third (5), fourth (8) or fifth (1 ) abdominal segments. CLEPTOPARASITISM Females of P. robusta were trailed and their prey or entrances larviposited on/within by three spe- cies of Miltogrammini: Senotaiuia trilirwata (Vander Wulp), S. vigilans Allen and Sphenometopa tergata Meigen (Spofford and Kurczewski 1990). One cut- worm attacked during prey transport contained 12 238 Journal of Hymenoptera Research maggots of S. vigilans. Two wasps attracted three S. vigilans while fighting with each other. The first female went off hunting trailed by one fly and the second left hunting trailed by the two other flies. Another S. vigilans followed a wasp during prey transport and attempted twice to larviposit on the cutworm. After the P. robusta cached her prey, the fly perched motionless on a plant nearby. As the wasp walked away, searching for a place to dig a burrow, the fly followed her and ignored the cached cutworm. One wasp, whose prey was larviposited upon by an S. trilineata during transport, did not exit from her nest after placing the cutworm inside. During excavation of the nest, several minutes later, she was observed resting atop the prey which was in a curled, C-position in the cell. There was no wasp's egg on the cutworm. We believe that the wasp was in the process of cleaning maggots from the prey when we unearthed her, but prey cleaning has not been substantiated for species in this genus. DISCUSSION In many genera of Sphecidae, certain behavioral characteristics apply to all or most congeners, and species of Podalonia are no exception. Key differ- ences exist between species of Podalonia as to: (1) whether adult females overwinter; (2) whether the wasps construct burrows before or after capturing prey; and, (3) kinds of prey. Murray (1940), based upon Newcomer's (1930) and Hicks' (1931) obser- vations and his own collecting records, concluded that some adult females of P. communis and P. luctuosa overwinter. Females of several European species of Podalonia are also believed to overwinter (Roth 1928, Maneval 1939, Grandi 1961). O'Brien and Kurczewski (1982) marked P. luctuosa females with paint in late summer and recaptured some of them the following spring to confirm overwinter- ing in this species. According to the present study, adult females of P. robusta do not overwinter. At least two species of Nearctic Podalonia, valida (Steiner 1975) and, sometimes, occidentalis (Evans 1987) dig their burrows before they hunt for prey. This behavior has also been reported in two exotic species of the genus (Tsuneki 1968, Bohart and Menke 1976). The advantages and disadvantages of digging the burrow before prey capture have been reviewed by Evans and West-Eberhard (1970) and Iwata (1976). P. robusta invariably dug its burrow after capturing prey, in our observations of 27 wasps. The majority of species of Podalonia prey upon hairless, nocturnal-feeding, noctuid larvae (Bohart and Menke 1976, Krombein 1979). P. valida, in contrast, hunts diurnal "wooly bears" of the genus Estigmene (Arctiidae) (Steiner 1974), and P. occidentalis is a specialist on tent caterpillars of the genus Malacosoma (Lasiocampidae) (Evans 1987). Williams (1928) noted that P. violaceipennis also captured tent caterpillars in California, but it is likely that he, too, was observing P. occidentalis (Evans 1987). Balduf (1936) reported that P. violaceipennis hunts mature larvae of the notodontid Symmerista albifrons S. & A., but his report may have involved misidentification of the wasp. Roth (1928) observed P. hirsuta Scopoli preying upon gypsy moth larvae (Lymantriidae) in Europe. That three species of Podalonia capture hairy, arboreal, lepidopterous larvae and numerous other species prey upon hairless, nocturnal-feeding cutworms is a difference that provides the basis for further study of prey selection in the genus. ACKNOWLEDGMENTS We thank D.J. Peckham, SUNY Health Science Center at Syracuse, for use of his note on cleptoparasitism of P. robusta, T.L. McCabe, NY State Museum, Albany, and G. Godfrey, Illinois Natural History Survey, Urbana for identifying the species of prey, A.S. Menke, Systematic Entomology Laboratory, ARS, USDA, for confirming the identity of the wasp species, and W.L.Downes, Jr., Michigan State University, for confirming the cleptoparasitic fly identifications. LITERATURE CITED Balduf, W.V. 1936. Observation on Podalonia violaceipennis (Lep.) (Sphecidae) and Vespula maculata (L.) (Vespidae). Canadian Entomologist 68: 137-139. Bohart, R.M. and A.S. Menke. 1976. Sphecid Wasps of the World. A Generic Rei'ision . University of California Press, Berkeley . 695 pp. Evans, HE. 1987. Observations on the prey and nests of Podalonia occidentalis Murray (Hymenoptera: Sphecidae). Pan-Pacific Entomologist 63: 130-134. Evans, H.E. and M.J.W. Eberhard. 1970. The Wasps. University of Michigan Press, Ann Arbor. 265 pp. Grandi, G. 1961. Studi di un entomologo sugli Imenotteri superiori. Bollettino deli Istituto di Entomologia dell' Universita di Bologna 25: 141-144. Hager, B.J. and F.E. Kurczewski. 1986. Nesting behavior of Ammophila harti (Fernald) (Hymenoptera: Sphecidae). Psyche 116: 7-24. Hicks, C.H. 1931. On the digger wasp, Podalonia luctuosa (F. Smith). Pan-Pacific Entomologist 8: 49-51. Iwata, K. 1976. Evolution of Instinct. Comparative Ethology of Hymenoptera. Amerind Publishing Company, New Delhi, India. 535 pp. Krombein, K.V. 1979. Genus Podalonia, pp. 1586-1588. In Krombein, K.V., P.D. Hurd, Jr., DR. Smith, and B.D. Volume 1, Number 1, 1992 239 Burks, eds. Catalog of Hi/menoptera in America North of Mexico. Vol. 2. Apocrita (Aculeata). Smithsonian Institution Press, Washington, DC. Maneval, H. 1939. Notes sur les Hymenopteres. Annates de la Societe Entomologique de France 108: 49-108. Murray, W.D. 1940. Podalonia (Hymenoptera: Sphecidae) of North and Central America. Entomologica Americana 20: 1-84. Newcomer, E.J . 1 930. Notes on the habits of a d igger wasp and its inquiline flies. Annals of the Entomological Society of America 23: 552-563. O'Brien, M.F. 1989. Distribution and biology of the sphecine wasps of Michigan (Hymenoptera: Sphecidae: Sphecinae). Great Lakes Entomologist 22: 199-217. O'Brien, M.F. and F.E. Kurczewski. 1982. Ethology and overwintering of Podalonia luctuosa (Hymenoptera: Sphecidae). Great Lakes Entomologist 15: 261-275. Roth, P. 1928. Les Ammophiles de l'Afrique du Nord. Annates de la Societe Entomologique de France 97: 153-240. Spofford, M.G. and F.E. Kurczewski. 1990. Comparative larvipositional behaviours and cleptoparasitic frequencies of Nearctic species of Miltogrammini (Diptera: Sarcophagidae). Journal of Natural History 24: 731-755. Steiner, A.L. 1974. Unusual caterpillar-prey records and hunting behavior for a Podalonia digger wasp; Podalonia valida (Cr.). Pan-Pacific Entomologist 50: 73-77. Steiner, A.L. 1975. Description of the territorial behavior of Podalonia valida (Hymenoptera: Sphecidae) females in southeast Arizona, with remarks on digger wasp territorial behavior. Quaestiones Entomologiae 11: 113-127. Tsuneki, K. 1968. The biology of Ammophila in East Asia. Etizenia 33: 1-64. Williams, F.X. 1928. The sphecid wasp, Podalonia violaceipennis (Lep.). Proceedings of the Hawaiian Entomological Society 7: 163. J. HYM. RES. 1(1), 1992 pp. 241-253 Biological and Taxonomic Studies of Chartocertis subaeneus (Hymenoptera: Signiphoridae), a Hyperparasite of Mealybugs David Rosen, Yael Argov, and James B. Woolley (DR, YA) The Hebrew University, Faculty of Agriculture, P.O. Box 12, Rehovot 76100, Israel; (YA) The Israel Cohen Institute for Biological Control, 27 Keren Kayemet St., Rehovot 76345, Israel; (JBW) Department of Entomology, Texas A&M University, College Station, Texas 77843-2475, U.S.A. Abstract. — Chartocerus subaeneus (Foerster), an obligatory direct hyperparasite of mealybugs, is redescribed and its developmental stages are described and illustrated. A lectotype is designated. This deuterotokous species develops ectoparasitically on fully developed larvae and pupae of various primary encyrtid parasites in mummified mealybugs. When reared on Tetracnemoidea peregrina (Compere) in the long-tailed mealybug, Pseudococcus longispinus (Targioni Tozzetti) at 28°C, females lived for 25 days and oviposited throughout their lifetime. Fecundity was high, averaging 163 eggs per female or 6.8 eggs per day. Adult females host-fed regularly, and this prolonged their life span considerably. They were susceptible to low relative humidity. Development from egg to adult emergence took 16.4 days. The developmental threshold was 14.8°C, and the thermal constant was 221.5 days-degrees. The biology of hyperparasitic Hymenoptera has been relatively little studied (see Rosen 1981, Sullivan 1 987 and Viggiani 1 990 for recent reviews) . Of the Signiphoridae known as hyperparasites, only two species have been studied in any detail: Chartocerus elongatus (Girault) by Clausen (1924) and Signiphora coquilletti Ashmead by Woolley and Vet (1981). Somewhat more information is avail- able on the biology of Signiphoridae acting as primary parasites, all of which are species of Signiphora that attack armored scale insects. Quezada et al. (1973) provide the most complete biological information for any signiphorid in their study of Signiphora borinquensis Quezada, DeBach and Rosen, DeBach et al. (1 958) and Agekyan ( 1 968) providedetails for Signiphora merceti Malenotti, and Woolley (1988, 1990) reviews the remaining avail- able information. A little-known hyperparasitic signiphorid, Chartocerus subaeneus (Foerster), was found to overwhelm mass cultures of Tetracnemoidea peregrina (Compere) (Hymenoptera: Encyrtidae) during a highly successful campaign for biological control of the long-tailed mealybug, Pseudococcus longispinus (Targioni Tozzetti) (Homoptera: Pseudococcidae), which was the cornerstone of an effective integrated pest management program on avocado in Israel (Swirski et al. 1980, Swirski and Wysoki 1988). In field samples, on the other hand, this hyperparasite was quite rare. A study of its taxonomy and biology was undertaken in order to contribute to our knowledge of hyperparasites and signiphorids. MATERIALS AND METHODS Chartocerus subaeneus was originally obtained from a laboratory mass culture at the Volcani Cen- ter, Bet Dagan, Israel. Cultures of the hyperparasite were maintained at 28±1°C and >50% RH, in ven- tilated plastic cages, 15 x 25 x 35 cm or so, with Tetracnemoidea peregrina serving as primary host and the long-tailed mealybug, Pseudococcus longispinus, infesting sprouting potatoes, as sec- ondary host. Both the primary and secondary (mealybug) hosts were reared at the Volcani Cen- ter on sprouting potatoes, at 26±2°C and >65%. Material for description of adults and develop- mental stages was obtained from the laboratory cultures. In biological experiments, parasitized mealybug mummies were glued to small cards (2.5 x 3 cm) with neutral glue (Sachinata Mucilage Glue, Japan) and presented to newly-emerged wasps in small plastic cups. Unless stated other- wise, all experiments were held at 28±1°C and >50% RH, and the wasps were provided with honey streaks for food. TAXONOMY The genera of Signiphoridae have recently been reviewed by Woolley ( 1 988), who provides a key to 242 Journal of Hymenoptera Research genera and species groups, diagnostic characteris- tics, discussions of various anatomical characters, and hypotheses for phylogenetic relationships. Rozanov (1965) treated Chartocerus as containing three subgenera, and referred C. subaeneus to the subgenus Signiphorina. Woolley (1988) provided evidence for monophyly of Chartocerus and the nominate subgenus, but was unable to find evidence for monophyly of the other two subgenera. Chartocerus is in need of revision on a worldwide basis, and consequently most species are difficult to identify. Chartocerus subaeneus is most closely related toelongatus (Girault), novitzkyi Domenichini, fimbriae Hayat, and intermedins Hayat. Novitzky (1954) redescribed and figured subaeneus, Domenichini (1955) compared subaeneus with elongatus and novitzkyi, and Hayat (1970, 1976) compared subaeneus with fimbriae and intermedins. We have determined the identity of our material based on examination of Foerster's types, the lit- erature, and comparison with specimens deter- mined by Sugonyaev and Ferriere. In addition to Israel, Chartocerus subaeneus is reported from Western Europe, the European part of the U.S.S.R., Turkey and Soviet Central Asia. In view of the inadequate state of the systematics of this group, a detailed redescription is presented for future reference. ADULT MORPHOLOGY Terminology for anatomical structures follows Woolley (1988). In particular, mesosoma refers to thorax plus propodeum, metasoma refers to the abdomen posterior to the propodeum, and num- bering of terga and sterna (e.g., T2, S2) refers to metasomal terga and sterna. The apparent ninth tergum in females is called the epiproct for reasons discussed by Woolley (1988). Chartocerus subaeneus (Foerster) Plastocharis subaenea Foerster 1878, Verh. Nat. Ver. Preuss. Rheinl. 35: 69. Thysanus subaenea: Dalla Torre 1898, Catalogus Hymenopterorum, Lipsiae 5: 223. Signiphorina mala Nikol'skaya 1950, Dokl. Akad. Nauk SSSR 75: 19-21. Signiphorina subaenea: Novitzky 1954, Ann. Fac. Agr. (N.S.) 2: 245-255. Signiphora (Signiphorina) subaenea: Peck et al. 1964, Mem. Entomol. Soc. Can. 34: 90-91. Chartocerus (Signiphorina) subaeneus: Rosanov 1965, Entomol. Obozr. 44: 878. Diagnosis. — Inasmuch as Chartocerus is in need of comprehensive revision, it is no doubt prema- ture to attempt to distinguish subaeneus from all species with which it might be confused. It appears to be most similar to C. elongatus, C. novitzkyi, C. fimbriae and C. intermedins. In subaeneus, the medial denticles of the male genitalia are robust, curved and long, extending approximately half the length of the digiti, and they are inserted on a strongly sclerotized region between the bases of the digiti (Fig. 26). The medial denticles in elongatus are less robust, straight, and shorter (about 1 /3 the length of a digitus), and they are not inserted on a sclero- tized region (cf. Fig. 4.8, Domenichini 1955). In novitzkyi, the medial denticles are long and straight, almost the length of a digitus, and a sclerotized region is not apparent at their bases (cf. Fig. 4.9, Domenichini 1955). According to Hayat (1970, 1976), fimbriae and intermedins can be distinguished from subaeneus by the longer marginal fringe on both fore and hind wings, and the yellow middle tibiae of all legs (middle and hind tibiae are black in proximal half in subaeneus). Female. — General coloration shining black; an- tennae dark brown; eyes and ocelli black; all tarsi yellowish, fore tibiae pale, middle and hind tibiae black in proximal half and pale distally, other segments of all legs black. Fore wing with alter- nating, broad hyaline and dark bands (Fig. 13). Hind wing hyaline. Length 0.95-1.15 mm. Head (Figs. 3, 8) with frontovertex broad, wider than long, transversely striate, bearing sparse short setae. Cheek length not exceeding 2/3 length of eye. Face longitudi- nally striate, bearing sparse short setae. Eyes with sparse, short inter-ommatidial setae. Ocelli in an obtuse triangle; the posterior pair at about their own diameter from inner orbits. Antennal toruli (Fig. 3) about their own diameter from oral margin; scrobes convergent, the area between them not elevated. Mandibles bearing long setae, the two denticles subequal in length, the dorsal one somewhat truncate. Maxillary palpi (Fig. 7) 2-segmented, api- cal segment the longest, bearing an apical spine; labial palpi 1-segmented, bearing an apical spine and a subapical seta. Antenna (Figs. 1, 2) 7-seg- mented ( 1 1 41 ), all but the first 3 funicular segments bearing short setae. Radicle bearing a few sensory setae at base. Scape 4.8 - 6.5 times as long as wide. Pedicel 2.0 - 2.75 times as long as wide, usually 1.5 - 2.0 times as long as funicle. First funicular seg- Volume 1 , Number 1 , 1 992 243 Figs. 1-7. Chartocerus subaeneus. 1 , Female antenna. 2, Female antennae: pedicel, funicle and base of club (SEM). 3, Head, frontal view; antennae removed to show toruli and scrobes (SEM). 4, Male head and antennae. 5, Male antennal funicle (SEM). 6, Female presternum, ventral pronotum, prepectus, and mesepisternum in ventral view; fore coxae removed (SEM). 7, Female mouthparts, ventral aspect, showing maxillae and labium (SEM). 244 Journal of Hymenoptera Research merit minute, 6-7 times as wide as long; second and third segments subequal in length, twice as long as the first, 2-4 times as wide as long; fourth segment about 1 /3 as long as the third, 1 .7 - 3.0 times as wide as long. Club 5.0 - 9.3 times as long as wide, 1.5-1.6 times as long as scape and about 6 times as long as funicle, bearing 4-6 longitudinal sensilla, 0.26 - 0.32 length of club, and several fingerlike sensilla at tip. Mesosoma (Figs. 8-10) transversely imbricate, bearing sparse short setae. Pronotum usually 2/5 length of mesoscutum in dorsal view, bearing a transverse row of short setae along posterior mar- gin. Mesoscutum 2.3-3.0 times as long as scutellum, bearing 6-19 setae, those in postero-lateral corners larger. Scutellum bearing a row of 7-12 short setae along posterior margin, with a pair of submedian discoid sensilla. A pair of lateral internal costulae on scutellum, visible only in cleared slide mounts (compare Figs. 8 and 9), set off the triangular ap- parent axillae, each of which bears a single large seta. Metanotum with medial portion faintly stri- ate and devoid of setae; lateral lobes smooth except for some reticulation near margins, each bearing a pair of minute setae. Propodeum (Figs. 9, 10) length 0.6 - 0.8 greatest width, 0.55 - 0.72 length of mesoscutum, 1 .66 - 1 .75 times as long as scutellum, 2.5 - 3.5 times as long as metanotum; smooth lat- erally, rather faintly reticulate mesad of spiracles, with medial sclerite triangular and strongly re- ticulate, apex not quite reaching posterior propodeal margin. Prepectus fused with ventral mesepisternum; the membrane between it and the prosternum, underneath the fore coxae, bearing numerous papillae (Fig. 6). Metasoma (Figs. 9, 12) subequal in length to the head and mesosoma combined. First tergum ( = second abdominal) (Figs. 9, 10) short, smooth, weakly bilobed, not overlapped by propodeum; T2-T6 reticulate, bearing 4-9 setae on each side, with a discoid sensillum anterad of each setiferous area; T2 the longest; T7 (Fig. 25) bearing a transverse row of 8 setae, with a pair of submedian discoid sensilla between the spiracles; T8 (Fig. 25) repre- sented by a narrow transverse plate and two lateral lobes bearing the cerci, each with two long setae and one short seta; epiproct rhomboid. Sixth ster- num almost at apex of metasoma and distinctly bilobed medially. Second phragma (Fig. 12) 1.53 - 1.87 times as long as wide, reaching well beyond base of ovipositor to level of fifth tergum . Ovipositor nearly twice as long as middle tibia (1.80 - 1.98); ovipositor sheaths longitudinally striate. Tarsi of all legs pentamerous (see Fig. 1 2); strigil (Fig. 15) well developed; middle femur (Fig. 16) bearing 2 or 3 long spines postero-apically, one short apical spine, and a row of short setae dorsally; middle tibia bearing 2 long setae and 2 shorter setae dorsally, in addition to numerous short setae; mid-tibial spur (Figs. 16, 17) 4/5 length of corre- sponding basitarsus or more (0.78 - 0.93), bearing a row of 4-5 teeth. Fore wing (Fig. 13) about 3 times as long as wide (2.8 - 3.1 ); longest marginal cilia 1 /2 - 2/3 width of disk. Submarginal vein 3/4 to nearly as long as marginal vein, bearing 2 setae and 13 bullae; mar- ginal vein bearing 4 long setae along anterior margin and 4-5 short ventral setae; stigmal vein about 1 /5 length of marginal vein, bearing a single seta and 3 discoid sensilla. Costal cell bearing a single dorsal seta; disk otherwise bare except for 5-7 minute ventral setae below junction of submarginal and marginal veins. An oblique fold near center of disk, beginning below apex of venation. Hind wing (Fig. 14) about 5 times as long as wide (4.1 - 5.5); longest marginal cilia 3/4 width of disk or more (0.75 - 0.93); disk bare except for one short seta below apex of marginal vein. Marginal vein bearing one long proximal seta followed by 2- 5 shorter setae, 2 hamuli and 3 straight spines at apex. Male. — Similar to female in structure, chaetotaxis, sculpture and coloration, differing mainly in antennal and genital characters. Antenna (Fig. 4) six-segmented (1131). Scape as in female; pedicel more pyriform, 2.0 - 2.5 times as long as funicle; funicular segments (Fig. 5) ring- like, subequal in width, the first 4 times as wide as long, the second 3 times as wide as long and twice as long as the first, the third twice as wide as long and twice as long as the second; club longer than in female, 11-14 times as long as wide, 1 5 times as long as funicle, bearing about 20 longitudinal sensilla. Mesoscutum and scutellum each bearing 7-9 setae. Eighth sternum (Fig. 26) broadly crescent- shaped and rounded posteriorly, 3 times as wide as long at midline, about 1 .2 times as wide as seventh sternum. Genitalia (Fig. 26) 1/2 - 2/3 length of middle tibia, ventral surface of phallobase with distinct longitudinal thickening at midline, run- ning from between bases of digiti almost to apex, digitus with apical denticle about 1/3 its length, medial denticles slightly curved and 1/3 - 1/2 length of digitus (excluding apical denticle), phallobase sclerotized at base of medial denticles Volume 1, Number 1, 1992 245 Figs. 8-12. Chartocerus subaeneus. 8, Female head, pronotum, mesoscutum and scutellum (SEM). 9, Female mesosoma and base of metasoma. 10, Female propodeum and base of metasoma (SEM). 11, Male, apex of metasoma and genitalia, ventral aspect. 12, Female mesosoma and metasoma, sowing second phragma and ovipositor. 246 Journal of Hymenoptera Research Figs. 13-17. Chartocerus subaeneus, female: 13, Fore wing. 14, Hind wing. 15, Calcarand strigilon fore leg (SEM). 16, Middle leg. 17, Mid-tibial spur (SEM). and bearing a pair of lateral setae, slightly longer than medial denticles. Our material agrees well with the Fig. of Domenichini (1955), but the medial and apical denticles are somewhat longer relative to the digiti in our specimens. Material examined. — Redescribed from 20 fe- males and 1 3 males, reared in laboratory culture on Tetracnemoidea peregrina in the long-tailed mealy- bug, Pseudococcus longispinus, on potato sprouts, Rehovot, Israel. Types. — Lectotype male (present designation). "17/610, Frst, Plastocharis subaeneus Frt., Zool. Mus. Berlin." Mounted on a pinned card between small pieces of glass cemented across an opening. The mountant has partially dried out and the specimen is crushed and flattened but otherwise in reasonably good condition. One fore wing and the head are dissected and only the antennal scapes and a single club remain. This specimen is here designated lectotype and has been labelled accord- ingly. It is in the Museum fur Naturkunde der Humboldt Universitat zu Berlin. Paralectotype. "17/584, Aachen, Frst, Plastocharis subaeneus Frst, Zool. Mus. Berlin." Mounted in a manner similar to the lectotype but the mountant is more badly dried out. Foerster (1878) stated that this species was described from male and female material; however, as Novitzky (1954) pointed out, this specimen is a male Thysanus, probably ater Haliday . Also housed in the Museum fur Naturkunde. DEVELOPMENTAL STAGES Mummies of the long-tailed mealybug con- taining advanced larvae or pupae of T. peregrina were exposed to females of C. subaeneus for 24 hours, and were then kept at 32°C. At daily intervals, 30 mummies were dissected in saline solution under Volume 1, Number 1, 1992 247 20 %*~A p"«J 1 - Figs. 18-24. Chartocerus subaeneus, developmental stages. 18, Egg, several hours after oviposition. 19, Egg, one day after oviposition. 20, First instar larva. 21, Second instar larva, showing the cephalic skeleton and respiratory system. 22, Second instar larva, showing the oesophagus, midgut and salivary gland. 23, Second instar larva: spiracles. 24, Third instar larva. a stereoscopic microscope. Eggs and first-instar larvae were mounted directly in Hoyer's medium. Later developmental stages were soaked in chloro- phenol solution for 2-7 days prior to mounting in Hoyer's medium. For observation of respiratory systems, live larvae were immersed in bromo- phenol solution on a slide, covered with a cover slip and studied immediately under a phase-con- trast microscope. The egg (Figs. 18, 19) is hymenopteriform, ba- nana-shaped, with an elongate projection (or short stalk), grayish white, 265-300 u long, and 75-110 u wide. During the first few hours its contents appear as a mottled mass surrounded by a membrane, then the mouthparts and midgut become visible. The larva (Figs. 20-24) develops through 4 in- stars. These are distinguishable by their general dimensions and by the shape and size of their mandibles. All instars are hymenopteriform, with the head and 13 body segments evident, and all have 4 pairs of spiracles - in the mesothorax and first 3 abdominal segments (Fig. 23). First instar larva (Fig. 20) transparent white, elongate, taper- ing posteriorly, 215-260 u long and 60-75 u wide; mandibular denticle somewhat curved, 4 u long. Second instar (Figs. 21-23) of typical chalcidoid form, with the head partially withdrawn into the thorax, 325-480 u long and 125-200 u wide; man- dibles beak-like, 6 u long, with a broader base than in the first instar. The oesophagus, midgut and salivary gland are clearly evident at this stage (Fig. 22), as are the cephalic skeleton and respiratory system (Figs. 21, 23). The latter, as in the first instar, consists of two lateral longitudinal trunks, con- nected by transverse commissures in the prothorax and eighth abdominal segment; the mesothoracic 248 Journal of Hymenoptera Research Figs. 25-28. Chartocerus subaeneus. 25, Female metasoma: 17, T8 and epiproct. 26, Male genitalia and eighth sternum. 27, Fourth instar larva: cephalic skeleton. CSD = common salivary duct; E = epistoma; ES = oesophagus; H = hypostoma; HS = hypostomal spur; IPR = inferior pleurostomal ramus; M = mandible; MA = mandibular acron; MC = mandibular condyle; SPR = superior pleurostomal ramus; T = tentorium (terminology after Vance and Smith 1933). 28, Female pupa, ventral view. spiracles are larger than the other pairs. The mid- gut occupies the first 7 abdominal segments; the beginning of a hind-intestinal invagination can also be discerned. Third instar (Fig. 24) 800-900 \i long and 370-450 \i wide; mandibular denticle 10 n long. The midgut now occupies most of the body cavity, and the hind gut is clearly evident but still disconnected. Respiratory system as in the pre- ceding instars. A pair of large glands can be seen in the prothoracic region. Fourth instar 1000 u long and 450 |i wide; mandibular denticle 14-16 |i long. It is otherwise similar to the preceding instar. The cephalic skeleton is best seen in cleared specimens of this instar (Fig. 27). At the end of the fourth instar, the larva emits meconial pellets. The prepupa is milky white, somewhat smaller than the full-grown fourth instar. At 32°C, pupation takes place on the 7th day after oviposition. The pupa (Fig. 28) is of typical chalcidoid form. On the first day it is entirely pale, sometimes with beginnings of pigmentation on the vertex. On the second day pigmentation appears on the abdo- men, and the propodeal triangle becomes evident. On the third day pigmentation spreads to all parts of the body, and all imaginal organs can be dis- cerned. On the fourth day the pupa is entirely black. Adult emergence occurs 6 or 7 days after pupation. BIOLOGY Chartocerus subaeneus is a direct hyperparasite, attacking only parasitized, mummified mealybugs. It develops ectoparasitically upon well-developed larvae or pupae of its primary hosts within the mummified mealybug. Although occasional mummies were found to contain two Chartocerus eggs, development is always solitary and only one adult hyperparasite emerges from each secondary host. Prior to parasitization, the female usually host-feeds on its primary hosts. Reproduction is deuterotokous: virgin females give rise to female progeny, and males are rather rare. Random sam- pling of lab cultures yielded 5.25% males. However, males were observed to court females and tried to mate with them. Volume 1, Number 1, 1992 249 Adult Behavior: Predatory Host-Feeding and Oviposition Female C. subaeneus wasps are positively pho- totactic, negatively geotactic, and positively thigmotactic, tending to enter crevices, folded leaves, mealybug egg masses and empty mum- mies. Upon encountering a mummified mealybug, the female wasp walks around and over it and taps it with the tips of her antennal clubs. Some hosts are accepted rapidly (1-2 min.), but for others more prolonged examination is needed before a decision to accept or reject the host is reached. When a mummy is found acceptable, the wasp turns around, with her caudal end directed towards it, and examines it with her ovipositor. If all is well, this again may take only 2 minutes or less; other- wise, the examination is prolonged until the host is accepted or rejected. When the site of attack is selected, the wasp appears to lean with her antennae upon the substrate, her body pressed hard to the mummy, and starts drilling a host-feeding hole. During drilling, the entire body is seen to tremble, and the ovipositor may be partly withdrawn and re-inserted. An inexperienced wasp may drill for 12-23 min., whereas wasps with several days' ex- perience accomplish the task in 10-14 min. After the ovipositor is withdrawn, the wasp examines the mummy for a few seconds with her antennae, locates the hole, and commences feeding. Immedi- ately after feeding is completed, the wasp turns around and drills again in the same area, searches with her ovipositor inside the mummy, and lays an egg. Drilling and oviposition take 8-13 min., after which the wasp moves on to another mummy, examines it with her antennae and ovipositor, drills and oviposits in it without further host-feeding. In two hours a wasp may construct a feeding hole, host-feed, and lay about 3 eggs in as many mum- mies. Most wasps went through this cycle of host- feeding and oviposition. However, a few departed from it and laid an egg before host-feeding or, when offered honey, fed upon it before laying an egg- For successful drilling by C. subaeneus, the sec- ondary host mummy has to be secured to the substrate. In nature, parasitized mealybugs tend to hide in crevices and adhere to the substrate prior to mummification. Two types of host-feeding were observed: a short feeding period of 1-4 min., and a longer one lasting 12.5 - 22 min. Both were always followed by oviposition upon the same host. It appears that the short host-feeding period serves mostly as a stimulant to oviposition, whereas the longer period serves to satisfy the wasp's nutritional requirements for continued oviposition. Extensive feeding may result in death of the primary host. Indeed, some of the mealybug mummies in our C. subaeneus cultures did not yield any parasite, primary or secondary, and comparison with mummies exposed to T. peregrina alone indicated that the incidence of such mortality was significantly higher in the presence of the hyperparasite than in its absence (19.1% vs. 7.3%, respectively, p=0.05). Host Range In single-choice laboratory experiments, females of C. subaeneus readily examined, host-fed and oviposited upon the following encyrtid primary hosts, on which their progeny developed to ma- turity: Anagyrus fusciventris (Girault), Anagyrus pseudococci (Girault), Leptomastidea rubra Tachikawa and Tetracnemoidea peregrina (Compere) in the long- tailed mealybug, Pseudococcus longispinus (Targioni Tozzetti); Anagyrus pseudococci (Girault), Clausenia josefi Rosen and Leptomastix dactylopii Howard in the grape mealybug, Planococcus vitis (Niedielski); Anagyrus pseudococci (Girault) in the citrus mealy- bug, Planococcus citri (Risso); and Clausenia purpurea Ishii in the citriculus mealybug, Pseudococcus citriculus Green. The wasps examined, inserted their ovipositor into and host-fed upon the encyrtid Microterys flavus (Howard) in the brown soft scale, Coccus hesperidum L. (Homoptera: Coccidae), and Aphidius sp. (Hymenoptera: Aphidiidae) in mummies of the oleander aphid, Aphis nerii Boyer de Fonscolombe (Homoptera: Aphididae), but no eggs were laid upon these hosts. Puparia of Drosophila melanogaster were ignored by the wasps. Fecundity Materials and methods. — In order to determine whether the wasps were pro- or syno vigenic, several newly-emerged females were dissected before they had the chance to either feed or oviposit, and their ovaries were examined. Cards bearing 20-30 mummies of the long-tailed mealybug, containing T. peregrina, were placed in small plastic cups. A silk cover was fastened to the cup by means of a plastic lid in which a large hole was bored for ventilation, and some honey was Journal of Hymenoptera Research 16 20 DAYS Fig. 29. Chartocerus subaeneus, daily progeny production at 28°C, >50% RH (initial n = 6). streaked on the inside of the cup. Six newly-emerged female wasps were placed singly in these oviposi- tion cups, at 28+1 °C, >50% RH and a photoperiod of 12LT2D, and were transferred to new cups, without anaesthetization, at daily intervals throughout their life. Following oviposition, the cups were kept at 28±1°C, and emergence of C. subaeneus progeny was recorded daily. Results. — Dissection of 10 newly-emerged fe- males revealed that each ovary comprised 4 ovari- oles, each containing one fully-developed egg. Oviposition commenced upon the day of emergence and continued evenly throughout the female's life span, declining somewhat in the last days (Figs. 29, 30) . On average, a female laid 57% of her eggs during the first half of her life. Fecundity was rather high. The females lived for a mean of 24.9 days (17-30), and oviposited DAYS Fig. 31 . Chartocerus subaeneus, effect of photoperiod on survival of adult females at 28°C, >50% RH, with honey as food. 80 1 1 1 1 1 1 1 1 160 JJ 40 P Ill 170 _ —i < > LU Lu 100 — / ~ rr LU a. 80 J - > in 60 — / - o o ir Q_ 40 20 P 1 I 1 I 1 1 1 1 12 16 20 DAYS 24 28 32 Fig. 30. Chartocerus subaeneus, cumulative progeny production at 28°C, >50% RH (initial n = 6). throughout that period (average 24.3 days). Daily progeny production averaged 6.8, and mean total fecundity was 163.3 progeny per female (range 125-192). FACTORS AFFECTING ADULT LONGEVITY Photoperiod Materials and methods. — Batches of 15 or more newly-emerged female wasps were kept in small plastic cups (as in Fecundity, above), with some honey as food, at 28±1 °C and >50% RH, under 24D, 12LT2D and 24L. Mortality was recorded daily. Results. — As shown in Fig. 31, the longevity of adult females was similar at 12LT2D and 24L, but their longevity was prolonged considerably at 24D. This may have resulted from reduced activity in darkness. Relative humidity Materials and methods. — To assess the moisture requirements of C. subaeneus, the longevity of fe- male wasps was compared under 0% and 50% RH, as suggested by Bartlett (1962). Two small plastic cups, each with a silk cover held in place by a plastic lid with a large hole in it, were sealed and fastened to one another, lid to lid, with Permagum " cords (Virginia Chemicals, U.S.A.) so that they Volume 1 , Number 1 , 1 992 251 0.08 100 I I I 1 1 l I 80 - 3 ~60 \o "/. \ 50 •/. >40 in 20 1 4 ' 1 1 1 1 DAYS 10 12 14 16 18 20 22 24 26 28 X= TEMPERATURE (°C) Fig. 32. Chartocerus subaeneus, effect of relative humidity on survival of adult females (black circle n = 47; open circle n = 45). formed a closed unit. Relative humidity was con- trolled by placing in the bottom cup dry P.O. for 0% RH or a solution of 62.5 gr KOH in 100 cc water for 50% RH (Peterson 1 964). Some honey was streaked in the upper cup, and after the system was allowed to reach an equilibrium for 48 hours at 28±1°C, it was opened momentarily and several newly- emerged female wasps were placed in the upper cup. Forty-seven wasps were used at 0% RH, 45 at 50% RH. The units were kept in the dark, at 28+1 °C, and mortality was recorded daily. Results. — C. subaeneus is rather susceptible to low relative humidity (Fig. 32). At 0% RH, 50% mortality was reached on the third day and the last survivors died on the fourth day; whereas at 50% RH, 50%> mortality was reached on the 12th day and the last survivors died on the 16th day. Nutrition When batches of 10 or more newly-emerged female wasps were kept at 28±1°C and >50% RH, with no food or water and in the absence of hosts, they all died within 3 days. Provision of water for drinking did not prolong their life span. Provision of pollen in addition to honey, at 1 2L: 1 2D and in the absence of hosts, shortened the longevity of the wasps considerably in comparison to that on honey alone: 50% mortality was reached on the 4th day, and the last survivors died on the 6th day (compare with Fig. 31, 12L:12D for survival on honey alone). In all the experiments with honey in the absence of hosts, the longevity of adult female wasps was Fig. 33. Chartocerus subaeneus, effect of temperature on rate and duration of development. considerably lower than in the presence of hosts. The 6 females used in the fecundity experiment (Fig. 29) had a mean life span of 24.9 days, whereas under similar conditions but without hosts their mean life span was 6.9 days and they never sur- vived for more than 16 days (see Figs. 31, 32). Predatory host-feeding must have a pronounced effect in prolonging the life span of C. subaeneus. Effect of Temperature on Rate of Development Materials and methods. — Cards bearing long- tailed mealybug mummies, containing T. peregrina, were exposed to females of C. subaeneus for 24 hours at room temperature, and were then placed in incubators at 24°, 25°, 28° and 32°C. Emergence of adult C. subaeneus progeny was recorded daily. The equilateral hyperbola equation, based on the assumption that the product of developmental time and temperature above a certain threshold is a constant for any given species, is a convenient way of expressing the effects of temperature on the duration of development of insects (Bodenheimer Table 1 . Effect of temperature on duration of development of C. subaeneus. Temperature Duration of development (days) (°C) N Range Average ± SD 24 25 28 32 11 34 52 43 23-25 18-27 15-19 12-14 23.92 ± 0.67 21.77 ±2.30 16.39 ±0.71 12.86 ±0.64 252 Journal of Hymenoptera Research 1958). The hyperbola equation for C. subaeneus was calculated as follows: rates of development at the various constant temperatures tested were obtained as the reciprocals of the developmental periods; the linear regression (y = a + bx) of developmental rate on temperature was then calculated by the method of least squares; the parameters of the equilateral hyperbola (thermal constant, ThC, and the developmental threshold, c), were then ob- tained from the identities ThC = 1/b; c = a/b. Results. — The results are presented in Table 1. The regression of the rate of development on temperature and the corresponding equilateral hyperbola for C. subaeneus are presented in Fig. 33. The calculated developmental threshold was 1 4.8°C and the thermal constant was 221 .52 days-degrees. Since C. subaeneus developed normally at 32°C, the upper temperature threshold must have been rather high. DISCUSSION The oviposition behavior of C. subaeneus is similar to that of other Signiphoridae. Other spe- cies have been observed to require lengthy periods for oviposition (Woolley and Vet 1981, Agekyan 1968, DeBach et al. 1958, Clausen 1924), and other species appear to require a period of host-feeding before oviposition can occur (see Woolley and Vet 1981, Quezada et al. 1973). Oviposition upon the same individual hosts which were used for host- feeding was observed in all of these cases, and in C. subaeneus it is the most common behavioral se- quence. The biology of only one other species of Chartocerus, C. elongatus, has been reported in any detail (Clausen 1924). Like this closely-related spe- cies, C. subaeneus is an obligate hyperparasite. In fact, we know of no cases (published or unpub- lished) in which it is clear that a Chartocerus species develops as a primary parasite. This is in contrast to Signiphora, in which some species are primary and others are hyperparasitic. In our experiments, C. subaeneus was strictly a solitary parasite, but Clausen (1924) found C. elongatus to be gregarious in attacking primary parasites of Pseudococcus maritimus (Ehrhorn). The C. subaeneus female emerges with several well-developed eggs that she may deposit on the first day of her adult life, and develops the rest continually during her lifetime. Predatory host- feeding or other sources of proteinaceous nutrition are not required, other than as a stimulant for the beginning of oviposition, but are presumed to be necessary for continuous egg production in later stages. As has been reported for other ectophagous hyperparasites (Sullivan 1987), Chartocerus subaeneus appears to be rather polyphagous, ca- pable of attacking various encyrtid primary para- sites within various mummified mealybugs. It may utilize other primary parasites developing in yet other homopterous hosts for host-feeding. This may enhance its survivorship in the absence of suitable hosts for oviposition. We were intrigued to find that the egg of C. subaeneus bears an elongate projection similar to that reported for C. elongatus by Clausen (1924). Such a projection has not been reported for any Signiphora species to our knowledge, and it may have system- atic significance. ACKNOWLEDGMENTS We thank Dr. Frank Koch, Museum fur Naturkunde der Humboldt Universitat zu Berlin, for the loan of Foerster's type specimens. Prof. E. Swirski and Dr. M. Wysoki, the Volcani Center, Bet Dagan, Israel, provided biological material and helpful advice. LITERATURE CITED Agekyan, N.G. 1968. Signiphora merceti Malen. (Hymenoptera, Chalcidoidea) - a parasite of Hemiberlesia rapax (Comst.) in Adzharia. Entomological Review 47: 484-486. Bartlett, B.R. 1962. The ingestion of dry sugars by adult entomophagous insects and the use of this feeding habit for measuring the moisture needs of parasites. Journal of Economic Entomology 55: 749-753. Bodenheimer, F.S. 1958. Animal Ecology To-day. Monographiae Biologicae Volume VI, Dr. W. Junk, The Hague, 276 pp. Clausen, C.P. 1924. The parasites of Pseudococcus maritimus (Ehrhorn) in California. Part II. Biological studies and life histories. University of California Publications in Entomology 3: 253-288. DeBach, P., C.E. Kennett and R.J. Pence. 1958. Species of Thysanus as primary parasites, journal of Economic Entomology 51: 114-115. Domenichini, G. 1 955. Variability dei caratteri e nuova diagnosi di un Tisanide (Hym. Chalcidoidea) con la descrizione di una nuova specie. Annali delta Facolta di Agraria (Nuova Serie), 4: 25-42. Hayat, M. 1970. Studies on the genera of the family Signiphoridae (Hymenoptera: Chalcidoidea) recorded from India. Entomophaga 15: 387-399. Hayat, M. 1976. Some Indian species of Chartocerus (Hym.: Chalcidoidea: Signiphoridae). Oriental Insects 10: 161-164. Novitzky, S. 1954. Sinonimia e distribuzione di Signiphorina subaenea Forst (Hym., Chalo, Thysanidae), iperparassita dei Coccidi (Pseudococcus sp.). Bollettino di Zoologia Agraria e Bachicoltura 20: 203-213. Volume 1, Number 1, 1992 253 Peterson, A. 1964. Entomological Techniques, 10th Edition. Entomological Reprints, Los Angeles, 435 pp. Quezada, J.R., P. DeBach and D. Rosen. 1973. Biological and taxonomic studies of Signiphora borinquensis, new species, (Hymenoptera: Signiphoridae), a primary parasite of diaspine scales. Hilgardia 41: 543-604. Rosen, D.,ed. 1981. The Role of Hyperparasitismin Biological Control: a Symposium. University of California, Division of Agricultural Sciences, Publication 4103, 52 pp. Rozanov, L.V. 1965. Review of the Genera of parasitic Hymenoptera of the family Signiphoridae (Hymenoptera, Chalcidoidea). Entomological Review 44: 508-515. Sullivan, D.J. 1987. Insect hyperparasitism. Annual Review of Entomology 32: 49-70. Swirski, E., Y. Izhar, M. Wysoki, E. Gurevitz and S. Greenberg. 1980. Biological control of the longtailed mealybug Pseudococcus longispinus (Coccoidea, Pseudococcidae) in the avocado plantations of Israel. Entomophaga 25: 41 5-426. Swirski, E.and M. Wysoki. 1988. Integrated pest management in the avocado orchards of Israel. Applied Agricultural Research 3: 1-7. Vance, A.M. and H.D. Smith. 1933. The larval head of parasitic Hymenoptera and nomenclature of its parts. Annals of the Entomological Society of America 26: 86-94. Viggiani, G. 1990. Hyperparasites. Chapter 2.5, pp. 177- 181. In Rosen, D., ed. Armored Scale Insects: Their Biology, Natural Enemies and Control. World Crop Pests Volume 4B, Elsevier Science Publishers, Amsterdam. Woolley, J.B. 1988. Phylogeny and classification of the Signiphoridae (Hymenoptera: Chalcidoidea). Systematic Entomology 13:465-501. Woolley, J.B. 1990. Signiphoridae. Chapter 2.4.3, pp. 167-176. In Rosen, D., ed. Armored Scale Insects: Their Biology, Natural Enemies and Control. World Crop Pests Volume 4B, Elsevier Science Publishers, Amsterdam. Woolley, J.B. and L.E.M. Vet. 1981. Postovipositional web- spinning behavior in a hy perparasite, Signiphora coquilletti Ashmead (Hymenoptera: Signiphoridae). Netherlands Journal of Zoology 31: 627-633. A Review of the Genus Hingstoniola (Hymenoptera: Sphecidae: Crabronini) J. HYM. RES. 1(1), 1992 pp. 255-260 WOJCIECH J. PULAWSKI AND HELEN K. COURT California Academy of Sciences, Golden Gate Park, San Francisco, California 941 18, U.S.A. Abstract. — Niwoh Tsuneki, 1984, is synonymized with Hingstoniola Turner and Waterston, 1926, and Nhvoh tarsata Tsuneki, 1984, is transferred to the latter genus. An updated generic description of Hingstoniola is provided and differences from related genera are discussed. A section containing Hingstoniola in Bohart and Menke's key to Crabronini is revised. A key to males of the three included species is provided. Hingstoniola pagdeni is first recorded from Thailand. Hingstoniola is a little-known genus of crabronine wasps, endemic to the Oriental Region. It was established by Turner and Waterston (1926) as a subgenus of Crabro for their new species duplicate! from Sikkim, northern India. Pagden (1934) de- scribed a second species, fimbriata (nee Rossi, 1790), from Malaysia. Pate (1944) raised Hingstoniola to genus and suggested it was a member of his Foxita complex. Leclercq included it in his keys to the genera of Crabroninae (1951, 1954) and described the first female (1963). Court in Bohart and Menke (1976:417) partially redescribed the genus and summarized the available information. Most of these treatments are either incomplete or contain factual errors. In 1984a, Tsuneki described a new genus Niwoh, which is clearly a synonym of Hingstoniola. This paper is an attempt to correct inaccuracies and omissions and to present an up- dated review of the genus. The following abbreviations are used for insti- tutions in which the material is housed: BMNH: British Museum (Natural History), London, En- gland (now The Natural History Museum); CAS: California Academy of Sciences, San Francisco, California, USA; USNM: United States National Museum of Natural History (= Smithsonian Insti- tution), Washington, D.C., USA. Genus HINGSTONIOLA Turner and Waterston Hingstoniola Turner and Waterston, 1926: 189 (as a subgenus of Crabro). Type species: Crabro duplicatus Turner and Waterston, 1926:190, by monotypy. Niwoh Tsuneki, 1984a:20. Type species: Niwoh tarsatus Tsuneki, 1984a: 20, by monotypy. Gender: masculine ("Deva King, guardian giant bonze of Budda"). New synonymy. Synonymy. — An analysis of the original de- scription of Nhvoh and a subsequent study of the type species of Hingstoniola and Nhvoh convinced us that these two nominal genera are synonyms. Diagnosis. — Hingstoniola is distinguished from other crabronines by the following combination of characters: scapal basin margined dorsally and laterally by a well-defined carina (Fig. 2) and bi- sected by a vertical carina in males and some females; median lobe of clypeus double-edged (Fig. 1), area between edges concave and delimited lat- erally by a longitudinal carina on each side; head and thorax with coarse, irregularly reticulating ridges, interspaces microareolate (Fig. 3), hence dull; frons with neither carina nor furrow between midocellus and scapal basin (Fig. 3); and males with flagellum fimbriate anteriorly (Fig. 2), foretarsus conspicuously expanded, and midtibia lacking apical spur. Description. — Head and thorax with coarse, ir- regularly reticulating ridges superimposed on microareolate interspaces (Fig. 3); eyes asetose, inner orbits converging below; scapal basin bor- dered both dorsally and laterally by a well-defined carina (Fig. 2), bisected by vertical carina in males (Fig. 2) and some, but not all, females (Tsuneki, 1984a:24); frons with neither carina nor furrow between midocellus and transverse carina delimit- ing scapal basin (Fig. 3); orbital foveae present (Fig. 3); ocellar triangle slightly broader than high (Fig. 3); postocular sulcus present, foveolate, delimited by carina, or absent; gena simple; occipital carina flanged, foveate, joining or ending just short of hypostomal carina; antennal sockets contiguous to each other, contiguous to or separated from orbit; scape bicarinate, carina well defined from base to 256 Journal of Hymenoptera Research apex; male flagellum with 11 articles, modified, with anterior rather than ventral fringe of fimbriae (Fig. 2) (flagellum fimbriate in pagdeni and tarsata, and row of long, appressed setae on the flagellum of the holotype of duplicata apparently originally erect); flagellomeres I-X with raised, carina-like structure that has median, longitudinal slit (Figs. 4 and 5); slit bottom with micropores (we observed a carina on flagellomeres VI-X in dupilicntn, but could not study its microstructure); median lobe of clypeus double-edged (Fig. 1), area between edges concave and delimited laterally by a longitudinal carina on each side; palpal formula 6 + 4; mandibular apex tridentate in female (Fig. 1 ), bidentate in male; externoventral (= posterior) margin entire, inner margin with tooth on basal half; pronotal collar carinate anteriorly, notched medially, angulate laterally; scutum without anterolateral transverse carinae; notauli and admedian lines present or obscured by coarse sculpture; prescutellar sulcus well developed and foveate; axillae moderately broadened; scutellum margined laterally and posteriorly; metanotum coarsely sculptured; mesopleuron with postspiracular carina, omaulus and acetabular carina continuous; verticaulus present; sternaulus, hypersternaulus, and mesopleuraulus absent; propodeum coarsely sculptured, enclosure areolate; lateral propodeal carina well developed; male legs with fore- and midtarsi modified, forefemoral venter with longi- tudinal carina; midtibial spur present in female, absent in male; recurrent vein joining submarginal cell beyond middle of cell's hindmargin; jugal lobe slightly longer than submedian cell (appears shorter in some specimens); gaster sessile; pygidial plate narrow, concave in female, absent in male. Systematics. — A study of cladistic relationships of Hingstonioln to other Crabronini is beyond the scope of the present paper. Instead, comparisons are made between Hingstonioln and other genera in which the scapal basin is delimited by a carina both dorsally and laterally. This conspicuous feature, found only in Enoplolindenius (New World), Foxita (Neotropical), Hingstonioln, and Vechtia (Oriental), is clearly derived within the Sphecidae and may be a synapomorphy of these genera. The goal is to facilitate recognition of Hingstonioln and to review the distribution of taxonomically important char- acters. Unlike Hingstonioln, the scapal basin in the other three genera is not bisected by a vertical carina; the clypeal margin is single-edged; the head and tho- rax are shiny, not reticulate (head matte in Foxitn leydensis Leclercq); the frons has a carina between the anterior ocellus and the scapal basin (reduced in Foxitn cnstricn Leclercq); and the male flagellum is not fimbriate anteriorly but has a ventral setal fringe in some Enoplolindenius and some Foxitn. The male foretarsus is conspicuously expanded in Hingstonioln and some Enoplolindenius, simple in the other two genera. Hingstonioln, Foxitn, and Vechtin differ from Enoplolindenius in having the mandible tridentate in the female and bidentate in the male, palpal formula 6 + 4, scutum without anterior transverse carinae, and female pygidial plate narrow, concave. Enoplolindenius has the mandibular apex simple; palpal formula 6 + 3; scutum with a distinctive carina that extends outwards from each notaulus parallel to the scutal foremargin; female pygidial plate broad, flat; and male midtibial spur present or absent. Hingstonioln is further separated from Foxitn in having the following: the occipital carina does not form a complete circle, but joins the hypostomal carina or nearly so; and the hypersternaulus, mesopleuraulus, and male midtibial spur are ab- sent. In most Foxitn (in part from Leclercq, 1980), the occipital carina forms a complete circle separated from the hypostomal carina (evanescent mesoventrally in females of beieri Leclercq, gnlibi Pate, and nnbeieri Leclercq, and subtangent to the apex of V-shaped hypostomal carina in ntorni Pate species group), the hypersternaulus and mesopleuraulus are present or absent, and the male midtibial spur is present. In addition, the recurrent vein joins the submarginal cell beyond the midlength of the cell's hindmargin in Hingstonioln, before to beyond middle in Foxitn (not always near middle as stated by Court). Hingstonioln differs from Vechtin in having the following; the carina that borders the scapal basin dorsally is not lamellate, the occipital carina joins the hypostomal carina or nearly so, the sternaulus is absent, and the recurrent vein joins the sub- marginal cell beyond the middle of the cell's hindmargin. In Vechtin, the scapal basin carina is expanded dorsally into a triangular, downcurved lamella, the occipital carina forms a complete circle separated from the hypostomal carina, the sternaulus is present, and the recurrent vein joins the submarginal cell at or near the middle of the Volume 1, Number 1, 1992 257 cell's hindmargin. The male midtibial spur is ab- sent in Vechtia rugosa (F. Smith), but present in V. prerugosa Leclercq (holotype examined). The following replaces couplets 1 0- 1 2 in the key to genera of Crabronini by Bohart and Menke, 1976: 374. The figure numbers refer to the illus- trations in their book. Three species are currently included in Hingstoniola: duplicata (Turner and Waterston) pagdeni Leclerq, and tarsata (Tsuneki). The fe- male of duplicata is unknown and that of tarsata is not available for study. The differ- ences between the males are summarized in the second key below. KEY TO GENERA OF CRABRONINI WITH DORSALLY AND LATERALLY MARGINED SCAPAL BASIN 10. Scutum with transverse anterolateral carinae (fig. 121 H); mandibular apex simple; female pygidial plate broad, flat, coarsely punctate; New World Enoplolindenius Rohwer — Scutum without transverse anterolateral carinae; mandibular apex tridentate in female, bidentate in male; female pygidial plate markedly narrowed, concave H 11. Dorsal carina of scapal basin expanded medially into a downcurved, triangular lamella (fig. 122 1); sternaulus present; Oriental Vechtia Pate — Dorsal carina of scapal basin nonlamellate medially; sternaulus absent 12 12. Head and thorax with coarse, reticulate sculpture; occipital carina not a complete circle, joining hypostomal carina or ending just short of it (hypostomal carina U-shaped); median clypeal lobe double-edged, area between edges concave and delimited laterally by longitudinal carina on each side; male flagellum with anterior fringe of fimbriae; male foretarsus conspicuously expanded; Oriental Hingstoniola Turner and Waterston — Head and thorax without reticulate sculpture; occipital carina a complete circle (evanescent mesoventrally in some females), well separated from hypostomal carina (if latter U-shaped) or subtangent to it (if V-shaped); median clypeal lobe single-edged; male flagellum without anterior fringe of fimbriae; male foretarsus simple; Neotropical Foxita Pate KEY TO MALES OF HINGSTONIOLA Median clypeal carina expanding to form a raised, blunt tooth that extends beyond clypeal margin; flagellomere XI with no basal tubercle; metanotum undivided mesally; forefemoral venter angulate at basal one-third of length, angle with cluster of erect setae; foretarsomeres I— 1 1 1 without well-defined color pattern, each with one long seta at anterodistal angle (= side away from articulation of tarsomere 11); foretarsomere 1 acutely angulate anterodistally duplicata (Turner and Waterston) Median clypeal carina not expanding into median projection (free margin of clypeal lobe truncate mesally); flagellomere XI with sharp tubercle basoventrally (Fig. 2); metanotum anteromedially with lunate, sharply margined area; forefemoral venter with a few stiff, erect, sparsely spaced setae, not angulate at basal one-third; foretarsomeres 1-I1I with conspicuous black pattern, anterior margins (= side away from tarsal articulations) with long, curved fimbriae except basally; foretarsomere I rounded anterodistally 2 Anterior margin of foretarsomere I about 1.3 x posterior margin; midlengths of midtarsomere II and midtarsomere III equal to their respective apical widths tarsata (Tsuneki) Anterior and posterior margins of foretarsomere I about equal in length; midlength of midtarsomere II 0.9 x apical width, of midtarsomere III 0.6 x apical width pagdeni Leclercq DISCUSSION OF SPECIES Hingstoniola duplicata (Turner and Waterston) Crabro duplicata Turner and Waterston, 1926:190, male, incorrect original termination. Holotype: male, India: Sikkim: Kalimpong, 1 220 m, 27 Mar 1 924, R. W.G. Hingston collector (BMNH), examined. — Pagden, 1934:482 (comparison with Crabro fimbriatus). — As Hingstoniola duplicata: Pate, 1944:377 (new combination); Leclercq, 1951:52 (type examined), 1954: 218 (listed); Bohart and Menke, 1976: 417 (listed). This distinctive species is known only from the holotype male, which is in poor condition. The labiomaxillary complex and right antenna are missing, and the apical two flagellomeres of the remaining antenna are disjointed. Apparently as a result of improper preservation, the eye surface is irregularly ridged, the ocelli are collapsed (alveo- late in appearance), the wings are dirty, and many setae, including those on the antenna, are appressed 258 Journal of Hymenoptera Research Figs. 1-5. Hingstoniola pagdeni Leclercq. 1 , Female clypeus obliquely from below (x 60), with arrows showing the upper and lower clypeal edges. 2, Male head and antenna obliquely from the side (\ 47), with arrow showing tubercle on flagellomere XI. 3, Male frons in top view (x 79). 4, Flagellomeres VI, VII, and part of VIII (x 470). 5, Slit of flagellomere VII (x 3350). Volume 1, Number 1, 1992 259 to the integument. Fortunately, males of duplicata are easily distinguished from those of pagdeni and tarsata by the characters given in the key. Females will probably be most readily recognized by the undivided metanotum. Turner and Waterston (1926) incorrectly de- scribed the forefemur of the male duplicata as having a ventral spine at one third of its length. In reality, the femur is angulate, with a cluster of erect setae at the angle. Pagden (1934) thought that duplicata differed from pagdeni in lacking the row of erect fimbriae on the flagellum, but the fimbrial row in the type is probably merely matted down. Hingstoniola pagdeni Leclercq Crabro fimbriata Pagden, 1934:482, male, incorrect original termination. Holotype: male, Malaysia: Kedah: Bukit Panchor, 4 June 1930, H.T. Pagden collector (BMNH), examined. Nee Crabro fimbriatus Rossi, 1790. — Pagden, 1934:476 (as prey of Cerceris kngkasukae). — In Hingstoniola: Leclercq, 1951:52 (new combination, listed). Hingstoniola pagdeni Leclercq, 1954:21 8, replacement name for Crabro fimbriata Pagden. — Leclercq, 1963:47 (Malaysia: Kuala Lumpur; description of female); Bohart and Menke, 1976: 418 (listed). Crabro paruiornatus Cameron: Leclercq, 1951:52, nomen nudum (Borneo: Kuching). The holotype of pagdeni is also in poor condi- tion: it lacks the flagella and gaster. The head is missing in the male labeled asparviornatus Cameron (the only specimen studied by Court in Bohart and Menke, 1976). This species is very similar to tarsata (see the latter for discussion). The holotype of pagdeni was col- lected as prey of a Cerceris that Pagden described as langkasukne on p. 476, but called spiniventris, a no- men nudum, in the holotype data of pagdeni on p. 486 (Krombein, 1981:30, synonymized langkasukae with bidentula Maidl, 1926). Pagden himself re- ported that this was an unusual prey record since the other females were taken with buprestids, the normal prey of this species. Hingstoniola pagdeni was described from Bukit Panchor, Kedah Province, Malaysia, and subse- quently recorded from Kuching, Borneo (Leclercq, 1 951 ) and Kuala Lumpur, Malaysia (Leclercq, 1 963) . An additional, northernmost locality is Doi Suthep mountain in Chiang Mai Province, Thailand (4 females, 3 males, 1-2 May 1989, W.J. Pulawski collector, CAS). These specimens were flying around bushes in the sun in a little stream valley not far from the Wat Phra That temple. Hingstoniola tarsata (Tsuneki), new combination Niwoh tarsata Tsuneki, 1984a:20, male, female, incorrect original termination (correctly spelled tarsatus on p. 25). Holotype: male, Philippines: Mindanao: Cagayan de Oro: Makahambus Cave, 15 Aug 1980, T. Murota collector (originally K. Tsuneki collection, now USNM), examined. — As Niwoh tarsatus: Tsuneki, 1984b: 2 (Philippines), 30 (in key). In addition to the characters given in the key, tarsata and pagdeni differ in the shape of the clypeus and the flagellar slits. The median clypeal carina is flattened apically to form a triangular bevel in tarsata, whereas pagdeni has no bevel. The width of a flagellar slit is about two fimbria diameters in tarsata and about one diameter in pagdeni (Figs. 4, 5). So far, tarsata is known only from Mindanao Island, Philippines. ACKNOWLEDGMENTS We sincerely thank the persons who helped in preparation of this paper. Arnold S. Menke (Systematic Entomology Laboratory, United States Department of Agriculture) and Karl V. Krombein (Smithsonian Institution) lent the holotype and a paratype of Niwoh tarsatus, respectively, and Colin R. Vardy (British Museum, Natural History) sent the holotypes of Hingstoniola duplicata and H. pagdeni. Arnold critically reviewed the manuscript, Vincent F. Lee proofread it, and Elizabeth L. Kimball helped with the English. Darrell Ubick commented about the style and took the scanning electron micrographs. The senior author's fieldwork in Thailand was supported by the National Science Foundation (Grant Number BSR-8722030). LITERATURE CITED Bohart, R.M., and A.S. Menke. 1976. Sphecid wasps of the world. A generic revision. University of California Press, Berkeley, Los Angeles, London, 1 color plate, IX + 695 pp. Krombein, K.V. 1981. Biosystematic studies on Ceylonese wasps, VIII: a monograph of the Philanthidae (Hymenoptera: Sphecoidea). Smithsonian Contributions to Zoology No. 343:1-111, 1-75. Leclercq, J. 1951. Notes systematiques sur quelques Crabroniens (Hymenoptera Sphecidae) americains, orientaux et australiens. Bulletin et Annates de la Societe Entomologique de Belgiquc 87: 31-56. Leclercq,!. 1954. Monographie systematique, phylogenetique et zoogeographique des Hymenopteres Crabroniens. Les Presses de , Liege, 371 pp., 84 maps. Leclercq, ]. 1963. Crabroniens d'Asie et des Philippines (Hymenoptera Sphecidae). Bulletin et Annates de la Societe Royale d'Entomologie de Belgique 99: 1-82. Leclercq, J. 1980. Crabroniens d'Amerique Latine appartenant aux genres que Vernon S.L. Pate nomma Chimila, Foxita et 260 Journal of Hymenoptera Research Taruma. Bulletin de In Societe Royale des Sciences de Liege 49: Tsuneki, K. 1984b. Studies on the Philippine Crabroninae, 70-83. revision and addition, with an annotated key to the species Pagden, H.T. 1934. Biological notes on some Malayan aculeate (Hymenoptera Sphecidae). Special Publications of the Japan Hymenoptera II. With descriptions of new species. Journal Hymenopterists Association 29: 1-50. of the Federated Malay States Museums 17: 467-492. Turner, R.E., and J. Waterston. 1926. On a new subgenus of Pate, V.S.L. 1944. Conspectus of the genera of pemphilidine Crabro. The Annals and Magazine of Natural History (9) 17: wasps (Hymenoptera: Sphecidae). The American Midland 189-191. Naturalist 31: 329-384. Tsuneki, K. 1984a. New material of sphecid wasps from the Philippines (Hymenoptera). Special Publications of the Japan Hymenopterists Association 28: 13-57. INSTRUCTIONS FOR AUTHORS The journal of Hymenoptera Research invites papers on all aspects of original research on the Hymenoptera. Subject matter may include biology, behavior, ecology, systematics, taxonomy, genetics, and morphology. Publication is available only to members of the International Society of Hymenopterists. At least one author of a multi- authored paper must be a member. Authors who are not members may apply for membership when they submit a paper for publication. All papers will be reviewed by at least two referees. The referees will be chosen by the appropriate subject editor. However, it would be helpful if authors would submit the names of two persons who are competent to review the manuscript. Acceptance of papers is based only on their scientific merit. The language of publication is English. Summaries in other languages are acceptable. Format and Preparation Manuscripts should be on letter size or A4 paper, double spaced, with at least 25 mm margins on all sides. 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If characters are run non- additively, this should be stated along with weighting criteria. A data matrix should be provided if the subject is complex. Cladograms must be hung with characters and these should include descriptors (not numbers alone) when feasible. If there are multiple equally parsimonious cladograms, the exact number should be stated, and reasons given for the one adopted. Lengths and consistency indices should be provided. Adequate discussions should be given for characters, plesiomorphic conditions, and distributions of characters among outgroups when problematical. References in the text should be (Smith 1999), without a comma, or Smith (1999). Two articles by a single author should be (Smith 1999a, 1999b) or Smith (1999a, 1999b). For papers in press, use "in press," not the expected publication date. The Literature Cited section should include all papers referred to in the paper. Journal names should be spelled out completely. Charges Publication is free to members of the International Society of Hymenopterists. At least one author of the paper must be a member. There are no free reprints. Reprints are charged to the author and must be ordered when returning the proofs. Author's corrections and changes in proof are also charged to the author. Color plates will be billed at full cost to the author. All manuscripts and correspondence should be sent to: David R. Smith, Editor Systematic Entomology Laboratory c/o U.S. National Museum NHB 168 Washington, D.C. 20560, U.S.A. CONTENTS (Continued from front cover) MENKE, A.S. Mole cricket hunters of the genus Larra in the New World (Hymenoptera: Sphecidae, Larrinae) . . 175 NORDEN, B.B., K.V. KROMBEIN, and B.N. DANFORTH. Taxonomic and bionomic observations on a Floridian panurgine bee, Perdita (Hexaperdita) graenicheri Timberlake (Hymenoptera: Andrenidae) 107 PULAWSKI, W.J. and H.K. COURT. A review of the genus Hingstoniola (Hymenoptera: Sphecidae: Crabronini) . . . 255 QUELLER, DC, J.E. STRASSMANN, and C.R. HUGHES. Genetic relatedness and population structures in primi- tively eusocial wasps in the genus Mischocyttarus (Hymenoptera: Vespidae) 81 ROSEN, D., Y. ARGOV, and J.B. WOOLLEY. Biological and taxonomic studies of Chartocerus subaeneus (Hym- enoptera: Signiphoridae), a hyperparasite of mealybugs 241 STOLTZ, D. and J.B. WHITFIELD. Viruses and virus-like entities in the parasitic Hymenoptera 125 INSTRUCTIONS FOR AUTHORS Inside back cover 2*3 5QCIETV, Journal of Hymenoptera Research Volume 2, Number 1 August 1993 ISSN 1070-9428 CONTENTS BROTHERS, D. J. and J. M. CARPENTER. Phylogeny of Aculeata: Chrysidoidea and Vespoidea 227 DAVIDSON, D. W. and D. McKEY. The evolutionary ecology of symbiotic ant-plant relationships 13 GENISE, J. F. and L. S. KIMSEY. Revision of the South American thynnine genus Elaphroptera Guerin-Meneville (Hymenoptera: Tiphiidae) 195 HERATY, J. M., D. P. WOJIC and D. P. JOUVENAZ. Species of Orasema parasitic on the Solenopsis saevissima- complex in South America (Hymenoptera: Eucharitidae, Formicidae) 169 HEYDON, S. L. Syntomopus Walker: the Nearctic species with a review of known host associations (Hymneoptera: Ptero- malidae) 107 KAZENAS, V. L. and B. A. ALEXANDER. The nest, prey and larva of Entomosericus knufmani Radoszkowski (Hymenoptera: Sphecidae) 221 de MELO, G. A. R. and L. A. de O. CAMPOS. Nesting biology of Microstigus myersi Turner, a wasp with long-haired larvae (Hymenoptera: Sphecidae, Pemphredoninae) 183 MENKE, A. S. A new species otApocharips from Costa Rica (Hymenoptera: Cynipoidea, Charipidae) 97 PIEK, T. New neurotoxins from venom of aculeate Hymenoptera: a contribution to the knowledge of stinging behavior 101 RASNITSYN, A. P. Archaeoscolinae, an extinct subfamily of scoliid wasps (Insecta: Vespida = Hymenoptera: Scoliidae) 85 SHAW, S. R. Systematic status of Eucystomastax Brues and characterization of the Neotropical species (Hy- menoptera: Braconidae, Rogadinae) 1 TOGASHI, I. Sawflies of the genus Perineum Hartig from Japan (Hymenoptera: Tenthredinidae) 189 WARD, P. S. Systematic studies on Psucdomyrmex acacia-ants (Hymenoptera: Formicidae: Pseudomyrmecinaw) 117 SCIENTIFIC NOTE WILLINK, A. AND A. R. ALSINA. On Odynerus rachiphorus Schletterer, a Masarinae (Trimeria), not a Eumeninae (Hy- menoptera, Vespidae) 303 INTERNATIONAL SOCIETY OF HYMENOPTERISTS Organized 1982; Incorporated 1991 OFFICERS FOR 1993 George C. Eickwort, President Donald L. J. Quicke, President-Elect Michael E. Schauff, Secretary Gary A. P. Gibson, Treasurer Paul M. Marsh, Editor Subject Editors John Huber, Arnold Menke, David Rosen, Mark R. Shaw, Robert Matthews All correspondence concerning Society business should be mailed to the appropriate officer at the following addresses: President, Department of Entomology, Cornell University, Ithaca, New York 14853; President-Elect, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, England; Secretary and Editor, c/o Department of Entomology, NHB 168, Smithsonian Institution, Washington, D.C. 20560, U.S.A.; Treasurer, Biological Resources Division/CLBRR, Agriculture Canada, K.W. Neatby Building, Ottawa, Ontario, Canada K1A 0C6. Membership. Members shall be persons who have demonstrated interest in the science of entomology. Annual dues for members are $25.00 (U.S. currency) per year. Journal. The journal is published once a year by the International Sociey of Hymenopterists, c/o Department of Entomology NHB 168, Smithsonian Institution, Washington, D.C. 20560, U.S.A. Members in good standing receive the journal of Hymenoptera Research. Nonmember subscriptions are $50.00 (U.S. currency) per year. All remittances should be made payable to the International Society of Hymenopterists. The Society does not exchange its publications for those of other societies. Please see inside back cover of this issue for information regarding preparation of manuscripts. Statement of Ownership Title of Publication: Journal of Hymenoptera Research. Frequence of Issue: Once a year (currently). Location of Office of Publication, Business Office of Publisher and Owner: International Society of Hymenopterists, c/o Department of Entomology, NHB 168, Smithsonian Institution, Washington, D.C. 20560, U.S.A. Editor: Paul M. Marsh, Systematic Entomology Laboratory, c/o Department of Entomology, NHB 168, Smithsonian Institution, 10th and Constitution NW, Washington, D.C. 20560, U.S.A. Managing Editor and Known Bondholders or other Security Holders: none This issue was mailed 30 September 1993 KBrourrWiiK) Fig. 1. Color habitus of Aleiodes melanopterus (Erichson) female, oblique antero- lateral view. J. HYM. RES. 2(1), 1993 ppl-1 1 Systematic Status of Eucystomastax Brues and Characterization of the Neotropical Species (Hymenoptera: Braconidae: Rogadinae) Scott Richard Shaw Department of Plant. Soil, and Insect Sciences. University of Wyoming. Laramie, Wyoming 82071-3354 U.S.A. Abstract. — Rogas melanopterus Erichson is found to be the oldest available name for Eucystomastax bicolor Brues, the type-species of Eucystomastax Brues. This distinctive Neotropical species has six available species names, and has been placed in three different genera: Rogas, Macrostomion, and Eucystomastax. Possible placements in Rogas or Macrostomion are evaluated and rejected on phylogenetic grounds, since Eucystomastax lacks critical synapomorphies of those lineages. Phylogenetic affinity of Eucystomastax with the Aleiodes-group is demonstrated. Eucystomastax is shown to comprise a monophyletic cluster of species including Rogas melanopterus Erichson, Macrostomion lucidus Szepligeti. Aleiodes mexicanus Cresson, Rogas politiceps Gahan, and one newly described species, Aleiodes flavistigma Shaw. Full generic validity of Eucystomastax is rejected on the grounds that continued recognition as a distinct genus results in a paraphyletic Aleiodes, and the Eucystomastax lineage can be clearly derived from within North America Aleiodes. Eucystomastax is reduced in rank to the status of a subgenus of Aleiodes comprising those New World species with infumate wings, enlarged oral space, and swollen maxillary palpi. On the basis of synapomorphic color patterns and transitional sculpture characters the Neotropical species are argued to comprise a monophyletic group whose nearest relative is the North American species, Aleiodes politiceps (Gahan). Neotropical Eucystomastax includes flavistigma NEW SPECIES, lucidus (Szepligeti ). melanopterus (Erichson), and mexicanus Cresson. A subgeneric diagnosis, key to species, and species descriptions are given for the Neotropical species. The braconid subfamily Rogadinae comprise a diverse lineage of koinobiont endoparasitoids of lepidopteran larvae (Shaw & Huddleston, 1991). Among species of the tribe Rogadini pupation is internal, within the host cuticle, resulting in a distinctive shrunken caterpillar mummy (Shaw, 1983). The Neotropical rogadine fauna is quite diverse and challenging taxonomically. Although the problem arises in part from the tremendous species richness and the fact that many species are undescribed, equally challenging is the difficult task of sorting out the chaotic taxonomic history of the already named species. The older literature is often difficult to acquire and the types of Neotropi- cal rogadines are mostly scattered around various European and North American museums. Added to this is confusion created by the fact that many of the original generic placements were wrong and have not been corrected in even the most recent catalogues. The purpose of this paper is to clarify the confused history pertaining to the unique Neo- tropical lineage Eucystomastax Brues and to evalu- ate the phylogenetic affinities and validity of the "genus." This study was initiated in support of a collaborative effort to develop an identification manual for the genera of Neotropical Braconidae, which requires that the systematic status of various genera be clarified. METHODS Terminology mostly follows that used by Marsh, Shaw & Wharton ( 1 987 ) for Braconidae and Marsh (1989) for Aleiodes. Microsculpture terminology follows that outlined by Harris (1979). The follow- ing abbreviations are used in the diagnoses: BL Body length, in dorsal view, excluding antenna and ovipositor. FWL Fore wing length. F# Flagellomere #. MS Malar space. EH Maximum eye height. EW Maximum eye width. Journal of Hymenoptera Research TW Temple width. OS Oral space, maximum width in anterior view. OOD Ocell-ocular distance: shortest distance from eye margin to lateral ocellus. OD Ocellus diameter: maximum width of lateral ocellus. T# Tergum #. OL Ovipositor length. HBTL Hind basitarsus length. HTS Hind tibial spur length (longest spur). R# Radius segment #. Abbreviations for museums can be found in the Acknowledgments section. HISTORICAL OVERVIEW OF THE SPECIES Eucystomastax melanopterus One of the commonest and most distinctive elements of the Neotropical rogadine fauna is a large orange and black species with infumate wings, large oral space, and swollen maxillary palpi (Fig- ure 1 ). The first author to describe this species was Erichson ( 1 848 ), who named it Rogas melanopterus. Although banded wings are fairly common among tropical rogadines, completely infumate wings are rather unusual. In spite of the fact that the specific epithet rather obviously refers to the unusual dark wings of this species, the correct application of this name has long remained obscure. Szepligeti (1904) described this species as Macrostomion pemvianum based on a specimen from Peru. The genus Macrostomion Szepligeti had been described four years earlier based on a specimen from New Guinea (Szepligeti, 1900). Szepligeti (1906 (described another closely related species, Macrostomion lucidus, based on a speci- men from Bolivia. Although the South American species differfrom the New Guinean Macrostomion in a number of characters, Szepligeti grouped the species together in one genus based on the swollen maxillary palpus. Cameron (1911) described the species three more times, based on three specimens from British Guiana (Guyana). He placed this species in Rhogas [=Rogas], but gave no explanation for his generic placement. Cameron was the first author to treat a series of specimens (two females and one male), and although the variation presented was very slight, he elected to recognize each of these as a separate species {Rhogas rufithorax, Rhogas fortipalpis, and Rhogas forticarinatus). The char- acters used by Cameron to separate these "species" were very slight differences in color and sculpture, which are now recognized to fall within the range of normal infraspecific variation. Brues (1912) described this species as a new genus and species, Eucystomastax bicolor, based on a single male specimen from Brazil. Brues noted a general similarity in habitus to Rhogas [=Rogas], yet he concluded that the species must be placed in a separate genus because of its "dilated palpi." He noted that certain other rogadine genera also have similarly modified palpi (Macrostomion Szepligeti, Pelecystoma Wesmael, and Cystomastax Szepligeti). However, he observed that Macro- stomion and Pelecystoma both have "flattened or leaf-like" dilations of the palpi, therefore precluded relationship with those genera. He noted that Cystomastax has slit-like metathoracic spiracles and a petiolate metasoma, and distinguished Eucystomastax as a separate genus on the basis of its round metathoracic spiracles and sessile metasoma. Subsequent to Brues' study, virtually no studies have evaluated this taxon. Shenefelt (1969) stud- ied and redescribed the New Guinean type-species of Macrostomion (Macrostomion bicolor Szepligeti), but he did not study or discuss the Neotropical species that Szepligeti (1906) had placed in this group. Shenefelt (1975) cataloged the world fauna of Rogadinae, but his treatment of species is largely a literature compilation and does not address the difficult taxonomic problems per- taining to this subfamily. Consequently, the spe- cies discussed above, for which the correct specific epithet is melanopterus Erichson, is listed in Shenefelt ' s catalog under six separate species names and classified under three different genera! PHYLOGENETIC AFFINITIES OF Eucystomastax AND EVALUATION OF ITS TAXONOMIC STATUS Based on the above discussion and comparison Volume 2, Number 1, 1993 of the holotype specimens, it can now be estab- lished that melanopterus Erichson is the oldest available name for bicolor Brues, the type-species of Eucystomastax. Establishing the correct generic placement of melanopterus Erichson is, however, a more complex problem requiring a modern per- spective on rogadine evolution and classification. For many years, the correct inteipretation of Rogas Nees, 1818 and Aleiodes Wesmael, 1838 remained obscure, resulting in considerable confu- sion in the literature. Earlier authors used the names interchangeably, and until just recently the majority of New World rogadine species were classified under Rogas. The name Pelecystoma Wesmael. 1 838 was held distinct for a relatively small group- ing of Holarctic species with a swollen maxillary palpus. The situation was clarified by van Achterberg ( 1982) through a reexamination of the type-species that revealed that Pelecystoma is a junior synonym of Rogas and that Aleiodes is the valid name for many species formerly classified under Rogas. Diagnoses for Rogas and Aleiodes based on a study of Afrotropical and Western Pale- arctic species were provided by van Achterberg (1991). Within the tribe Rogadini, two clades predomi- nate. One lineage, here called the Rogas-group, is characterized by at least two apomorphies: the presence of a row of flattened setae along the inner margin of the apex of the hind tibia and the presence of an enlarged blunt basal lobe on the tarsal claw. The ovipositor has diagnostic value in that it is usually as long as or longer than the hypopygium and is curved. The Rogas-group comprises Rogas and several other closely related genera including Macrostomion, Cystomastax, Spinaria, and Triraphis. This lineage is cosmopolitan, but it is particularly species-rich in tropical areas where it comprises about 90% of the rogadine fauna (per- haps 300 or more species worldwide, most of which are undescribed). The Rogas-group is ecologically distinctive, in that they attack mostly sluggish and slug-like larvae (slow moving, exposed feeders), many of which are gregarious feeders. The known hosts are mostly relatively primitive exposed-feed- ing macrolepidopterans such as Limacodidae or Zygaeniidae, but some parasitize lycaenid or riodinid larvae. Host mummies typically are stuck naturally to the substrate by host secretions, and no "glue hole" ( a ventral hole made by the parasitoid larva to stick the mummy to the substrate) is formed. The exit hole from the host mummy is crude and irregu- lar, usually comprising multiple ragged tears. The hooked pronotal spine of Spinaria may be an adap- tation for escaping from the host mummy. Mark Shaw (1983) suggested that this group (at least Rogas) "arose through an early response to the naked feeding habit in Lepidoptera." A second major rogadine lineage, here called the Aleiodes-group, is also characterized by several apomorphies: non-foveate mesopleural sternaulus, first intercubitus postfurcal relative to the recurrent vein, reduction and loss of the propodeal areola, propodeum with a median carina, and presence of a carinate anterior margin on tergum 2 that typi- cally converges medially into a median percurrent carina, often with an associated polished anteromedial triangular area. In contrast to the Rogas-group. the ovipositor is usually much shorter than the hypopygium and is straight. This lineage is also cosmopolitan, but it is particularly species- rich in temperate areas and predominates through- out the Holarctic region. The Aleiodes-group com- prises at least 200 Aleiodes species worldwide (as defined by van Achterberg, 1991) and possibly a few other minor genera including Tetrasphaeropyx and Yelicones. Tetrasphaeropyx is a unique North American lineage comprising one described and at least seven undescribed species, differing from Aleiodes only by having a metasomal carapace. The phylogenetic position of Tetrasphaeropyx has not been established, therefore it cannot be denied that this small "genus" may only be a specialized offshoot of Aleiodes. Yelicones is another small genus of worldwide distribution that is currently being revised by D. Quicke. The phylogenetic position of Yelicones is controversial, and van Achterberg ( 1991 ) has suggested that it should be transferred to another subfamily, the Betylobraconinae. Since Yelicones mummifies its host larva and possesses the synapomorphies of the Aleiodes-group, it is unlikely that this genus should be removed from the Rogadini (unless the Betylobraconinae are discovered to share this synapomorphy); hopefully Dr. Quicke's study will resolve this issue. With these minor exceptions, the Journal of Hymenoptera Research Aleiodes-group as defined here corresponds almost exactly to the diagnosis of the genus Aleiodes provided by van Achterberg ( 1991 ). Ecologically, the Ale iodes-group is quite distinctive. The known hosts of the Aleiodes-group are mostly relatively advanced exposed-feeding macrolepidopterans such as noctuoidorgeometroid larvae. Mark Shaw ( 1983) summarized several biological characteris- tics, which may be construed as further apomorphies of this group. They attack early instars of exposed "macrolepidoptera," attacking the host away from foodplant substrates as readily as on them. They employ venoms that cause short-lived temporary paralysis as a handling device facilitating oviposi- tion, but having no other detectable physiological effect on the host. They oviposit loosely into the host haemocoel as a separate action distinct from injecting venom. They kill the host in a middle instar, forming a somewhat contracted mummy. Lastly, most species cut a ventral "glue hole" in the prothoracic region of the host larva, by which the mummy is attached to the substrate. Shaw ( 1983) suggested that the lack of "glue holes" in some species is a secondary adaptation to survival in wetland habitats, because loose mummies can float. Because of the tremendous species-richness of the genus, it is difficult to establish the monophyly of Aleiodes at the present time. However, it appears that the "glue hole" may be the best autapomorphy for the genus. It is present in all the Aleiodes host mummies examined during my studies, but it does not appear to be present in Yelicones mummies. Host mummies for Tetrasphaeropyx were not avail- able for study. My preliminary studies, and unpublished stud- ies by P. Marsh, indicate that the Rogas-group and the Aleiodes-group are sister lineages, based on a unique ultrastructural character. All species exam- ined so far have 2-12 striated accessory spines along the basal 1/8 to 3/4 of the tarsal claw. In contrast, the remaining rogadine genera, such as Stiropius, Polystenidea, and Rhysipolis, have simple claws without such spines. This is compatible with Whitfield's (1988) supposition that the rogadine parasitoids of leaf-miners (Stiropius, Polystenidea, Viridipyge) are probably one of the most basal lineages of the tribe. Eucystomastax belongs to the Aleiodes-group, since melanopterus possesses the apomorphies in- dicating placement in this group: absence of a propodeal areola and presence of an undivided median propodeal carina (Fig. 3), presence of a carinate anterior margin along tergum 2 that con- verges medially into a median percurrent carina with an associated polished anteromedial triangu- lar area (Fig. 6), and a straight ovipositor that is distinctly shorter than the hypopygium (Fig. 7). Furthermore, melanopterus lacks the apomorphies of the Rogas-group. The apex of the hind tibia lacks a row a flattened setae (Fig. 4) and the tarsal claw lacks a blunt basal lobe (Fig. 5). The swollen maxillary palpus and large oral space are the only characters by which Eucysto- mastax differs from typical Ale iode s. In addition to melanopterus Erichson, there are two other valid Neotropical species, lucidus Szepligeti and mexicanus Cresson, that share these apomorphic traits and are here assigned to Eucystomastax. A survey of all known North American Aleiodes- group species revealed only one other species that shares apomorphies with Neotropical Eucysto- mastax species. Aleiodes politiceps (Gahan) pos- sesses several apomorphic traits indicating that this species is possibly the sister-group of the Neotropi- cal Eucystomastax lineage: enlarged oral space (Fig. 2), mesonotum and mesopleuron with pre- dominantly smooth sculpture (Fig. 3), infumated wings (Fig. 1 ), hind tibia and tarsus densely setose (Fig. 4), pectinate tarsal claws with 4-9 large acces- sory spines (Fig. 5), and sculpturing of terga 1-3 predominantly longitudinally strigose (Fig. 6). Brues (1912) has already demonstrated that the swollen maxillary palpus occurs as several distinct character states in different rogadine lineages, so there is a basis for concluding that the character is subject to convergent evolution. One relevant fact that has not been previously emphasized is that the swollen maxillary palpus character is sexually di- morphic in Rogas. occurring only in the males, whereas it occurs in both males and females of Eucystomastax. The swollen maxillary palpus is generally absent in the Aleiodes-group, but in Aleiodes politiceps the maxillary palpus is dis- tinctly thickened in both females and males. Al- though it is not swollen as in Eucystomastax, the Volume 2, Number 1, 1993 thickened condition in politiceps may be the first step in a transition series leading to the extreme condition as expressed in melanopterus Erichson. A complete phylogenetic analysis of the Ale iodes-grou\> is not possible at the present time, but a preliminary analysis of 14 species indicates that Eucystomastax is an offshoot of a relatively apical lineage of New World Aleiodes that also comprises the terminalis and parasiticus species- groups. Because the continued recognition of Eucystomastax as a genus would result in a paraphyletic Aleiodes, it is necessary that the ge- neric concept of Aleiodes be expanded to include Eucystomastax, which becomes a junior synonym of Aleiodes. However, since Eucystomastax is ob- viously a monophyletic and distinctive lineage and the name is already available, it would seem worthwhile to maintain the name Eucystomastax as a valid subgenus for the four Neotropical species and the closely allied North American species, Aleiodes politiceps. This is not meant to suggest that all remainingA/e/oA\vcan be placed in a single subgenus (Aleiodes), only that Eucystomastax is a monophyletic group within the genus that is wor- thy of recognition, but cannot be treated as a valid genus ( other Aleiodes are considered incertae sedis pending further study). As far as is known, Eucystomastax does not occur in other biogeo- graphic realms. In the taxonomic treatment which follows, cov- erage is limited to the Neotropical species because the North American species of Aleiodes are cur- rently being revised by the author, and the species politiceps will be fully diagnosed and discussed in that paper. CHARACTERIZATION OF NEOTROPICAL Aleiodes (Eucystomastax) SPECIES Diagnosis: Head and legs mostly black; mesosomal and metasomal color varying from yellowish-brown to bright orange to black; BL 6.75-9.33 mm; FWL 5.50-8.70 mm; flagellum with apical flagellomere terminating in a sharp point; 50-68 flagellomeres; MS/EH 0. 1 2-0.3 1 ; TW/ EW 0.35-0.75; occipital carina variable: some- times weak ventrally and not meeting hypostomal carina, sometimes meeting hypostomal carina; OS/ MS 2. 1 5-4.33; OOD/OD 0.70-1 .50; face smooth to rugose or rugo-punctate; frons smooth; vertex smooth; temple smooth; maxillary palpus swollen, especially segments 2 and 3, and sometimes 4; propleuron smooth to rugose; mesonotum smooth; notauii scrobiculate to smooth, or sometimes ab- sent; scutellum smooth; mesopleuron smooth; epicnemial carina complete to reduced or absent; sternaulus smooth to absent; propodeum rugose to smooth dorsally. carinate-rugose basally, to en- tirely smooth; median propodeal carina strong and complete; metasoma comprising 7 visible terga; Tl length/width 0.9 1 - 1 . 1 8; T2 length/width 0.69-0.82; T3 length/width 0.40-0.54; Tl varying from longi- tudinally aciculate to rugo-striate to smooth with scattered punctations; T2 varying from longitudi- nally aciculate to rugo-striate to smooth with scat- tered punctations; T3 varying from longitudinally aciculate basally, with apical 1/2 smooth, to rugo- striate from extreme base up to entire basal 1/2, otherwise smooth, to entirely smooth with scat- tered punctations; T4 entirely smooth, but some- times with scattered punctations; median carina present on Tl and T2; OL/HBTL 0.18-0.96 (un- known for lucidus); tarsal claw pectinate, with 4-9 accessory spines becoming gradually smaller ba- sally; HTS/HBTL 0.29-0.35; hind coxa dorsally smooth to punctate; wings deeply infumate; R1/R2 0.37-0.50; R 1/recurrent 0.39-0.60; nervulus place- ment beyond basal vein/nervulus length 1 .39-2.67; radiellen cell gradually widening; basella/mediella 0.57-0.85; postnervellus present. Discussion: Eucystomastax species are quite distinctive among the Neotropical rogadine fauna because of their black head and deeply infumate wings (Fig. 1 ). Although banded wings are rather common among Neotropical rogadines. completely dark wings are rather unusual (probably synapomorphic) and are known only in a few relatively less common Rogas species (an evolu- tionary convergence). The combination of a en- tirely black head and mostly black wings will easily separate Eucystomastax species from most other Neotropical rogadines, even without the aid of a microscope. Character transformations both in colorpatterns and morphology (especially mesosomal and metasomal sculpture ) suggest that the melanopterus Journal of Hymenoptera Research species-group is a monophy letic group whose near- est relative is the North American species, Aleiodes politiceps (Gahan). All four Neotropical Eucystomastax species have a black head (synapomorphy ) and reduced metasomal sculpture from the coarse sculpture seen in politiceps (a synapomorphic transition series). It is hypothesized that flavistigma, lucidus, and melanopterus com- prise a monophyletic group based on the synapomorphic black metasoma. Of these, lucidus has the most extreme apomorphic reductions in body sculpturing. The relationships of these three species are not yet resolved, but the autapomorphies and more limited distributions of flavistigma and lucidus suggest that each may be separate offshoots from melanopterus or melanopterus-tike ances- tors. The relationships proposed here among Eucystomastax species are as follows: politiceps + [mexicanus + {flavistigma + melanopterus + lucidus}]. Although the hosts of the Neotropical species are not known, the known hosts of North American politiceps suggest that moderately large noctuid larvae are the most likely hosts of this group. KEY TO NEOTROPICAL EUCYSTOMASTAX SPECIES Metasoma black apically or mostly black (Fig. 1); South America 2 Metasoma entirely yellowish brown; Mexico mexicanus Cresson Notauli distinct although smooth (Fig. 3); epicnemial carina entirely present 3 Notauli absent, mesonotum entirely smooth; epicnemial carina effaced dorsally or completely absent lucidus (Szepligeti) (1) 3 (2) Pterostigma yellow .flavistigma, new species Pterostigma black melanopterus (Erichson) Aleiodes (Eucystomastax) flavistigma Shaw, new species Description of female. — (83 specimens). Head, mesosoma anteriorly, most of legs apically, and mesosoma apically black; mesosoma posteriorly reddish brown; pterostigma and area below pterostigma bright yellow; coxae, propodeum, and Tl-6 varying from reddish brown to black; BL 6.75-8.50 mm; FWL 5.50-7.25 mm; flagellum with 55-68F; MS/EH 0.17-0.22; TW/EW 0.44-0.59; occipital carina meeting hypostomal carina; OS/ MS 2.40-4.0; OOD/OD 1.25-1.50; face smooth; maxillary palpus swollen, especially segments 2, 3, and 4; propleuron smooth; mesonotum smooth, postero-medially with a short carina; notaulus smooth; stemaulus smooth; epicnemial carinacom- plete; propodeum smooth dorsally, carinate-rug- ose basally ; T 1 length/width 0.9 1 - 1 . 1 1 ; T2 length/ width 0.70-0.73; T3 length/width 0.43-0.49; Tl rugo-striate; T2 rugo-striate; T3 smooth; T4 smooth; OL/HBTL 0.22-0.96; pectin of tarsal claw with 4- 9 spines; HTS/HBTL 0.29-0.35 ; hind coxa dorsally smooth; R1/R2 0.37-0.40; Rl/recurrent vein 0.39- 0.56: nervulus position beyond basal vein/nervulus length 1.56-2.22; basella/mediella 0.57-0.85. Description of male. — ( 1 32 specimens). Essen- tially as female except flagellum with 50-62F. Discussion. — This species is morphologically within the range of usual variation for melanopterus, but differs dramatically in color patterns. Speci- mens of A. flavistigma are quite distinctive in having the pterostigma and the area of the forewing just below the pterostigma colored bright yellow. Additionally, the light colored areas of the mesosoma and metasoma are dark reddish brown ( rather than orange as in melanopterus), and greatly reduced in extent (some males are almost entirely black except for the mesopleuron and propodeum which are reddish brown). The only significant Volume 2, Number 1, 1993 morphological variation between these species is in the surface sculpture of metasomal tergum 3, which is smooth in A. flavistigma. Although vari- able in A. melanopterus (and sometimes smooth), the coarse sculture of tergum 2 often continues onto the basal half of tergum 3 in many melanopterus specimens. In spite of little morphological diver- gence, it seems reasonable to treat this as a separate species because typical A. melanopterus occurs sympatrically. with no intermediates. The bright yellow stigma suggests the possibility that A. flavistigma is part of a tropical mimicry ring, and it is possible that it evolved from a population of melanopterus. Etymology. — From the Latin flavus meaning yellow, and Greek stigma meaning spot, in refer- ence to the bright yellow pterostigma. Distribution. — Brazil, SantaCatarina and Parana Provinces. Seasonal occurrence from August through March. Types. — Holotype female: Brazil, Nova Teutonia, 27.1 1 S. 52.23 W, 300-500m, February 1967, Fritz Plaumann (CNC). Paratypes: 82 fe- males, 132 males, same data as holotype except collection dates ranging from February 1 962 through December 1968 (CNC. RMSEL, USNM); 1 fe- male, Brazil, Parana, Pitangueiras, 24.41 S. 51.46 W. 700m, March 1963, F. Plaumann (MCZ); 1 female, Brazil, Parana, Bocaiilva do sol, 26.08 S, 49.04 W, 1000m, March 1963, F. Plaumann (MCZ); 2 females, 1 male, Parana, Prudentopolis, 23-25 February 1969, C. Porter & A. Garcia (MCZ): 1 female. Parana, Laranjeiras, 25.24 S, 52.23 W, 900m, (no date). F. Plaumann (MCZ); 1 female, 1 male, same data as holotype except 18 January & 25 February 1963 (MCZ). Aleiodes (Eucystomastax) lucidus (Szepligeti), new combination. Macrostomion lucidus Szepligeti, 1906: 609. Ho- lotype male, Bolivia, Mapiri (TMB, #1658) [examined]. Diagnosis. — Body color black, except pronotum laterally and mesothorax orange; BL 8.50-9.33 mm; FWL 8.67-8.70 mm; flagellum with 63F(miss- ing beyond F31 in holotype); MS/EH 0.16-0.31; TW/EW 0.35-0.75 : occipital carina weak ventrally, not meeting hypostomal carina; OS/MS 2.15-2.31; OOD/OD 1.0-1.30; face rugopunctate; temple smooth; maxillary palpus swollen, especially seg- ments 2-4; propleuron smooth; notauli absent; epicnemial carina weak, especially dorsally, or entirely absent; sternaulus absent; propodeum smooth; median propodeal carina present; metasoma comprising 7 visible terga; Tl length/ width 1.1 1-1.18; T2 length/width 0.75-0.80; T3 length/width 0.43-0.54; T1-T4 smooth with scat- tered punctations; OL/HBTL unknown (males only); pectin of tarsal claw pectinate with 8-9 spines; HTS/HBTL 0.29-0.33; hind coxa dorsally punctate; R1/R2 0.49-0.50; Rl /recurrent vein 0.55- 0.60; nervulus placement beyond basal vein / nervulus length 1.39-1.50; basella/mediella 0.66- 0.83. Distribution. — Bolivia. Other Specimens Examined. — Bolivia: 1 male, Santa Cruz, J. Steinbach (MCZ). Comments. — This species is the rarest of all Eucystomastax in collections, and known only from the male. In appearance it is quite similar to Aleiodes melanopterus (Erichson), except that lucidus has a larger body size, less extensive bright orange color on the metasoma, and generally smoother sculpture. In lucidus. terga 2+3 are mostly smooth and shining (except for scattered punctations), the mesonotum is entirely smooth and lacking notauli, and the epicnemial carina is greatly reduced or entirely absent. Although simi- lar to melanopterus in size and color, the unusual sculpturing (especially the complete loss of notauli and reduction of the epicnemial carina) is unusual and suggests that lucidus is a distinct species. From the apomorphic color pattern (bright orange mesosoma and black metasoma) it might be in- ferred that lucidus and melanopterus are sister- species. Aleiodes (Eucystomastax) melanopterus (Erichson). new combination (Figs. 1-7) Rogas melanopterus Erichson, 1848:588. Holo- type female, British Guiana, Schomburgk (ZMHB) [examined]. Journal of Hymenoptera Research Macrostomion peruvianum Szepligeti, 1904: 193. Holotype male, Peru, Marcapata (TMB, #1657) [examined]. NEW SYNONYM. Rhogas rufithorax Cameron, 1911:313. Holotype male, British Guiana (BMNH, #3c232) [exam- ined]. NEW SYNONYM. Rhogas fortipalpus Cameron, 191 1:314. Holotype female, British Guiana (BMNH, #3c234) [ex- amined]. NEW SYNONYM. Rhogas forticarinatus Cameron, 1911:314. Holo- type female, British Guiana (BMNH, #3c234) [examined]. NEW SYNONYM. Eucystomastax bicolor Brues, 1912:223. Holo- type male, Brazil, Para, W.M. Mann (MCZ, #29924) [examined]. NEW SYNONYM. Diagnosis. — Body color as in Fig. 1: head, most of legs apically, and mesosoma apically, all black; mesosoma mostly bright orange; coxae, propodeum, and Tl-6 varying from bright orange to black; BL 6.75-8.50 mm; FWL 5.50-7.25 mm; flagellum with 50-56F (males) 56-68F (females); MS/EH 0.17-0.22; TW/EW 0.44-0.59; occipital carina meeting hypostomal carina; OS/MS 2.40- 4.0; OOD/OD 1.25-1.50; face smooth; maxillary palpus swollen, especially segments 2, 3, and 4; propleuron smooth; mesonotum smooth, postero- medially with short carina; notaulus smooth; sternaulus smooth; epicnemial carina complete; propodeum smooth dorsally, carinate-rugose ba- sally; Tl length/width 0.91-1.1 1; T2 length/width 0.70-0.73; T3 length/width 0.43-0.49; Tl rugo- striate; T2 rugo-striate; T3 rugo-striate from ex- treme base up to entire basal 1 /2, otherwise smooth; T4 smooth; OL/HBTL 0.22-0.96; pectin of tarsal claw with 4-9 spines; HTS/HBTL 0.29-0.35; hind coxa dorsally smooth; R1/R2 0.37-0.40; Rl/recur- rent vein 0.39-0.56; nervulus position beyond basal vein/nervulus length 1.56-2.22; basella/mediella 0.57-0.85. Distribution. — Widely distributed and relatively common throughout the Amazonian basin of South America from Suriname south to northern Argen- tina, west to eastern Peru. Not recorded east of the Andean Cordillera or in Central America. Seasonal occurrence from 5 September through 1 0 May, with collecting records from each intervening month. Other Specimens Examined. — (94 females and 310 males) from the following localities. Argen- tina: Jujuy: Alto la Vina, Posta Lozano; Salta: Abra Grande, nr. Aguas Blancas, 24 km NW Aguas Blancas, Camp. Jakulica, Oran, nr. Pocitos, Rio Pescado (Est. YPF), Tartagal, nr. Vespucio; Tucuman: El Nogalar, Horco Molle, Las Cejas, Quebrada Lules, S. Pedro Colalao, Tacunas, Trancas, (C. Porter, E. Willinck, Arnau) (CNC, MCZ). Bolivia: Chapare, El Palmar; 100 km N. Bermejo, Chulomani, La Paz, Mapiri, Santa Cruz (A. Garcia, C. Porter, J. Steinbach, L. Pena) (CNC, MCZ). Brazil: Goias, Goiania; Mato Grosso, Burtiti;NovaTeutonia: Santa Catarina; Sao Paulo: Sao Paulo (E. Munroe, C. Porter. F. Plaumann) (CNC, MCZ, FUG). Ecuador: Napo, Tena; Pompeya (L. Huggert, Pena, M. Sharkey, L. Masner) (CNC, MCZ). Paraguay: Molinascue, Villarica (F. Schade)(MCZ). Peru: CuzcoDep.:Quincemil; Madre de Dios: Tingo Maria; Junin, Satipo (A. Garcia, L. Pena, C. Porter, L. Huggert) (CNC, MCZ). Comments. — Although the body coloration var- ies considerably, the basic pattern for the species is quite distinctive: mesosoma mostly orange, and head, wings, legs, and metasoma, at least apically. black. The most notable variation occurs on the pronotum, coxae, trochanters, metathorax, propodeum, and metasomal terga 1-5 which vary from entirely orange to entirely black. Although the metasoma is commonly entirely black, some- times terga 1-3, and more rarely terga 4-5, are orange or orange irregularly infused with black. This is the most commonly collected Eucystomastax species. Aleiodes (Eucystomastax) mexicanus Cresson Aleiodes mexicanus Cresson, 1869: 378. Holotype female, Mexico (Prof. Sumichrast) (ANSP. #1658) [examined]. Diagnosis. — Head, antenna, legs, and pronotum black; mesosoma otherwise and metasoma yellow- ish orange; BL 7.0-8.50 mm; FWL 6.5-8.0 mm; flagellum with 56-62F; MS/EH 0.12-0.15; TW/ EW 0.53-0.75; occipital carina weak ventrally, not meeting hypostomal carina; OS/MS 3.50-4.33; Volume 2, Number 1, 1993 Figs. 2-7. Aleiodes ntelanopterus (Erichson): 2, lower portion of head of female, anterior view showing large oral space and swollen maxillary palpus; 3, mesosoma of female, doi so-lateral view showing predominantly smooth sculpture of mesonotum, mesopleuron, and propodeum (note median carinae of mesonotum and propodeum); 4, hind leg of female, lateral view showing apex of tibia, tibial spurs, and base of basitarsus; 5, hind tarsal claws of female, lateral view showing basal pectination; 6, metasoma of female, dorso-lateral view showing microsculpture of tergum 1, tergum 2. and base of tergum 3; 7, apex of metasoma of female, lateral view showing hypopygium and short ovipositor. 10 Journal of Hymenoptera Research OOD/OD 0.70-0.9 1 ; face rugose; maxillary palpus swollen, especially segments 2 and 3; propleuron rugose, except smooth laterally; notaulus scrobiculate; stemaulus smooth; epicnemial carina complete; propodeum rugose; Tl length/width 1.14- 1.17; T2 length/width 0.69-0.82; T3 length/width 0.40-0.50;; Tl longitudinally aciculate: T2 longi- tudinally aciculate; T3 longitudinally aciculate basally, apical 1/2 smooth; T4 smooth; median carina present on T1-T2; OL/HBTL 0.18-0.60; pectin of tarsal claw with 8 spines; HTS/HBTL 0.30-0.35; hind coxa dorsally smooth; R1/R20.37- 0.44; R 1 /recurrent vein 0.39-0.50; nervulus place- ment beyond basal vein/nervulus length 2.0-2.67; basella/mediella 0.67-0.73. Distribution. — Mexico. The one record from Mississippi needs confirmation. This could be an accidental introducation and the species may not be established. Other Specimens Examined. — Mexico: 1 fe- male, Orizaba, 25.vii.1956, R. & K. Dreisbach (USNM); 1 female, Ver., Santecomapan, 10 June 1969, J. E. H. Martin (CNC); 1 female, Sin., 27 mi. E. Villa Union, 26 July 1 964, H. F. Howden (CNC); 32 mi. W. San Cristobal, Jet. Hwy. 190-195, Chis., at light, 1 1 June 1969, A. Mutuuru (CNC). USA: 1 male, Mississippi, Lafayette Co., May-June 1960, F. M. Hall (CNC). Comments. — A relatively rare species in col- lections, that is similar to both the Neotropical species A. melanopterus (Erichson) and the Nearc- tic species A. politiceps (Gahan). However, the metasoma of melanopterus (Erichson) is black, at least apically, while the body of politiceps is en- tirely orange. In this regard mexicanus is interme- diate between melanopterus and politiceps, but the differences are discrete. One distinctive feature of mexicanus is the very narrow malar space, as indi- cated by the MS/EH: 0.12-0.15 (the lowest malar space/eye height ratio for any member of the spe- cies-group). Also, the first metasomal tergite (Tl) is somewhat longer and narrower than in other members of Eucystomastax. ACKNOWLEDGEMENTS The following collections and curators provided loans of holotypes and access to other specimens upon which this study was based: ANSP The Academy of Natural Sciences, Philadel- phia, Pennsylvania (D. Azuma) BMNH The Natural History Museum, London (T. Huddleston) CNC Canadian National Collection, Ottawa (M. Sharkey) MCZ Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts (J.M. Carpenter) ZMHB Museum fur Naturkunde der Humboldt- Universitat, Berlin (F. Koch) TMB Termeszettudomanyi Miizeum Allattara (^Hungarian Natural History Museum), Budapest (J. Papp) USNM U.S. National Museum of Natural History, Washington, D.C. (P.M. Marsh) This research was supported by a 1 989 grant from the American Philosophical Society (research grant #00036 1 ) and by University of Wyoming Experiment Station Project #256-90. The Museum of Comparative Zoology (MCZ) collections and library resources were essential to this research, and the past and continuing support of that institution are gratefully acknowledged. In particu- lar, I would like to thank Muriel Conant, of the Museum of Comparative Zoology Library, for her assistance in locating the ancient Erichson tome, without which this project could not have been completed. Thanks are due to Katherine Brown-Wing (Harvard University) for pre- paring the color habitus illustration of Aleiodes melanopterus (Erichson) and Trisha Rice (Harvard Uni- versity) for her assistance with the scanning electron microscope. The manuscript was reviewed by Paul M. Marsh (SEL, USDA), David Wahl (American Entomo- logical Institute), and Mike Sharkey (Agriculture Canada), who provided many constructive comments. Also, I wish to thank Benedito Baptista dos Santos (Federal University of Goias, Goiania) for his kind assistance and access to his museum and laboratory during my 1992 visit to Brazil. LITERATURE CITED Achterberg, C. van. 1982. Notes on some type-species described by Fabricius of the subfamilies Braconinae, Rogadinae, Microgastrinae and Agathidinae (Hy- menoptera: Braconidae). Entomologische Berichten 42: 133-139. Achterberg. C. van. 1991. Revision of the genera of the Afrotropical and W. Palearctic Rogadinae Foerster Volume 2, Number 1, 1993 11 (Hymenoptera: Braconidae). Zoologische Verhandelingen 273: 1-102. Brues, C.T. 1912. Brazilian Ichneumonidae and Braconidae obtained by the Stanford Expedition. Annals of the Entomological Society of America 5: 193-229. Cameron. P. 1911. On the Hymenoptera of the Georgetown Museum. British Guiana. Timehri: The Journal of the Royal Agricultural and Commercial Society of British Guiana 1: 306-330. Cresson, E.T. 1869. List of the North American species of the genus Aleiodes Wesmael. Transactions of the American Entomological Socier\> 2: 377-382. Erichson, W.F. 1848. Insecten. Pp. 553-617 In: Schomburgk, R. Reisen in B lit i sell Guiana. Verlagsbuchhandlung von J.J. Weber, Leipzig. 1260 pp. Harris, R.A. 1979. A glossary of surface sculpturing. Occasional Papers in Entomology 28: 1-31. Marsh. P.M. 1989. Notes on Braconidae (Hymenoptera) associated with jojoba {Simmondsia chinensis) and descriptions of new species. Pan-Pacific Entomolo- gist 65: 58-67 . Marsh, P.M., S.R. Shaw & R.A. Wharton. 1987. An identification manual for the North American genera of the Family Braconidae (Hymenoptera). Memoirs of the Entomological Society ofWashington 13: 1 -98 . Shaw, M.R. 1983. On[e] evolution of endoparasitism: the biology of some genera of Rogadinae (Braconidae). Contributions of the American Ento- mological Institute 20: 307-328. Shaw, M.R. & T. Huddleston. 1991. Classification and biology of braconid wasps. Handbooks for the Iden- tification of British Insects 7: 1-126. Shenefelt, R.D. 1969. Redescription of Macrostomion bicolor Szepligeti (Hymenoptera: Braconidae: Rogadinae). Proceedings of the Entomological Soci- ety of Washington 71: 44 1 . Shenefelt. R.D. 1975. Braconidae 8: Exothecinae, Rogadinae. Pp. 1115-1262, In: van der Vecht & Shenefelt. R.D. [eds.], Hymenopterorum Catalogus [new edition), W. Junk B.V., 's-Gravenhage. Szepligeti. V. von. 1 900. Braconiden aus Neu-Guinea in der sammlung des Ungarischen National-Museums. Termeszetr Fuzetek 23: 49-65. Szepligeti. V. von. 1904. Sudamerikanische Braconiden. Annates Musei Nationales Hungarici 2: 173-197. Szepligeti, V. von ( 1 906 ) Braconiden aus der Sammlung des Ungarishen National-Museums. I. Annates Musei Nationales Hungarici 4: 547-618. Whitfield, J.B. 1988. Revision of the Nearctic species of the genus Stiropius Cameron ( =BucculatriplexAuct. ) with the description of a new related genus (Hy- menoptera: Braconidae). Systematic Entomology 13: 373-385. J. HYM. RES. 2(1), 1993 pp. 13-83 The Evolutionary Ecology of Symbiotic Ant - Plant Relationships Diane W. Davidson and Doyle McKey (DWD) Department of Biology, University of Utah, Salt Lake City, Utah 841 12; (DM) Department of Biology, University of Miami, Coral Gables. Florida 33124 Abstract. — A tubular survey of ant-plant symbioses worldwide summarizes aspects of the evolutionary ecology of these associations. Remarkable similarities between ant-plant symbioses in disjunct tropical regions result from convergent and parallel evolution of similarly preadapted ants and plants. Competition among ants has driven evolutionary specialization in plant-ants and is the principal factor accounting for parallelism and convergence. As habitat specialization accompanied the evolutionary radiation of many myrmecophytes, frequent host shifts and de novo colonizations by habitat-specific ants both inhibited species-specific coevolution and co-cladogenesis. and magnified the diversity of mutualistic partners. The comparatively high species diversity of neotropical plant-ants and myrmecophytes probably results from two historical factors. Most importantly, influenced by Andean orogeny, greater habitat disturbance by fluvial systems has created a mosaic of habitat types unparalleled in other tropical regions; both myrmecophytes and plant- ants have diversified across habitat boundaries. Second, the arrival of a new wave of dominant ants (especially Crematogaster) may have condensed the diversity of relatively timid plant-ants to a greater degree in Africa and Asia than in the more isolated Neotropics. Regular trajectories in the evolutionary histories of plant-ants appear to be driven principally by competition, in a manner analogous to the taxon cycles or pulses proposed for other groups. "In all the plants I have seen bearing sacs on the leaves, to whatever order they belong, it is remarkable that the pubescence consists of long hairs having a tubercular base; and although I do not see what connection that peculiarity can have with the ants' choice of a habitation, it is probable they find some advantage in it." .... "Ants' nests in swellings of the branches are found chiefly in soft-wooded trees of humble growth, which have verticillate or quasi- verticillate branches and leaves, and especially where the branches put forth at the extremity a whorl or fascicle of three or more ramuli; then, either at each leaf-node or at least at the apex of the penultimate (and sometimes of the ultimate) branches, will probably be found an ant-house, in the shape of a hollow swelling of the branch..." (Spruce 1908). INTRODUCTION in historical and ecological factors shaping the evolution of mutualism. Complicating this en- A synthetic overview of the evolutionary ecol- deavor still further is that most studies of mutualism ogy of mutualism has been disappointingly slow to focus on pollination and dispersal systems, which develop (Bronstein 1991). In large part, this short- account for 80 % of the articles on mutualism in coming may reflect the composite nature of Bronstein's( 1991 (survey. Despite excellent treat- mutualisms, which often arise as parasitisms (Th- ments available fortaxonomically and/or geographi- ompson 1982), and frequently convey benefits con- cauy restricted suites of such interactions (e.g., tingent on physical environments, population den- Heithausetal. 1975,FeinsingerandColwell 1978, sities, and third or multi-species interactions (re- Janson 1983, Herrera 1984, Gautier-Hion et al. viewed in Howe 1984. Addicott 1985, Law and 1985, Moermond and Denslow 1985, Gottsberger Koptur 1 986, Schemske and Horvitz 1988, Thomp- 1990, Bronstein 1992). both the overwhelming son 1988, Cushman and Addicott 1991 ). The lack numbers and the taxonomic and ecological diver- of a conceptual organization for such complex and sity of these interactions magnify the difficulty of variable associations inhibits a search for patterns 14 Journal of Hymenoptera Research identifying single or few organizing processes or principles. Symbiotic associations between ants and myrmecophytic plants offer a useful counterpoint. Sufficiently small in number to be summarized in a single table (Appendix 1 ), they nevertheless occur in numbers adequate to provide fertile substrate for hypothesis testing. Their presence in tropical re- gions throughout the world facilitates comparisons among taxonomic and ecological equivalents evolved in isolation on different continents (McKey and Davidson, in press). Despite their considerable diversity and widespread distribution, these rela- tionships are relatively uniform in structure. Thus all myrmecophytic plants provide permanent hous- ing and food to ants which are known or (more often) presumed to protect their hosts from her- bivory or competition, or to provision them with nutrients (reviewed recently in Beattie 1 985, Huxley 1986,Jolivet 1986, Holldobler and Wilson 1990). Here we provide an overview of the symbiotic ant-plant relationships, focusing principally on trees, shrubs and hemiepiphytes of the American and African tropics. (The epiphytic ant-plants have been reviewed recently elsewhere by Davidson and Epstein 1989.) This geographic specialization re- flects our comparatively poor understanding of ant- plant relationships in the Oriental and Australian tropics where, with the exception of ant-epiphytes ( Jebb 1 985, Huxley and Jebb 1 99 1 ), investigations are fewer in number and less detailed (but see the recent proliferation of work by Fiala and Maschwitz 1990 and 1991, Fiala et al. 1989 and 1991, Maschwitz et al. 1989 and 1991). For myrmecophytes overall, existing evidence is often too meagre for a convincing assessment of the fitness consequences of particular associations. We therefore avoid using the terms "mutualism" and "facilitation" in favor of less restrictive words like "association", "interaction", or "relationship". For similar reasons, the terms "myrmecophyte", "myrmecophytic" and "ant-plant" are used here only to describe plants regularly inhabited by ants, without implying that plants either benefit from the ants or possess traits evolved principally as ant attractants. On occasion, we also refer to "myrmecophilic" plants, those which are not sym- biotic with ants but produce obvious ant attractants such as extrafloral nectaries (EFN's) and/or pearl bodies. Our principal themes here are the factors which have predisposed particular ants and plants toward symbiotic association, and the ecological forces which have driven evolutionary specialization in each of these taxa. We also summarize the pro- cesses generating and maintaining diversity within each of these groups, as well as the factors limiting species specificity and co-cladogenesis. Finally, we speculate about particular evolutionary trajec- tories which appear to have occurred regularly across independent lineages of plant-ants and ant- plants. As a prelude to all the above, we briefly review the way in which historical context appears to have influenced the evolution of ant-plant sym- bioses in the American and African tropics. DIVERSITY, BIOGEOGRAPHY AND HISTORY Both plant-ants and myrmecophytes achieve their greatest richness in the American tropics ( McKey and Davidson, in press). Among ants, the proportion of neotropical and African genera con- taining specialized plant-ants is approximately the same, whether calculated by biogeographic region (respectively, 10 % and 12 % of genera) or for mesic tropical environments (12.8 % and 14.5 %, respectively). Although the mesic Neotropics hold approximately 1 .3 times as many ant genera as does mesic tropical Africa (Brown 1973), the latter land mass has slightly more genera which contain at least one plant-ant. Nevertheless, two of these gen- era are monotypic and, based on present knowl- edge, the species richness of plant-ants appears to be about 3.5-fold greater in the Neotropics than in Africa (current estimates of 85 species versus 24, including one species in Madagascar). Differences in diversity occur principally due to the prolifera- tion of plant-ant species within endemic neotropical genera. In the New World, significant radiations of plant-ants occur in endemic Pseudomyrmex (N = 32 species), Azteca (N probably > 20), Myrmelachista (N > 6), and Allamenis (N 8), as well as in cosmopolitan Pheidole (N 6) and Pochycondyla (N 4). In contrast, significant radiations of African plant-ants are limited to Tetraponera (N 5) and Technomyrmex (N 6), Volume 2, Number 1, 1993 15 both widely distributed in the Old World tropics, and even these radiations are comparatively small. Relative to the ant faunas of both the American and African tropics, those of the Oriental and Aus- tralian regions appear to be poor in plant-ant genera ( McKey and Davidson, in press); respectively, only 5.6 % and 7.3 % of regional ant genera, and 7.3 % and 9.1 % of mesic tropical genera, contain plant- ants. Moderate to large radiations of plant-ants in the Oriental region include only cosmopolitan Crematogaster(N 8 species) and Camponotus (N 7), as well as endemic Cladomyrma (N 5), and current estimates of plant-ants are only 24 species overall. In the Australian region, encompassing northern Australia, New Guinea and associated islands, such radiations are limited to endemic Anonychomyrma (probably > 3 species), and the species richness of plant-ants presently stands now at only about 1 2 species. Although the numbers of plant-ants may increase slightly in these regions due to increased sampling effort (cf. Dorow and Maschwitz 1 990, Maschwitz et al. 1 99 1 ) and taxo- nomic revision (e.g., S.Shattuck. 1991, 1992b), the relative poverty of plant-ants at the generic level is likely real. Myrmecophytes probably constitute a similar fraction of all plant genera in the American and African tropics, but their species richness is dis- tinctly greater in the Neotropics (McKey and Davidson, in press). Again unmatched in Africa, major radiations of ant-plants within (mainly) en- demic, neotropical genera largely account for this difference. Neotropical plant genera with signifi- cant radiations of myrmecophytes include endemic Cecropia (N 50-60 ant-plant species), Tachigali (N 20), Triplaris (N = 17), Tococa (N = 40-45), Clidemia (N = 1 5-20) and Maieta (N 1 5 ). as well as non-endemic Acacia (N 12 species), OcoteaiN 6) and Hirtella(N = 6). In contrast, in Africa only Acacia (N 15) and, to a lesser extent, Cuviera (N = 8+), Canthium (N = 3-6) and Clerodendrum (N 3) contain moderate to large numbers of ant- plants, and of these genera only Cuviera is re- stricted to the Ethiopian region. Estimates of myrmecophyte species richness are about three- fold greater in the American than the African trop- ics, and maximum local (alpha) diversity may be twice as high. Although it is not yet possible to estimate the frequency of myrmecophytes in the tropical floras of Oriental and Australian regions, substantial radiations of myrmecophytes within genera are comparatively limited (references in McKey and Davidson [in press]). These probably include only Macaranga (N 23), Korthalsia (N = 7+) and Neonauclea (N = 4+) in the Oriental tropics, and Chisocheton (N = 6). Kibara, Steganthera, and Semecarpus (each with N = 4) in the Australian tropics. Altogether, the Oriental and Australian tropics likely hold slightly more than 100 myrmecophyte species. At the generic level, the determinants of ant- plant and plant-ant diversity in the American and African tropics are probably similar to those regu- lating species richness of the floras and ant faunas overall (McKey and Davidson, in press). Radia- tions of myrmecophytes and plant-ants in both areas appear to have been strongly affected by both the climatic and geologic histories of the continents and to have been correlated with diversification in habitat use. As may be common for neotropical plants in general (Gentry 1986, 1989 and in press, but see Simpson and Todzia [1990] for the high Andean flora), generic radiations of ant-plants may often be comprised of neoendemics with compara- tively recent origins. Frequently geographically or edaphically restricted, such species may be prod- ucts of a "species pump", postulated to have gener- ated new species through habitat specialization during range reexpansions within interglacial inter- vals of the Pleistocene (Colinvaux, in press). Al- though the diversity of tropical ant species has not previously been related explicitly to any similar mechanism, a possible link between speciation and habitat specialization is evidenced by the observa- tion that many plant-ants show greater specificity to habitats than to host species (Benson 1985, Davidson etal. 1 989 and 1991; Longino 1989a and 1991a). Given historical and contemporary differences in geological activity, and in correlated rates of habitat disturbance on the two continents, the Ameri- can tropics should have provided greater opportu- nity than did tropical Africa for habitat specializa- tion and speciation (McKey and Davidson, in press). Topographically, the mesic African tropics occupy a comparatively flat and featureless plain, much 16 Journal of Hymenoptera Research more homogeneous than mesic tropical America. In the Neotropics, orogenic activity in the Andes has not only influenced the montane and submontane areas directly, but has given rise to the fluvial disturbances that helped to create a spectacular mosaic of landscapes over the vast Amazonian region. No less than 26 % of modern lowland forests of Western Amazonia give evidence of recent erosional and depositional activity, and ap- proximately 12 % of these lands are currently in some stage of succession ( Salo et al. 1 986, Rasanen etal. 1987). In addition to their role in creating and maintaining a landscape mosaic conducive to rapid speciation, the Andes also appear to have protected the mesic Neotropics from the severe and frequent droughts which could have magnified species ex- tinctions in Africa, as mesic forests were repeatedly reduced and fragmented during Pleistocene times (Raven and Axelrod 1974, Axelrod and Raven 1978). Finally, neotropical species should also have received greater protection than their African coun- terparts from Pleistocene temperature variation. Lowland Africa is approximately 500m higher in elevation than is lowland Amazonia, and would have provided fewer refugia for plants and animals during glacial periods. Current evidence (e.g., Bengo and Maley [1991]) indicates that montane forest, including elements now restricted to the cool, moist conditions of the Afromontane zone, extended to low elevations (600 m or perhaps lower) in Central Africa during several periods over the last 135,000 years. Judging from the dramatic drop in ant diversity and abundance with elevation on humid tropical mountains (Janzen 1973), the conditions suggested for these periods would not have been conducive to the success of much of the contemporary ant fauna of lowland African forests. To the extent that climatic fluctua- tions in Africa exceeded those in the American tropics, these could have led to the dissolution of mutualisms, even without species extinctions, as the fitness consequences of association shifted (e.g., to parasitism) with fluctuations in the abiotic and biotic environments. SIMILARITIES BETWEEN ANT-PLANT RELATIONSHIPS OF DIFFERENT TROPICAL REGIONS In the context of the aforementioned differences in species richness, and in the climatic and geologic histories of ant-plants on different tropical land masses, certain similarities in the form and ecology of ant-plant relationships of different continents appear all the more striking. For example, across tropical land masses, large colonies of active and aggressive ants occupy fast-growing and light- demanding pioneer trees (neotropical Cecropia and Old World Macaranga). In contrast, timid ants inhabit small, slow-growing understory shrubs or treelets with hairy domatia (e.g., American Hirtella, Duroia, and many melastomes, and African Magnistipula, Delpydora, Cola, and Scapho- petalum). Finally, myrmecophytic trees of second- ary forests and forest light gaps ( neotropical Triplaris and African Bartend) grow in circular clearings made by pseudomyrmecine ants, which attack veg- etation in the neighborhood of their hosts. McKey and Davidson (in press) have amassed evidence against common ancestry as a general explanation for these remarkable commonalities. While some comparisons between Africa and Asia suggest com- mon descent of ant-plants, plant-ants or both, myrmecophytes and specialized plant-ants appear to have evolved largely independently in America and Africa. No ant-plants of Africa and the Neotropics have apparently shared a myrmecophytic common ancestor. In contrast, the plant-ant habit may be ancient in the sub- family Pseudomyrmecinae and in tribes Myrmelachistini and Tapinomini, and might possibly have preceded the splitting of South America and Africa. However, with these possible exceptions, resemblances between symbiotic asso- ciations in the American and African tropics are not due to common descent of one or both partners from an association that predated continental separation or other vicariance events, or which migrated intact from one continent to the other (McKey and Davidson, in press). The remarkable correspondences between ant- plant associations in the American and African tropics must therefore be due to some combination of: ( 1 ) parallel evolution of ants and/or plants from Volume 2, Number 1, 1993 17 similar starting material, (2) evolutionary conver- gence, and (3) the matching of symbiotic partners according to a set of shared rules. The task then is to identify the preadaptations which have been pressed into service and evolutionarily modified in symbiotic ants and plants, and to recognize the selection pressures which have led repeatedly to the correspondences noted above. PREADAPTATIONS OF PLANTS AND ANTS Parallel and convergent evolution are usually regarded as evidence that selection pressures have acted in similar ways on organisms of different lineages. Selection, however, is only part of the explanation for these phenomena. Different lin- eages may follow similar evolutionary trajectories because they share similar developmental con- straints which channel the action of selection along a limited number of paths. Preadaptations for Myrmecophytism The evolutionary antecedents of specialized myrmecophytic traits are poorly explored. How- ever, comparative studies of myrmecophytes and their less specialized relatives are begining to sug- gest plausible and testable hypotheses about the origins of these traits (Benson 1985, McKey 1989 and 1991, CTDowd and Willson 1989, Fiala and Maschwitz 1991, Schupp and Feener 1991). For example, in various plant taxa. a few similar struc- tures have repeatedly provided the raw materials transformed by selection into myrmecophytic struc- tures. An understanding of the origins of these traits may help to identify constraints which have pressed ant-plants of diverse lineages and biogeo- graphic regions into a limited number of molds. It may also indicate developmental patterns which have facilitated the evolution of myrmecophytism, and suggest why myrmecophytes have evolved repeatedly in some lineages, but rarely or never in others. Provision of Food for Plants. — Discussion of the evolutionary background of myrmecophytes has tended to emphasize the provision of food for ants. Indeed, there is evidence from many lineages that the ancestors of ant-plants possessed extrafloral nectaries, pearl bodies, or other traits, which pro- vided food for ants in loose non-symbiotic interac- tions. The large, complex nectary glands of some ant-plants (e.g.. Acacia, Endospermwn, and some Macaranga), and the elaborate food bodies of oth- ers (e.g., Mlillerian bodies of Cecropia, and Beccarian bodies of Asian Macaranga) are readily accounted for as outgrowths of these traits. As ant- plant interactions intensified into symbiosis, such attributes should have been easily modified by selection acting on the composition and rate of supply of food for ants. The Beltian bodies of Central American ant-acacias may be the only case in which a specialized food-producing structure of a myrmecophyte lacks an obvious antecedent among unspecialized but related plants. Provision of food ensures that ants are a regular component of the plant's biotic environment, and doubtless facilitates the evolution of more intense interactions. However, myrmecophytes have evolved in only a small subset of the numerous plant lineages whose members are engaged in op- portunistic myrmecophilic interactions; otherplant traits must also play a role in facilitating or con- straining the evolution of symbiotic interactions. Furthermore, in many cases, neither the myrmecophytes nor their close relatives provide food directly to ants. In many cases, EFN's and food bodies are lacking, and scale insects (Coccoidea, Homoptera) are a major source of colony nutrition (Appendix 1). Following Ward ( 1991 ), we suggest that many myrmecophytic rela- tionships evolved not from pre-existing myrmecophilic relations, but from parasitisms in which stem-nesting ants began to inhabit live plant cavities and to tend Coccoidea. Structures for Housing Ants. — We must thus explore plant traits that facilitated the production of cavities that could be modified by selection into specialized structures for housing ants. The evolu- tionary antecedents of myrmecodomatia, the defin- ing feature of specialized myrmecophytes, have received little attention. Preadaptations and devel- opmental constraints in the evolution of myrmecodomatia will be discussed in detail else- where (McKey, in preparation) and are summa- rized only briefly here. 18 Journal of Hymenoptera Research Table 1 Taxa in which at least some myrmecophytes have long, dense hairs which inhibit insect movements on stems, domatia or both. Region Family Genus ETHIOPIAN Chrysobalanaceae Magnistipula Dichapetalaceae Dichapetalum Ebenaceae Diospyros Rubiaceae Canthium Cuviera Sapotaceae Delpydora Sterculiaceae Cola Scaphopetalwn NEOTROPICAL Boraginaceae Cordia Chrysobalanaceae Hirtella Fabaceae Platymisciwn Tachigali Gesneriaceae Besleria ■ Melastomataceae Allomaietcr Blakea3 Clidemia Conostegia Henriettea Maieta Sagraea6 Tococa7 Cecropiaceae Pourouma Polygonaceae Triplaris Rubiaceae Duroia8 Hojfmannia Remijia ORIENTAL Melastomataceae Medinilla Verbenaceae Callicarpa Piperaceae Piper AUSTRALIAN Monimiaceae Steganthera At least one species, collected from a hillside over the junction of the Rio Sotileja and the Rio Manu, in southeastern Peru (D. Davidson, unpublished). Closely related to Maieta (A. Gentry, personal communication) Benson ( 1 985 ) considers the leaf pouches of B. formicaria to be in transition from acarodomatia to ant-domatia. Among the melastomes listed here, Blakea is unique in not belonging to the Miconieae. At least three independent origins of domatia in Clidemia sensu strictu; includes Myrmidone (Judd and Skean 1991 ) Includes Henrieltella (Judd 1989) Includes Ossaea p.p. (Judd 1989) Includes Microphysca (Judd and Skean 1991 ) Two independent origins of domatia (foliar domatia and swollen intemodes) Volume 2, Number 1, 1993 19 Fig. 1. Paired leaf-pouch domatia, covered with dense, erect trichomes. at the base of a leaf of Delpydora macrophylla Pierre (Sapotaceae) in southern Cameroon. These pouches are formed by downward folding and rolling of the expanded base of the blade on either side of the midrib. The domatia are usually occupied by timid Technomyrmex species. Stipules have been modified into ant-domatia in a few myrmecophytes: known examples are all from the Old World tropics (Appendix 1). (The only apparent exception is Acacia, in which thorns, themselves highly specialized stipules, have been modified into domatia in both neotropical and Old- World representatives.) In many tropical plants, large stipules function as mechanical protection for the growing bud. In some cases, stipules possess ant-attractive structures which provide biotic de- fense as well. Where stipules are persistent, rather than being shed soon after maturation of associated nodes, ants may find suitable shelter for tending homopterans, nesting, or both. Although ants and their associated debris are observed frequently be- neath large stipules, only rarely have these stipules become evolutionarily modified to house ants. Specializations include recurving or inflating of the stipule to form a more enclosed structure (as in New Guinea Psychotria and perhaps African Dacty- ladenia), location of specialized food bodies on the lower surface of the stipule (Asian Macaranga), and possibly the evolution of persistent stipules. In an analogous case, African Diospyros conocarpa GLirke & K. Schumann has specialized, hairy domatia formed from persistent cataphylls (Letouzey and White 1970). These structures are leaf-like appendages, usually rapidly deciduous, and formed on the first few nodes of young expand- ing twigs in many tropical trees with rhythmic growth patterns (Halle et al. 1978). They are func- tionally analogous to stipules. In D. conocarpa, the cataphylls are folded to form a structure completely enclosed, except for a small opening near the base of the blade, and they are persistent, rather than deciduous, as in related species. These structures 20 Journal of Hymenoptera Research are occupied by Technomyrmexkohlii ( Forel), which also inhabits several leaf-pouch ant-plants in the same forests. In Asia, Africa, and the Neotropics, leaf-pouch domatia of strikingly similar form have evolved in numerous myrmecophyte lineages (Appendix 1). Formed near the leaf base, and typically paired on either side of the midrib (but single in some spe- cies), they are usually covered with long, dense trichomes (Table 1). Restricted to understory treelets and shrubs, these ant-plants typically are occupied by small, timid ants. Leaf-pouches seem to be formed in one of two ways. In some taxa (e.g., neotropical Melastomataceae, and African Sterculiaceae), invagination occurs in the internal portion of the leaf blade, in a region flanking the base of the midrib. This invagination produces single or paired inflated pouches, each with an entrance on the abaxial leaf surface. In at least four plant families, including most frequently and vari- ably in the Rubiaceae, paired leaf pouches form in a different manner. At the bases of leaf blades, (revolute) leaf margins curl downward, as in Afri- can Delpydora (Fig. 1), Magnistipula, Dichape- talum gassitae Bret., and Ixora hippoporifera Bremek., neotropical Hirtella and Remijia, and Asian Callicarpa saccata Steen. Less frequently, (involute) leaf margins curl upward, as in neotropical Duroia saccifera Benth. and Hook. Pouches may be bubble-like invaginations (Gardenia imperialis L. Pauwels) or, more often, scroll-like hollow tubes. It has long been postulated that the leaf-pouch domatia of ant-plants evolved from acarodomatia (Schnell 1966, Schnell et al. 1968), presumably by intermediate stages in which domatia could be occupied either by mites or by small ants. Selection led to increased size of domatia with progressive transference of protective function from mites to ants (O'Dowd and Willson 1989). Benson (1985) also argues that leaf-pouch domatia evolved in myrmecophytes from small depressions in leaf surfaces. The original function of these depres- sions was to shelter ant-tended homopterans. The two hypotheses are not mutually exclusive, as ants may also have used acarodomatia to shelter ho- mopterans (Benson 1985). Hypotheses implicat- ing acarodomatia in the origin of leaf-pouch ant- domatia receive strong support from cases like Cola marsupium K. Schumann, in which a single leaf presents a graded series of domatia increasing in size from typical acarodomatia at the leaf apex to large inflated pouches at the leaf base (Schnell and Beaufort 1966). Why have leaf-pouch domatia evolved repeat- edly in certain groups, for example, at least nine times in the tribe Miconieae in the Melastomataceae (Table 1)? Leaves of many Miconieae have strongly arcuate venation with sections of the leaf blade vaulted and curved upward between major veins. Even before selection intervened to enlarge these structures, this waffle-like leaf organization may have fortuitously provided invaginations large enough to shelter ant nests. In African Sterculiaceae, where similar domatia have evolved twice, vena- tion is also palmate, with three large veins converg- ing at the leaf base. The largest group of myrmecophytes is that in which domatia are located in stems, or in stem-like structures such as petioles or inflorescence stalks (Appendix 1). Increasing evidence supports the hypothesis that ants originally colonized cavities created in twigs and petioles by wood-boring in- sects (Ward 1991, also Appendix 1). Together with cavities formed by spontaneous drying of pith ca- nals, these cavities provided ants with shelter and substrate for brood and symbiotic Coccoidea. When the presence of ants conferred net benefit (e.g., by protection against phytophagous insects, including wood-borers, and any diseases transmitted by these insects), selection acted on the plant to evolve features facilitating its occupancy by ants (Ward 1991). Such traits include specialized swollen twigs and a prostoma, or relatively unlignified spot through which ants gain easy access to the domatia. What traits may have predisposed plants to evolve symbiotic association with ants via this mechanism? Wood-boring insects usually attack soft, pithy portions of stems. The larger the primary diameter of a stem, the thicker its pithy central section. Thus thick-twigged plants offer greater opportunities than do thin-twigged taxa for wood- boring insects, and for ants which nest secondarily or primarily in the cavities of living plants. Al- though much poorly understood interspecific varia- tion in stem structure affects the relationship be- Volume 2, Number 1, 1993 21 tween the primary diameters and pith diameters of twigs, myrmecophytes are most likely to evolve in plants with thick twigs. This observation gains importance when we consider the plant-architectural correlates of stem primary diameter. The best known of "Corner's rules," and one confirmed by quantitative studies (White 1983), states that there is a positive correla- tion between the primary diameter of a stem axis and the size of appendages (e.g., leaves) borne by it (Halle et al. 1978). This correlation means that selection acting on leaf size (Givnish 1987) also drives evolutionary change in stem diameter (McKey 1991 ). Thus, the evolution of stem domatia may be facilitated by an evolutionary increase in leaf size, driven for example, by climatic change, by range extension into more mesic environments (Givnish 1987), or by selection to minimize meta- bolic cost of woody leaf-support tissues (White 1983). If disparities in leaf size were related to habitat, myrmecophyte frequencies could be corre- lated with habitat, independently of and perhaps even despite any habitat-related differences in se- lection imposed by symbiotic ants ( McKey, unpub- lished). Corner's Rule may help account for several groups of ant-plants with domatia in thickened support structures (Appendix 1). First, myrmeco- phytism has evolved often in genera whose moist, shaded, understory environments have favored com- paratively large, broad leaves and thick stems (e.g., African Leonardoxa, and Oriental or Australian Tapeinosperma, Steganthera, Kibara, and Myristica). Ants also live symbiotically with mem- bers of the Meliaceae, Sapindaceae, and Anacardiaceae, whose leaves are not only large, but compound. In the Meliaceae, myrmecophytes ap- pear to have evolved independently in four genera, including three Asian taxa {Aphanamixis, Chisocheton an&Aglaia) with massive stems sup- porting large compound leaves. Even within Aphanamixis, myrmecophily characterizes forms with relatively large leaves and twigs (Mabberley 1985). Second, thick support structures for large leaves may also have facilitated the frequent evolu- tion of ant-plants in fast-growing pioneer trees, whose large leaves and sparse branching allow them to support a considerable leaf surface area with minimum investment in woody framework (White 1983). Examples are neotropical Cecropia, Asian Macaranga and Australian Eudospermum, which almost surely converged due to selection on leaf size and tree architecture prior to the evolution of myrmecophytism. Other myrmecophytic pio- neers of riverine and forest light gaps include neotropical Triplaris, Australian Nauclea and Afri- can Barteria and Vitex grandifolia Giirke. In all of the plants in these two categories, ant protection might be especially advantageous, because the large and parenchyma-rich meristems are especially sus- ceptible to damage by wood-boring insects. Since most of these plants produce one-to-few large mer- istems at any one time, the material and opportunity costs of losing even one meristem could be very high. Finally, two smaller groups of ant-plants house ants in either false nodes, thickened to support multiple leaves (e.g., two Cordia species and Duroia hirsute. Poepp. and Endl.), or in stout petioles (Piper, Pourouma and Tachigali). Although peti- oles might often be too short-lived to function as domatia, they are likely to be comparatively long- lived for both the compound leaves of Tachigali and the simple leaves of myrmecophytic under- story Piper species (in which ant cavities also extend into the stem itself). Preadaptations and Pathways to Specialization in Ants Specialized plant-ants are represented dispro- portionately in particular taxonomic categories of ants, and shared characteristics of these taxa pro- vide evidence of factors predisposing ants to evolve symbiotic relationships with plants. Worldwide, plant-ants have evolved in five of 12 subfamilies in the Formicidae (Appendix 1). They are absent only from subfamilies of specialized legionary and other predatory ants (Cerapachyinae, Dorylinae, Ecitoninae, Leptanillinae, and Myrmeciinae), and from the monotypic Aneuretinae and Nothomy- rmeciinae. Until recently, they were also deemed absent from the Ponerinae, the most predatory of five subfamilies containing at least some species that depend directly and substantially on plant resources. However, at least four species of 22 Journal of Hymenoptera Research Fig. 2. Leaves bound together with carton to form the ephemeral nests of Dolichoderus (= Hypoclinea) bidens (L. in southeastern Peru. Pachycondyla now appear to be specialized sym- bionts of Cecropia (Davidson et al. 1 99 1 , Davidson and Fisher 1991, J. Longino, personal communica- tion). Still, plant-ants are poorly represented in the Ponerinae and among predatory ants in general. The evolution of obligate plant-ants in five sub- families, approximately 30 genera (Appendix 1), and multiple clades of at least Pseudomyrmex (Ward 1991) and Azteca (Benson 1985, Longino 1991a and b) confirms the frequency and facility with which plant-ants have evolved, and provides abun- dant opportunity to find commonalities in lifestyles and traits that may have promoted evolutionary specialization on plants. For example, three of the six principal generic radiations of South American endemics have arisen (one each) in the sub-family Pseudomyrmecinae, and in the tribes Tapinomini (Dolichoderinae) and Myrmelachistini (Formi- cinae). These ants share the habit of regularly tending homopterans inside (all three taxa) or out- side (especially tapinomines) of cavities in live plants. Within each of these groups, common ancestors of contemporary plant-ants likely had additional traits which predisposed them to evolve symbiotic (parasitic as well as mutualistic) associa- tions with homoptera and plants. Because the relative competitive abilities of ants form an impor- tant part of the story, we turn now to consider various ecological differences among ants with different competitive abilities. Competitive Dominants. — Ecological limita- tions on populations of arboreal ants in lowland tropical forests add insight into probable origins, correlates and consequences of arboreal nesting habits, including stem-nesting. Colony popula- tions appear to be limited principally by food and nest sites (Wilson 1959b, Carroll 1979, Davidson and Epstein 1989). Because most arboreal ants are generalized foragers of plant and homopteran exu- dates, and of carrion, interspecific food require- ments are strongly overlapping, and competition can be intense. The competitive dominants of each tropical biogeographic region are species which have evolved means of nesting in areas of abundant food. They include Old World Oecophylla, Crematogaster, Tetramorium, Philidris and Polyrachis, some Australian Anonychomyrma, and New World Crematogaster, Camponotus, Azteca and Dolichoderus (including Hypoclinea. Shattuck, 1 992a). These ants either bind leaves together into Volume 2, Number 1 , 1 993 23 temporary nests, or construct potentially more per- manent carton homes in the canopy where food is abundant (Fig. 2). Like species which occupy the top of the competitive hierarchy at high temperate latitudes (Vepsalainen and Pisarski 1982), these species defend not only their nest sites and tempo- rary, localized food patches, but their entire forag- ing areas, as absolute territories. Although a certain threshold of aggressiveness may have been re- quired before these ants could defend their some- what exposed nests successfully against vertebrate enemies (e.g., monkeys and woodpeckers; J. Longino, personal communication), an eventual capacity to nest near abundant food almost cer- tainly contributed to the escalation of aggressive- ness and dominance. Most competitive dominants tend populations of Homoptera, whose exudates form a steady and predictable source of colony nutrition and help to fund high worker activity and aggression. These ants lack functional stings, but all possess elaborate chemical weaponry (Blum and Hermann 1978, Attygalle and Morgan 1984, Buschinger and Maschwitz 1984, Merlin etal. 1992). Expended in use, these exocrine products should be character- ized by more rapid turnover and greater cost than is associated with longer-lived stings and sturdy ex- oskeletons. Nevertheless, if chemical defenses are supported by the requisite resource base, they ap- pear to be more effective than stings in contests among ants (Davidson etal. 1988). With their rich sources of homopteran exudates, dominants should often experience an excess of dietary carbon in relation to protein, so that colony expansion is protein-limited. If so, this could explain the "high tempo" lifestyle (sensu Oster and Wilson 1978) characteristic of these ants and help to resolve the enigma of their seeming "inefficiency" in foraging (Oster and Wilson 1978; Holldobler and Wilson 1990). By spending relatively "cheap" carbon resources on aggression and seemingly extravagant levels of activity, these ants secure dominance over territories whose protein resources fund colony growth. Chemical weaponry and high activity levels are not the only traits determining dominance in these ants. Abundant food and freedom from nest site limitation appear also to have led to larger colony sizes and longer life expectancies. If the resource environments of ants have helped to shape the evolution of life history attributes (e.g., rates of egg-laying, worker turnover, etc.), a correlated evolved dependency on rapid rates of resource acquisition may restrict some dominants to the most productive sites in lowland rain forests (Davidson and Epstein 1989). Arboreal dominants are preeminent in monopolizing high quality re- sources at exposed sites such as EFN's, and Homoptera positioned on flowering and fruiting peduncles, where a plant's phloem resources are frequently most concentrated. As evidence of their competitive impact in one rainforest ant commu- nity as a whole, Wilson (1959b) noted that a num- ber of arboreal ant species regularly forage on the ground, whereas only a few exceptional ground nesters forage even in the low arboreal zone, and possibly none of these reaches the upper canopy. ( In the Neotropics, terrestrially nesting Paraponera and Ectatomma are obvious counter-examples, but both genera are exceptional among ponerines for their heavy reliance upon plant exudates, earned as large droplets in the mandibles.) Dominants can restrict the local diversity of other ants, as do the parabiotic associates of neotropical ant-gardens (Davidson 1988). Thus, the diversity of arboreal but not terrestrial ant species is lower inside the territories of Components femoratus Fab. and Crematogastercf. limata parabiotica (Forel), than in adjacent areas lacking these ants. Because the species composition and diversity of subordinate species often varies markedly with the identity of dominants, patchiness in the territories of domi- nants determines a mosaic of ant communities within many tropical forests (Leston 1973, re- viewed in Holldobler and Wilson 1990). Competitive dominance may be context depen- dent, e.g., differing in relation to the identities of plant species which form the substrate for ant nesting and foraging (Davidson and Epstein 1 989). Thus, host plant associations of Oecophylla longinoda (Latr.) (Dejean and Dijicto 1990) and Tetramoriumaculeatum (Mayr)(Dejeaneta\. 1992), two widespread dominants in African forests, are correlated with worker preferences for foliage types offered in laboratory experiments. 24 Journal of Hymenoptera Research Weak Competitors. — For competitively subor- dinate ants, the benefits of combining nesting and foraging locations are conditional on locating nests and resources in sites which are protected from invasion by dominants. Nests in dead or live twigs, stems, and larval insect borings can be defended if the cavity size is not much larger than the head diameters of workers, soldiers, or queens. By sealing a stem nest with her head, a single worker can protect her whole colony or colony fragment from invasion by enemy ants. Thus, along a Pacific Ocean beach at Corcovado National Park in Costa Rica, the many dead twigs of Coccoloba (Polygonaceae) trees were occupied by more than nine ant species (six of Pseudomyrmex alone), whose head widths were roughly equal and propor- tional to the internal diameters of their twig cavities (D. Davidson, personal observation). At least some African Tetraponera also appear not to nest in stems whose diameter exceeds a threshold value (TeiTon 1970). For small-bodied ants like the timid Wasmannia scrobifera Kempf in Costa Rica, other protected sites may include carton shelters beneath leaves of plants whose dense stem trichomes ex- clude larger bodied workers (see below). For comparatively docile and subordinate ants, the advantage of locating their resources inside stem cavities is clear. The evolutionary transition from nesting in dead twigs to nesting in live twigs and other cavities of live plants conveyed the addi- tional opportunity to obtain uncontested resources from phloem-feeding Homoptera (especially Coccoidea), which either invaded such cavities on their own or were brought there by the ants. More- over, nests in live wood were potentially habitable over much longer time periods than those in dead or decaying twigs and branches, obviating a need for frequent and dangerous nest moves. Longer tenure of living nest sites, which grew rather than decay- ing with time, may secondarily have allowed the evolution of larger colony sizes and increased op- portunities for local monopolization of resources, as well as the selective advantage of aggressive behavior and allelochemicals. Traits conferring a capacity to nest in live plants are not well studied, but they probably involve evolutionary adjustment to an increased threat from nest pathogens. Thus, Ward ( 1991 ) points out the tendency for hypertro- phy of metapleural glands in domatia-inhabiting pseudomyrmecines. Where studied, the function of metapleural secretions has been tied to the sup- pression of microbial pathogens (e.g., Maschwitz 1974, Holldobler and Engel-Siegel 1984). In summary, plant-ants are most frequent in taxa which depend directly or indirectly, but substan- tially, on plant resources. They are most likely to have evolved in competitively subordinate ants, selected to live in close proximity to food re- sources, but to nest and feed in comparatively protected and permanent sites which reduce dan- gerous contact with competitive dominants. Within this subset of ant taxa, selection for evolutionary specialization of plant-ants might have been less likely in groups where potent defensive exocrine compounds (e.g., many Dolichoderus species), and workerarmor or specialized diets (e.g., cephalotines) diminished the hazards of encounters with domi- nants. The transition from more generalized ancestors to specialized plant-ants would not have been dif- ficult. Founding queens should have evolved greater efficiencies in locating hosts that provided superior food or housing or were more easily accessed. By consuming or deterring insect herbivores, ants might then have enhanced their own fitness indirectly by promoting the vigor or prolonging the lifespans of their hosts. However, host specialization by ants, as well as consumption of eggs and larvae of insect herbivores, could have been favored in ants whether the ants and Homoptera had a net positive or nega- tive effect on these hosts. Longino (1987), for example, discusses the case of Leptothorax obtura- tor Wheeler, which nests only in cynipid galls of oaks and probably has no fitness effect on the host tree. Selection pressures on ants and plants should often have been asymmetric, leading to the expec- tation that ant-attractive traits would have evolved in only a subset of the host plants on which obligate plant-ants reside. Expectations based on this brief review of com- petitive interactions among arboreal ant species can now be compared with actual patterns in the distri- bution and ecology of specialized plant-ants. Volume 2, Number 1, 1993 25 THE MATCHING OF ANTS AND PLANTS Appendix 1 is a worldwide summary of all symbiotic ant-plant relationships known to us. To facilitate comparisons among ants of differing lifestyles and competitive abilities (see below), we organize the data by ant genus. Also evident in this summary is the basic asymmetry in the degree to which relationships are obligate for ants versus plants. The vast majority of the ants in the table are thought to be obligate plant-ants (column 7, though these are not necessarily host-specific). However, a substantial fraction of their host genera have no obvious myrmecophytic traits (column 6), despite their regular association with specialized (usually) or unspecialized ants (cf., African Musanga and Neotropical Tetrathylacium). Few plants with con- spicuous myrmecophytic traits (e.g., obvious domatia. or naturally hollow stems with prostomas) lack specialized plant-ants altogether, though some may occur principally with unspecialized ants in marginal habitats, or at the edges of their distribu- tions (see below). Almost certainly. Appendix 1 includes a mix of relationships in which ants are parasitic, commensalistic, or mutualistic with their hosts, and the net outcome of the interactions might even vary with habitat or ecological context. These outcomes are not wholly predictable from myrmecophytic traits, since even in mutualistic associations, plants need have no obvious specializations to attract ants. Clearly most of the relationships are poorly known, and many of the table entries are incomplete. Yet the table clarifies the types of data which will eventually be essential to describe pattern in these relationships, and we hope it will stimulate the collection of such data in future studies. Despite limited data, patterns in relationships of ants and host plants correspond roughly to those noted for tropical forest ant faunas as a whole. Across genera, the fastest growing myrmecophytes of disturbed forest edge (i.e., hosts with rapid rates of resource supply to ants) tend to be inhabited by ants from aggressive, dominant, carton-building genera (column 1 ), e.g., the Azteca of neotropical Cecropia, and Crematogaster of ecologically simi- larOld World (especially Asian) Macaranga. Less aggressive and competitively subordinate ant spe- cies tend to persist by employing one or more of several strategies likely to reduce interactions with the dominants. We deal with each of these in turn. Ant Pruning of Host-plant Neighbors The most common and significant natural en- emies of ants are other ants (Haskins 1 939). Species with sting defenses, usually inferior to chemical defenses in contests among ants, are disproportion- ately likely to attack and prune vegetation sur- rounding their hosts (Davidson et al. 1988, also column 4, Appendix 1 ). In both Africa and South America, this behavior is most widespread in pseudomyrmecine plant-ants, where pruning has evolved multiple times in independent lineages (Ward 1990). The potent stings of pseudomyrmecines may be an effective deterrent of vertebrates ( Janzen 1 972 ), but they are inferior to chemical defenses in repelling colonies of invading ants. Although the Pseudomyrmex of Triplaris and Acacia, and the Tetraponera of Barteria, do not forage extensively off their host plants, they regu- larly leave these hosts to sever the petioles of leaves on neighboring plants (Fig. 3). Eventually these neighbors die, leaving the host trees in starkly defined clearings within the forest. Such clearings have been hypothesized to re- ward resident colonies by enhancing host-plant vigor or, in drier environments, acting as natural fire breaks (Janzen 1967a). However, experimen- tal evidence suggests that a more immediate selec- tive advantage for attacks on neighboring vegeta- tion is the reduction of threats from more dominant arboreal ants. When permanent wire bridges were made between myrmecophytic Triplaris and neigh- boring trees, the frequency of invasions by domi- nant Crematogaster increased, and whole hosts or portions of these hosts were eventually usurped by Crematogaster or Azteca species (Davidson et al. 1988). The broad taxonomic distribution of obli- gate and facultative pruning behavior (the latter occurring only in the presence of enemy ants, Appendix 1, column 4) suggests that dominant competing and predatory ants constitute a major threat to many or most specialized plant-ants. Its prominence in neotropical ants is evidence against the hypothesis that a paucity of dominants charac- 26 Journal of Hymenoptera Research terizes that region (Carroll 1979, see also McKey and Davidson, in press). Presumably, pruning be- havior could also serve to defend resident colonies against invasions by leafcutter (Morawetz et al. 1 992 ) and legionary ants, which could devastate the resource base or the colony itself. Pruning behavior is not strictly limited to ants with functional stings (Appendix 1). Most neotropical Cecropia and Old World Macaranga and Endospermum establish in disturbed second growth vegetation, where vines are particularly abundant and troublesome to both plants and ants, and where weedy dominant ants are a constant threat (Benson 1985). Not surprisingly, the com- mon ant associates of these host genera (Azteca, Crematogaster and Camponotus, respectively ) will attack encircling vines (Appendix 1, Janzen 1969, Fiala et al. 1989; Davidson personal observation, Letourneau et al. 1993), though pruning is not typical for these genera as a whole. The compara- tively unbranched growth forms of these hosts may also help to limit contact with vines and neighbor- ing plants ( Putz and Holbrook 1988) and, therefore, with enemy ants (Benson 1985). In contrast to chemically defended ants, in which pruning is restricted to species inhabiting hosts of secondary forest, species defended principally by strong or weak stings (Pachycondyla, Tetraponera, Pseudomyrmex, and Allomerus) also tend to prune around hosts in primary forests, where threats from vines and dominant ants are not so severe. Not all plant-ants in these genera prune, but some species benefit from other forms of protection (see below). Worldwide, the most dramatic case of allelopa- thy by ants may be that of Myrmelachista (Formicinae) species inhabiting myrmecophytes in the intriguing western Amazonian "Supay chacras" (Quechua for "Gardens of the Devil"). Dominance of lowland forest stands (to > 10,000 m: in size) by multiple species of myrmecophytes, most promi- nently Duroia hirsuta [Poeppig and Endl.] K. Sclium., but also Cordia nodosa Lam. and Miconia nervosa Triana, suggests that the ants kill non- myrmecophytes selectively (Campbell etal. 1989). In a similar phenomenon, at somewhat higher el- evations of western Amazonia (700-1200 m), a different Myrmelachista species creates monospe- cific stands of myrmecophytic Tococa occidentalis Naudin (Morawetz et al. 1992). The two conge- neric ants share a similar behavioral ecology (D. Davidson, personal observation, for supay chacras, and Morawetz etal. 1992, for Tococa). Workers do not appear to forage off their hosts, but do leave their hosts to attack other plants. When seedlings or saplings of plants other than the host species are placed in the vicinities of these hosts, workers gnaw at the vascular bundles of leaves of the introduced plants, and can kill them in a matter of hours to days. Morawetz and colleagues describe the extraordi- nary capacity of these ants to single out especially vulnerable plant tissues for attack. Thus, workers bite and poison palmate leaves at the base of lami- nae, where all vascular bundles join, pinnately nerved leaves at nerve bases of the first and second order, and monocots (e.g., palms), nerve by nerve, along the entire leaf. Necrosis originating at the attack sites spreads rapidly over the entire lamina. Within a few hours to a few days, inhabitants of the Tococa can successfully kill seedlings and saplings within a radius of 4 m and damage trees up to 10 m in size. Light gaps created by ant activities are subsequently colonized by vegetative propagation of the host. Although Morawetz and colleagues discount the hypothesis that the killing of host plant neigh- bors by Myrmelachista has evolved principally to exclude enemy ants, several observations suggest that the hypothesis should not be ruled out. First, leaf-cutter ants, an important enemy of the Tococa, invade principally by contact with the branches of other plants, not via the main trunk. Second, no generalized arboricolous ants appear to forage within the territories of these specialized Myrmelachista. Furthermore, large worker forces may be needed to assure the safety of ants which have left their hosts. Attacks on neighbors of Tococa begin when the ant population of one or a few individual hosts is at least 1500 workers in size. Similarly within supay chacras, smaller fragments of the extended colo- nies show extreme fidelity to their individual hosts, and only workers of the largest trees leave their hosts to swarm over seedl ings and other vegetation . Moreover, the latter activities appear to be re- stricted to hot and sunny conditions (D. Davidson, personal observation), which may allow maximum worker activity and performance levels. To date. Volume 2, Number 1, 1993 27 Fig. 3. Pseudomyrmex dendroicus Forel on branches of neighboring plants, whose leaves have been pruned by the ants. The long, thin body shape of workers in Pseudomyrmex spp. may preclude their use of plants with long, dense trichomes. there have been no experimental tests of the effects of creating artificial and unseverable bridges be- tween neighboring intact trees and hosts of these Myrmelachista. Such experiments would greatly aid in assessing the evolutionary significance of the extraordinary behavior of these ants. Hiding among Trichomes The long, dense and erect trichomes on stems and domatia of many myrmecophytic plants form mechanical barriers to the movements of large- bodied ants and create safe havens for colonies of obligate plant-ants with timid and diminutive work- ers (Davidson etal. 1989; Fig. 4, Appendix 1). Ant- plants with inhibitory hairs on stems, domatia or both, occur in at least 18 neotropical genera (eight within Melastomataceae alone), and eight families, and appear to have evolved independently on at least 21 separate occasions (Table 1). In Africa, such hairy ant-plants occur in at least eight genera and six families, with each generic occurrence representing a single independent origin. Trichome- myrmecophytes have also evolved in at least four genera in the Oriental and Australian tropics (Table 1 ), though the symbiotic associates of these plants remain unknown. In many or most genera of hairy ant-plants, long, erect pubescence also occurs in non-myrmecophytic congeners. It therefore seems likely that docile, small-bodied ants initially sought safe nesting and foraging sites on hairy plants prior to the evolution of myrmecophytism in these lin- eages. A possible contemporary example of such a relationship is that between Wasmannia scrobifera and a non-myrmecophytic hairy Piper species in Costa Rica (D. Davidson, personal observation). These ants build small fragile carton nests on abaxial leaf surfaces, where they feed on pearl bodies. Nests are not limited to individual host plants, nor are the ants likely to be obligate plant-ants. In some cases, ant dependency on plant trichomes may be restricted to the early stages of colony foundation. Thus, certain Azteca species regularly initiate colo- nies on pubescent ant-plants like Cordia and Tococa but later prune runways through host-plant tri- chomes and form carton satellite nests on neighbor- ing trees lacking protective trichomes ("i" in col- 28 Journal of Hymenoptera Research Fig. 4. Tiny Pheidole minutula Mayr workers travel easily among the erect trichomes of this myrmecophytic Clidemia. Numerous ant species with tiny workers use such "trichome myrmecophytes" as protected feeding and nesting sites, where they are safe from larger-bodied competitors and predators. umn 4 of Appendix 1 ; D. Davidson, personal obser- vation, Benson 1985). Contemporary distributions of ants across myrmecophytes in Africa and the Neotropics illus- trate the influence of plant trichomes on the match between ants and plants (Appendix 1). First, in both regions, worker ants of pubescent myrmecophytes are short-bodied (<3 mm), with short turning radii, and do not include longer-bodied pseudomyr- mecines. Included here are two neotropical genera with functional stings {Allomerus and Solenopsis), and docile African dolichoderines in the genus Technomyrmex (species formerly placed in Engramma, Shattuck, 1992a). All known hosts of Allomerus and Solenopsis possess long erect pu- bescence. Allomerus is particularly conspicuous in its association with a diversity of pubescent host genera, seven in total. Of the recorded hosts of African Technomyrmex, species in five (and possi- bly six) of eight genera are hairy; only two, Leonardoxa and Ixora hippoporifera, definitely lack trichomes. To the extent that members of competitively dominant ant genera depend on pu- bescent ant-plants beyond the incipient colony stage, the particular species represented in these associa- tions are unusually timid for their genera (e.g., the Crematogaster cf. victima group on melastomes, the tiny Crematogaster sp. on Delpydora, and the Azteca species inhabiting hairy Triplaris poeppigiana Weddell). Second, the body sizes of plant-ants tend to be correlated with trichome spac- ing (Davidson et al. 1989). This suggests that ancestral ants may have nested preferentially not only on pubescent plants but specifically on those where mean distances between trichomes were no larger than required by their own body sizes. The parallels with nest selection by stem diameter in generalized stem-nesting ants are obvious (see above). Third, if ants compete for host plants (see Davidson et al. 1989), and if small, timid species persist only where protected by trichomes from larger dominants (> 3 mm, e.g., Crematogaster and Azteca), then the dominants should prevail on myrmecophytes lacking inhibitory trichomes. This hypothesis is supported not only across ant-plant Volume 2, Number 1, 1993 29 genera (Appendix 1), but within several genera which are interspecifically variable in pubescence. In neotropical Cordia, for example, glabrous C. alliodora (R. and P.) Oken is regularly occupied by aggressive Azteca, but smaller and more timid Allomerus ants inhabit densely hairy C. nodosa. As noted above, a small-bodied and timid Azteca spe- cies inhabits the hirsute stems of Triplaris poeppigiana, though the vast majority of myrmecophytic Triplaris species are glabrous and occupied by long and narrow-bodied pseudomyr- mecines. Third, dominant Crematogaster ants oc- cupy glabrous African Canthium, whereas hairy congeneric hosts are associated with timid Technomyrmex species (Bequaert 1922, pp. 474- 475). The same may perhaps be true in African Cuviera, which contains both glabrous and hirsute myrmecophytes. Both Technomyrmex and Crematogaster are recorded as associates of ant- plants in this genus, but the distribution of different ants in relation to plant pubescence cannot be discerned from existing literature. Finally, as noted above, some ants 3 mm in body length occasion- ally occupy trichome myrmecophytes but regularly prune trail systems, which facilitate their move- ments (Davidson et al. 1989). Association of Camponotus ants with spiny palms in the genus Korthalsia may also have had its origins in the tendency of ants to feed and nest where the plant's growing tips are protected from the ants' natural enemies. Among the \2 Korthalsia species which Dransfield (1984) lists for Sabah, Malaysia, seven have armed ocrea and five do not. Of the species with spiny ocrea, all but K. ferox Becc. also show regular associations with ants, whereas this is true for none of the species with unarmed ocrea. Both the long, sharp and compara- tively dense spines of species K. echinometra Becc, K. hispida Becc. and K. robusta Blume, and the scattered, short, triangular spines of K, cheb Becc, K. furtadoana J. Dransf. and K. rostrata Blume are more likely to protect the ants from vertebrate predators than from other ants. Dransfield ( 1 98 1 ) found greater herbivory by vertebrates (perhaps squirrels) on growing tips of K. rigida Blume (with unarmed ocrea and sparsely armed leaf sheaths) than on those of K. echinometra and K. rostrata. Although he attributed this result to protection that ants might afford to the latter species, an alternative hypothesis is that both the plants' growing tips and the ant nests benefit from the armature of ocrea and leaf sheaths. This would not rule out some addi- tional benefit to the plant from its ants. Unfortu- nately, phylogenetic relationships remain unde- fined for both plants and ants, and it is not yet possible to determine the extent to which the vari- ous relationships between ants and armed Korthalsia evolved independently. However, Dransfield' s (1981 ) observation that Calamus species of New Guinea and the Philippines show parallel evolution of armed ocrea and relationships with ants suggests that myrmecophytism could have evolved more than once within Korthalsia as well. Similarly, myrmecophytic rattans in the genera Calamus and Daemonorops exhibit parallel evolution of ant gal- leries formed by interlocking combs of spines, forming collars on the leaf sheaths (Dransfield and Manokaran 1978). Rates of Resource Supply from Plants The impact of rates of resource supply on the match between ants and plants is best compared within host genera, holding food type approxi- mately constant. Within western Amazonia, for example, the rate of food body production by Ce- cropia varies across both species and habitat types (Davidson et al. 1991, Davidson and Fisher 1991, Folgarait and Davidson 1992). Faced with compe- tition from fast-growing pioneer species of similar stature, more light-demanding species of large riv- erine disturbances defer costly defense in favor of rapid growth. Because comparatively shade-toler- ant species of small forest light gaps experience light competition from much larger neighbors, di- version of limiting carbon from defense to growth might confer little benefit, and even jeopardize the persistence required to take advantage of later canopy openings. Thus, the more shade-tolerant Cecropia species produce swollen stems, prostomas, and trichilia much earlier in development than do their light-demanding close relatives (Fig. 5), as well as producing a greater dry weight of Mullerian bodies per unit leaf area. Despite this greater investment (proportional to the plant's resource budget) in biotic defenses by small gap Cecropia, 30 Journal of Hymenoptera Research there are at least three reasons why the absolute rates of food provisioning to ants are greater in light-demanding pioneers than in closely related but more shade-tolerant gap species. First, and perhaps foremost, the smaller sizes of forest gap species at the time of colonization by ants are associated with fewer leaves (sources of food re- wards) and slower plant growth rates. Second, even with plant size or light environment held constant, small gap Cecropia have intrinsically slower growth and leaf production rates than do their more light- demanding counterparts. Finally, comparatively low light intensities in their typical habitats further limit the capacity of the forest gap plants to produce ant rewards. Ants appear to respond to these quantitative differences in food production rates of Cecropia (Davidson et al. 1991, Davidson and Fisher 1991). For example, in southeastern Peru, patterns of ant associations are more closely tied to habitats than to host identities. Although the closest taxonomic relationships appear to be between Cecropia in different habitats (C. C. Berg, personal communi- cation ),Azteca ovaticeps Forel inhabits only intrin- sically fast-growing pioneers of riverine and stream- side habitats. In contrast, specialized Camponotus, Pachycondyla and Crematogaster species, and Azteca australis Wheeler are the typical residents of relatively slow-growing and congeneric hosts of small light gaps. Although the latter ants frequently colonize riverine Cecropia, they seldom establish colonies there, and they may usually be outcompeted by rapidly developing colonies of A. ovaticeps. This pattern holds both within and across host species, and it suggests that ant species may coexist locally by virtue of their "included niches". Spe- cies with rapidly growing colonies may dominate higher quality hosts, but be unable to tolerate low rates of resource supply. On the other hand, ants with relatively slow-growing colonies tolerate both high and low quality resources, but are usually excluded by competitors from fast-growing hosts. A similar pattern of niche differentiation is ap- parent within plant-ant guilds of other myrmecophyte taxa (including epiphytes) of both the New and Old World (Davidson and Epstein 1989, Davidson et al. 1989 and 1991). For ex- ample, specialized Tetraponera are the typical resi- dents of Barteria fistulosa Masters growing in small forest treefall gaps, but Cre matogaster domi- nate in large clearings (D. McKey, personal obser- vation). In Barteria nigritana J. D. Hooker, mostly restricted to light-rich coastal shrub vegetation, Crematogaster is the only recorded associate. In Leonardoxa africana Aubrev., Petalomyrmex is the typical associate of adult trees, and of a large proportion of juveniles. However, juveniles grow- ing in deeply shaded sites are usually occupied by Cataulacus (McKey 1984). The effects of insola- tion on resource quality can also be apparent within host species, as in the observation that Polyrachis species specializing on broad-leaved bamboos build their pavilions only in sunny areas of bamboo clumps (Dorow and Maschwitz 1990). At present, factors underlying interspecific dif- ferences in the resource demands of ants are poorly studied. However, just as the evolutionary diversi- fication of plants has been influenced by tradeoffs in allocation and life history strategies (e.g., Grime 1974), similar tradeoffs are likely to have contrib- uted to a proliferation of divergent ecological tac- tics in plant-ants (and ants in general, Tschinkel 1991, A. N. Anderson 1991). Included among these life histories may be: 1) opportunistic (rud- eral) species with rapid colony growth rates, high worker turnover, high resource demands, small (or moderate) colony sizes with correspondingly weak colony defense, short colony lifespans, and early reproduction; 2) "tolerant" species with slow-grow- ing colonies, low worker turnover, low resource demands, high longevity, deferred reproduction, and effective defense of the nest site, and 3) com- petitive species with rapid colony expansion, low worker turnover, and large, long-lived, aggres- sively territorial and well-defended colonies. The evolution of such divergent ecological strategies is likely to have been influenced also by phylogenetic constraints, such as preexisting uses of exocrine glands (Blum and Hermann 1978, Buschinger and Maschwitz 1984), or the form of the proventricu- lus, which controls the capacity for and efficiency of liquid food storage and transport (Eisner 1957). Such phylogenetic constraints might help to ex- plain why the competitive rankings and strategies of ants are often well-defined (though not perfectly so) at the generic level. Volume 2, Number 1, 1993 31 Fig. 5. Tiny seedling of Cecropia "tessmannii" , whose myrmecophytie traits appear approximately with the fifth through seventh leaves past the cotyledon stage, and when plants are < 10 cm tall. Because of its extreme morphological similarity to C. membranacea, C. (prov.) "tessmannii" is still technically lumped with that species (C. C. Berg, personal communication). However, C. membranacea. a pioneer of large, riverine disturbances, grows more rapidly and ac- quires its myrmecophytie traits at substan- tially and significantly later leaf nodes (Davidson and Fisher 1991). Other Traits of Weakly Competitive Ants Appendix 1 reveals numerous exceptions whereby the generic affiliations of ants are imper- fect predictors of subordinate or dominant status, as reflected by pruning behavior and association with trichome myrmeeophy tes or uncontested host plants. Nevertheless, some of these exceptions are consis- tent with the general principles developed here. For example, despite their chemical defenses, ants in some subgenera of Camponotus (especially Colpbopsis and Pseudocolobopsis) can behave as subordinates, living secretive lives inside their hol- low stem nests. Yet Camponotus of this description occur on a diversity of hosts that lack protective trichomes and, with one exception, they do not prune or attack vegetation around their hosts. At least two factors may explain the capacity of these species to persist on their hosts. First, major work- ers use their large and often modified heads to seal stem entrances effectively and to protect nests from invaders. Where ants obtain the majority of their resources from Coccoidea inside stems or domatia (e. g., under ocrea of Korthalsia), foraging occurs in seclusion and entails little risk. (A similar explana- tion may apply to the timid Pheidole colonies from myrmecophytie pipers and melastomes, which sup- ply food bodies inside domatia.) On the other hand, the extrafloral nectar of Endospermum and the Mullerian bodies of Cecro- pia, are produced on external plant surfaces. Here, the exclusivity of ant resources is protected in part by the temporary nature or temporal pattern of their production. For example, in the northern coastal forests of Papua New Guinea, Endospermum labios Schodde produces almost all of its extrafloral nec- tar in a brief pulse at about 3:00 AM, likely coincid- ing with the diel maximum in relative humidity there (Fig. 6). In contrast to myrmecophytie E. labios, a myrmecophilic congener, Endospermum medullosum L.S. Smith produces a greater fraction 32 Journal of Hymenoptera Research of its nectar during other periods of the diel cycle (D. Davidson, unpublished). Although many Ce- cropia species release Mullerian bodies slowly all day long, they also flush large numbers of these bodies just after nightfall (Davidson and Fisher 1991 ). Moreover, ants with generalized diets are usually not attracted to the bodies (Rickson 1977, D. Davidson, personal observation). Camponotus associates of Endospermum and Cecropia both forage on leaf surfaces principally at night, and workers of Anoplolepis (not a plant-ant) can range freely over Endospermum during daylight hours (D. Davidson, personal observation). (See also A. N. Anderson's [1991] discussion of nocturnality in Australian Camponotus.) Cladomyrma of Neonauclea are nocturnal as well (D. Davidson, personal observation), though the object of worker foraging on Neonauclea has yet to be identified. Finally, some plant-ants in the genera Myrmelachista and Allomerus are apparently restricted to their hosts diurnally, but make nocturnal forays to the forest floor (J. Longino, personal communication). Together, these observations suggest that competi- tion may be reduced somewhat at night, though the nature of any restrictions on nocturnal activity in dominants is not readily apparent. While activity schedules of temperate and arid zone ants are strongly related to diel variation in temperature and humidity regimes, biotic selection pressures could be equally important or more important determi- nants of foraging times in ants of moist tropical forests. ANCESTRAL VERSUS MODERN RELATIONSHIPS We have argued that the matching of ants and myrmecophytic plants is convergently alike in dif- ferent tropical regions, and that this convergence arises from the presence of similarly preadapted plants and ants within the respective biotas. In concentrating on the associations as they exist today, we have neglected the pathways by which they may have reached their present form. Ant- plant symbioses have undoubtedly evolved from more casual and opportunistic relationships be- tween plants and ants. In their initial phases, many of these associations would likely have resembled modern-day relationships in which plants lack ob- vious specializations for housing ants ( Appendix 1 , "N" in column 6). Like most other forms of mutualism (reviewed in Thompson 1982), many symbiotic ant-plant mutualisms probably began as parasitisms. What factors may have facilitated the transition from parasitism to mutualism, and what character transformations could have accompanied this change? For plants hosting ants inside primary domatia (live stems and internodes), ancestral relationships probably consisted of ants tending scale insects within natural plant cavities or in insect borings (cf., Ward 1991). From the start, ants must have benefitted from access to exclusive resources in these protected environments. However, to have remained entirely in the sanctity of the host plant, ants would have needed a well-balanced diet. Ho- mopteran exudates contain not only carbohydrates, but some amino acids and lipids (reviewed in Buckley 1987), and ant colonies are known to harvest and eat Homoptera to meet their protein requirements (e.g.. Way 1954, Pontin 1978). Fur- thermore, in both New and Old World tropics, as well as in Australasia, some plant-ants have evolved means of obtaining added protein and fats from elaborated calluses or heteroplasias caused by trau- matic injury to either the inside (Tetraponera on African Vitex, Bequaert 1922) or outside of host plant stems (South American Pseudomyrmex on Triplaris, and New Guinea Camponotus on Endospermum [D. Davidson, personal observa- tion ] , and possibly Central American Myrmelachista on Ocotea [J. Longino, personal communication]). In large part then, coccoid-tending residents of live stems and cavities could probably have depended on hosts to satisfy most or all of their nutritional needs, even from the earliest stages of their rela- tionships with these plants. In contrast, the impact of symbiotic ants on their host plants would have depended on the balance struck between resource losses to scale insects and ants, and any anti-herbivore protection the ants may have originally afforded. Although the majority of ants would probably have provided at least some protection against stem and leaf parasites, the Coccoidea would surely have been a liability. Substantial carbohydrate losses sustained by the Volume 2, Number 1, 1993 33 Fig. 6. This large drop of extrafloral nectar was produced in a brief pulse at 3:00 AM on the petiolar nectaries of Endospermwn labios, at the Christensen Research Station near Madang in Papua New Guinea. (Screenhouse plant courtesy of M. Jebb.) plants should have been most debilitating to car- bon-limited (light-limited ) plants. Thus, in habitats of low light intensity, natural selection on plants may have acted mainly to exclude both ants and Homoptera. However, where light was abundant, the benefits of ant defense could have outweighed carbohydrate losses (on average). Natural selection on these plants should have favored attraction of ants, rather than resistance to them. In this way, the propensity of ant-parasitized plants to evolve to- ward myrmecophytism could have been facilitated by high availability of carbon (light) in relation to limiting mineral nutrients, and impeded when such ratios were low. Furthermore, if herbivore pres- sures are generally more intense in comparatively productive, sunny environments ( see Davidson and Fisher [1991] for Cecropia), this trend could have reinforced selection for ant attraction in such habi- tats. Although our data set lacks the resolution to test this hypothesis, the hypothesis is consistent with the central result of Schupp and Feener's (1991) recent survey of the distribution of ant attractants (EFN's and pearl bodies) within the flora of Barro Colorado Island, Panama. While the occurrence of such rewards was clearly correlated with phylog- eny, it also appeared to depend on the light environ- ment. Plant families characteristic of forest light gaps were overrepresented among ant-defended families. (See also the frequency of superscripts "e" and "g" in column 2 of Appendix 1.) Schupp and Feener hypothesized that the high frequency of ant defenses among forest gap plants may be ex- plained by the comparatively low costs of produc- ing carbohydrate ant rewards in these light-rich habitats, as well as by the tendency for relatively continuous growth and leaf production in gap spe- cies. The latter explanation meshes well with McKey's (1989) interpretation of biotic defenses as an alternative to phenological escape from her- bivory (i.e., escape from detection, due to variable and unpredictable new leaf production). Pheno- logical escape would be unavailable to plants with continous leaf production. There are some indications that the absence of scale insects may be the derived condition in rela- tionships involving pseudomyrmecines (P. Ward, personal communication). Thus, although Coccoidea can be found at the bases of spines on African and Indian Acacia housing Tetraponera, 34 Journal of Hymenoptera Research Pseudomyrmex-ivhabited Central American Aca- cia lack scale insects but supply protein-rich Beltian bodies. Moreover, the gnawing of internal stem walls by Tetraponera tessmannii (Stitz) on African Vitex, to produce tunnels with terminal nutritional heteroplasias, could have had its origins in the excavation of pits to increase the feeding efficien- cies of coccoids, now absent from this system (see Bailey 1922 for Cuviera). For plants that continued to be inhabited by ants and scale insects, natural selection would be ex- pected to favor a reduction in the ratio of coccoid to ant biomass. Although many obviously specialized ant-plants still harbor Coccoidea (Appendix 1 ), there is considerable variation across all the ant- plants in the densities of scale insect populations (D. Davidson, personal observation). At one ex- treme are the comparatively unspecialized relation- ships between Anonychomyrma (previously Iridomyrmex [Shattuck, 1 992b] ) and Crematogaster ants, and a number of pachycaulous understory New Guinea trees. Here, the biomass and density of Cryptostigma scales are so great that their popu- lations may well be limited by either plant re- sources or the availability of feeding sites (D. Davidson, personal observation). In contrast, in its more specialized relationship with Triplaris americana L., Pseudomyrmex dendroicus Forel maintains only approximately one scale insect per leaf junction, and similarly low coccoid densities are apparent in Cecropia stems inhabited by Azteca ovaticeps and A. australis. By what proximate mechanisms might plants have responded to selection for reducing losses to Homoptera? For myrmecophilic plants, Becerra and Venable (1989) have argued that EFN produc- tion could have arisen as a means of paying ants directly and eliminating parasitic homopteran in- termediates. Even if EFN*s provided ant rewards comparable to or lower in value than homopteran secretions, reduced resource handling times might have induced ants to feed at nectaries and to aban- don their Homoptera. In turn, plants would have benefitted from lower rates of infection with ho- mopteran-mediated diseases and possibly lower resource losses. One difficulty with applying this theory to the evolution of myrmecophytes is that it ignores an important distinction between coccoids (the usual homopteran associates of plant-ants) and EFN's. While EFN's are relatively promiscouous resources, accessible to many ants, coccoids tended inside cavities can be used exclusively by symbi- otic ant associates. If the latter ants are the most effective mutualists of the plant, and provide better protection in the absence of opportunistically for- aging competitors, selection may favor loss of EFN's. There is evidence for such a scenario in myrmecophytic Asian Macaranga, which, in con- trast to their non-myrmecophytic congeners, al- most completely lack EFN's (Fiala and Maschwitz 1991). A second difficulty with the hypothesis of Becerra and Venable (1989) is that it ignores the possibility that colonies might keep pace with the added resources (EFN) through short-term rede- ployment of workers or long-term growth. If so, ants might continue to tend Homoptera while also feeding from EFN's. A plausible alternative hy- pothesis is linked to the assumption that growth of ant colonies (like that of plants. Bloom et al. 1985) is limited by the ratio of carbon and nitrogen re- sources. By rewarding ants with abundant carbo- hydrate but starving them for protein (Carroll and Janzen 1973), plants might have induced colonies to consume the majority of their Homoptera. In support of this argument, Oecophylla longinoda is known to consume more coccoids when given a supplemental sugar source (Way 1954). Moreover, M. Anderson (1991) attributes "switching" be- tween predation and mutualism in ant-homopteran relationships (see also Pontin 1958 and 1978) to changes in the nutritional status of the ant colony. If homopteran populations are regulated in re- sponse to ratios of carbon and nitrogen availablity to ants, colonies might be expected to maintain their associates at densities which supply these resources at optimal ratios for colony growth. Cur- rently, a lack of data prevents further speculation as to how the relative availability (to ants) of carbohy- drate and protein might vary with homopteran densities. Future investigations might profitably focus on natural or experimentally induced varia- tion in the relative biomasses of ants and Homoptera in particular ant-plant systems. Volume 2, Number 1 , 1 993 35 PLANT FITNESS IN RELATION TO ANT SPECIES In many ecological studies of ant-plant symbio- ses, investigators have focused principally on the question of whether or not a given ant associate benefits its host species. With recently renewed appreciation for the diversity of ants colonizing individual myrmecophytes comes the realization that ants may differ in the protection afforded their hosts (e.g., Janzen 1975,Ohveiraetal. 1987, Rico- Gray and Thien 1989. Davidson etal. 1991,Longino 1991a and b, but see Vasconcelos 1990, for a counterexample), and that associations must be studied in the context of community-wide interac- tions. While existing data are too meager to corre- late protection with specific ant traits, some conjec- tures are warranted. Rapid colony development, large colony size, and high levels of worker activity should enhance host-plant defense. Large insect herbivores (Coleoptera and Orthoptera) may be best deterred by active, large bodied workers (Davidson and Epstein 1989). In contrast, division of colony biomass among numerous small foragers may promote fine-grained searching and facilitate the detection of small prey, for example, lepi- dopteran eggs (Letourneau 1983. Vasconcelos 1 99 1 ). Some authors have suggested that small and timid ants provide little protection against herbi- vores, but augment the nutrient reserves of their hosts through deposits of feces and refuse (e.g., Janzen 1974b,Beattie 1985). However, at least two studies have confirmed the effectiveness of small, docile Pheidole ants in defending against either insect eggs (Letourneau 1983), or herbivorous lepi- dopteran larvae (Vasconcelos 1991). While nutri- ent enhancement has been demonstrated convinc- ingly in myrmecophytic epiphytes and palms (Rickson 1979. Rickson and Rickson 1986), tests have disputed the theory for the symbiotic associ- ates of Macaranga (Fiala et al. 1989) and Muieta (H. Vasconcelos and B. Forsberg, personal com- munication). On reflection, possibilities for nutri- ent enhancement are limited by the infrequency of foraging off the host (Appendix 1, column 4) and, consequently, by the inability of ants to concentrate materials from the broader environment. Two other cases are likely candidates for nutri- ent augmentation by ants (D. Davidson, personal observation). First, certain Azteca species center their carton nests on Tococa and Hirtella species and contribute to a steady rain of carton and refuse at the base of the host tree trunk. Second, as a rheophy te of stream beds and rocky river beaches, Myrmeconauclea strigosa (Korth.) Merrill grows with its roots anchored in rock crevices. The Crematogaster ants, which are its dominant associ- ates in forests west of Lahad Datu, Sabah. pack refuse and feces into domatia at the distal branch tips, from which new swollen internodes arise. The absence of any obvious food reward (including Homoptera) suggests that ants might leave their hosts to forage. If such is the case, workers could concentrate nutrients which enhance fitnesses of hosts growing in extremely nutrient-poor environ- ments. In some cases, myrmecophytism actually con- tributes to host-plant damage by destructive verte- brate predators of ant larvae (especially by wood- peckers [Carroll 1983] and monkeys [Freese 1976, and J. Terborgh, personal communication, for Ce- cropia). Damage by primates may be less common for hosts of ants with powerful stings. First, in Peruvian Amazonia, Pachycondyla luteola Roger (the "pungara") is an obligate symbiont of Cecro- pia, and its painful barbed stings reinforce verte- brate learning for a period of seven to ten weeks (D. Davidson, personal observation). Avian prefer- ences for nesting in this (Koepcke 1972) and other myrmecophytes with stinging ants (Young et al., 1990) may be at least partly attributable to the protection which ants afford against primates. Sec- ond, the Tetraponera of African Barteriafistulosa also impressed Janzen (1972) as effective deter- rents of vertebrates, and a black colobus monkey avoided ant-occupied Barteria, while feeding on an unoccupied individual nearby (McKey 1974). Gray- cheeked mangabey monkeys (Cercocebus albigena [Gray] ) rip open the branches of this host to prey on Tetraponera brood, but only if this can be accom- plished by reaching from a perch in a different tree (D. McKey. personal observation). Even large, stinging plant-ants may not affect some vertebrates, however. Gorillas in the Central African Republic feed on B.fistulosa leaves and branches apparently undeterred by healthy, active colonies of 36 Journal of Hymenoptera Research Tetraponera (M. Fay, personal communication). Finally, because plant-ants with functional stings also usually prune the vegetation surrounding their hosts, crowns inhabited by such ants are usually sufficiently isolated in forest gaps to avoid the attacks of primates which visit neighboring trees. TRENDS IN SPECIALIZATION, SPECIFICITY AND COEVOLUTION Because the evolutionary histories of symbiotic ant-plant systems have been largely independent in biogeographically disjunct tropical regions (McKey and Davidson, in press), intercontinental compari- sons may provide general insights into the evolu- tionary dynamics of such systems. In this section, we discuss evolutionary interactions between ants and plants, focusing on three questions: (1) Has specialization of ants and plants followed similar evolutionary pathways due to parallel and/or con- vergent evolution in organisms from different con- tinents? (2) Have evolutionary interactions be- tween ants and plants contributed to the generation of diversity in plant-ants and ant-plants? ( 3 ) If so, are these interactions a partial cause of interconti- nental differences in diversity of ant-plants and plant-ants? Again we focus mainly on the Ameri- can and African tropics, whose ant-plant associa- tions are best known. The Nature and Causes of Specificity Symbiotic ant-plant systems are in general more species-specific than are nonsymbiotic ant-plant interactions (e.g., Schemske 1983). All tropical regions contain examples of ant-plants that are obligately associated with one or a small number of plant-ant species, which in turn have comparably restricted host-plant ranges. In such cases, speci- ficity is doubtless a product of intense evolutionary interaction. However, much of the seeming speci- ficity in ant-plant symbioses may be maintained by ecological processes that require no evolutionary specialization in ant or plant. We have argued that characteristic and repeatedly observed plant-ant matches are the result of species sorting (Jordano 1 987 ) of plants and ants which are mutually pre- adapted in many attributes related to the interaction (Davidson et al. 1989 and 1991, Davidson and Fisher 1991). Driven by the strong competitive interactions that structure communities of arboricolous ants, the matching of plants and ants is determined by plant and ant traits which modify ant access to plant resources. In a growing number of ant-plant systems, we now recognize that seemingly specialized plant- ants may be capable of living on any of several hosts, and that many or most myrmecophytes can persist in association with any of several plant-ants. Nevertheless, some relationships are more frequent and/or more durable than others. Understanding the ecological processes which reduce broad poten- tial niches of plant-ants and ant-plants to narrower realized niches is a prerequisite to an evolutionary investigation of such systems (Davidson and Fisher 1991). First, ecological studies suggest simpler alternatives which must be excluded before hy- potheses of evolutionary specialization andcoevo- lution can be entertained. Second, if ecological causes of specificity can be defined, these will suggest the likely selective environments in which any evolutionary specialization may have taken place. Third, studies of unusual associations may give clues about the origin of both host-plant speci- ficity and host switches, which seem to have taken place frequently in symbiotic ant-plant systems (Ward 1991). Evolutionary Specialization of Ants and Plants If competitive interactions among ants are suffi- ciently strong and constant, ecological sorting will produce predictable patterns of ant-plant associa- tions and a selective environment conducive to evolutionary specialization (Schemske 1983). Evi- dence from various tropical regions suggests that evolutionary specialization of ant-plants and plant- ants may have been driven largely by competition among ant species. Even strong pairwise ant-plant mutualisms, it appears, owe many of their traits to an evolutionary background of multispecies an- tagonistic interactions. Whether these character states were evolved in the context of the symbioses, or merely fine-tuned from pre-existing traits, often cannot be argued confidently from existing data. Nevertheless, many traits of both plant-ants and their hosts may have been elaborated because of Volume 2, Number 1, 1993 37 their selective value in the context of symbiotic association. Ants. — Because ants actively choose their hosts, selection should strongly favor specializations for rapid and efficient host location by queens. In addition to minimizing exposure to predation and other environmental hazards, such adaptations could help to assure priority of access to contested re- sources. Indeed, competitively inferior ants might even usurp the hosts of more dominant species by evolving rapid means of finding and entering these plants. First, almost nothing is known about the kinds of information that queens employ to locate suitable hosts, but a variety of chemical, visual and other cues may be used at different stages of host identification. Whatever the mechanisms of host identification, the abilities of queens to locate and colonize specific hosts, and their absence from other hosts and habitats (Davidson et al. 1 989. Fiala and Maschwitz 1990, Morawetz et al. 1992), pro- vide some of the strongest evidence of evolutionary specialization to the symbiosis. Second, the ex- treme dorsiventral flattening of the head, thorax and abdomen of Petalomyrmex queens could have arisen due to selection for rapid entry of myrmecophytes in the face of intraspecific and interspecific competition for hosts (McKey 1991 ). Alternatively, however, specialized queen shapes might have evolved first in generalized stem-nest- ing ants (Longino 1989b), preadapting such ants to become specialized plant-ants. Without additional phylogenetic analysis, adaptations in body shapes remain indistinguishable from preadaptations. Once foundresses have safely entered a host, their success on plants of different growth rate, maximum size, or lifespan, will likely depend on key energetic, demographic, and life history fea- tures of the colony. Intrinsically rapid rates of egg production and development of incipient colonies could be favored on fast-growing plants, and pleometrosis might substitute for this in at least some ant species ( Davidson et al. 1 99 1 ). However, before evolutionary specialization can be inferred from an apparent matching of colony attributes and plant growth rates, careful phylogenetic analysis must exclude the alternative hypothesis that ant traits evolved prior to the origin of the symbiosis. In the case of IheAzteca and Cecropia, this caution is reinforced by the likelihood that A. ovaticeps and its relative A. alfari, may have originated from a weedy species which was typical of second growth vegeta- tion (Longino 1991b), and whose life histories could have preadapted it for occupation of rela- tively fast-growing hosts of riverine succession. In contrast,/!, australis and its relative A. xanthochroa Roger, are probably derived from carton-building ancestors (Longino 1991b), whose comparatively permanent homes may have predisposed them to evolve life history traits typical of modern-day descendants on slower-growing and, in most cases, longer-lived, forest gap Cecropia. Many or most specialized plant-ants appear to have been relatively weak competitors, in which aggressive behavior could well have been maladap- tive. Nevertheless, within the limited spheres of their host plants, a number of these ants appear to have evolved greater similarity to dominants, de- fending absolute territories defined by the bound- aries of individual trees. Thus, one scenario appar- ent in several plant-ant lineages is that of increased colony size and aggression in response to symbiotic association with myrmecophytes (e.g., Janzen 1966). For example, the extended colonies of Myrmelachista ants on pure stands of Tococa occidentalis (see above ) reach an estimated worker population 1-2 million ants (Morawetz etal. 1992). Moreover, on Peruvian Cecropia, Pachycondyla luteola exhibits the largest and most aggressive colonies achieved by any ponerine ant. Host trees >30 m tall literally seeth with aggressive, stinging workers, and populations almost certainly range into tens or hundreds of thousands of workers (D. Davidson, personal observation). Even if rigorous phylogenetic analysis confirms that closest rela- tives of these ants have much smaller and less aggressive colonies (as do Pachycondyla sp. nov. on Panamanian Cecropia hispidissima Cuatracasas, Davidson and Fisher 1991), ecological studies will be necessary to determine whether the purportedly evolved demographic responses of P. luteola are examples of evolutionary accommodation or only plasticity in colony structure. For colonies nesting and feeding in the comparative security of myrmecophytes, increasing worker life spans, and nest sites which grow, rather than decaying (like dead twigs), could lead automatically to larger 38 Journal of Hymenoptera Research worker populations, and greater aggression might follow as a behavioral response to colony size. Similarly, the polygyny and/or pleometrosis noted as typical or occasional in some purportedly highly specialized plant-ants (Janzen 1966 and 1973, McKey 1 984, Davidson and Epstein 1 989, Longino 1989b, Vasconcelos in press) may be a plastic response to resource availability or competition, since queen number can vary similarly in other ant species (Ward 1989b, Holldobler and Wilson 1990). Although queens of Azteca australis found their colonies individually on isolated hosts in small light gaps, they often cooperate to initiate colonies on the faster growing plants of riverine distur- bances, where both rates of food supply and com- petition from other incipient colonies are greater (Davidson et al. 1991). At present it is unclear whether pleometrosis in the latter environment arises from evolutionary adaptation to competition or merely from greater numbers of alates produced and available in that habitat. Pruning of vines and other vegetation in the vicinities of hosts is one trait which provides less ambiguous evidence for evolutionary accommoda- tion to competition for hosts. Facultative pruning, requiring the presence of enemy ants, may eventu- ally prove to be widespread among unspecialized close relatives of obligate plant-ants. However, both obligate pruning, and the maintenance of vegetation-free zones at the host-plant base, appear to occur predominantly in ants whose highly spe- cialized diets (Janzen 1966, Davidson et al. 1989, Fiala and Maschwitz 1990, Morawetz et al. 1992) and unitary host genera (but see Ward 1991 ) pro- vide independent evidence for specialization. A final category of specialized ant traits may have little or no relevance to competitive ability but nonetheless serve as useful indicators of degree of evolutionary specialization in plant-ants. For ex- ample. Ward's (1991) phylogenetic analysis of pseudomyrmecines points to trends for plant-ants to have reduced eye size and palpal segmentation, as well as hypertrophied metapleural glands (ex- cept in cacia-ants). Palpal segmentation is also reduced in African Engramma (now included in Teclmomyrmex, Shattuck, 1992a), in comparison to other dolichoderines from the Ethiopian region (Holldobler and Wilson 1990). Reduction in anten- nal segmentation occurs in some lineages of Allomerus (Wheeler 1942), and arboreal stem-nest- ing Cladomyrma have fewer antennal segments than do most other formicines (Holldobler and Wilson 1990). Although 10-merous antennae are characteristic of more generalized Myrmelachista species (subgenus Hincksidris) which nest in dead stems, specialized Central American Myrmelachista plant-ants have antennae with only 9 segments. Lastly, barbed stings are probably derived in both Pseudomyrmex ants (Janzen 1966) and Pachycondyla luteola (D. Davidson, personal ob- servation). In general, sting defenses may be more effective against solitary vertebrates than against social insect enemies (Davidson et al. 1988), and barbed stings may have evolved under selection to reinforce learning by vertebrate enemies. Plants. — In myrmecophytes, domatia and vari- ous food rewards offer clear support for evolution- ary specialization, all the more so since the produc- tion of such structures can entail obvious costs. Ecological costs of myrmecophytic traits may be evident in both the presence of ants, as when ant predators open the nests (see above), and in their absence, e.g., when herbivores invade and inhabit foliar or stem domatia (Jolivet 1991, Vasconcelos 1991). Costs are most evident, however, when myrmecophytic traits are lost in the absence of symbiotic ants. For example, though Cecropia peltata L. is myrmecophytic throughout most of its distribution, conspecifics in Caribbean island popu- lations lack Miillerian bodies and have trichilia reduced or absent (Janzen 1973; Rickson 1977). (Non-myrmecophytic Cecropia schreberiana Miquel might have been mistaken for C. peltata on some of these islands [C. Berg, personal communi- cation].) In more recent history, introduced Cecro- pia obtusi folia Bertoloni of Hawaii, and C. peltata imported to both Asia and Africa have either lost their Miillerian bodies or trichilia, or are polymor- phic for these characters and exhibit a range of trichilia sizes (D. Davidson, personal observation, Putz and Holbrook 1988). Although it could be argued that such losses are determined environ- mentally, rather than genetically, African popula- tions oi Cecropia peltata lacked trichilia even when grown from seed in greenhouses, where progeny of myrmecophytic congeners from their native habi- Volume 2, Number 1, 1993 39 tats have never failed to produce trichilia ( Davidson, unpublished). Selection may also act on plant characteristics which influence the outcome of ant-ant competi- tion for the resources offered. In so doing, evolu- tion might enhance traits which favor the most effective mutualists (at levels of defense invest- ment optimal for the plant) over their competitors. Perhaps most remarkable. Piper ant-plants appar- ently produce food bodies only when stimulated to do so by the appropriate Pheidole ants (Risch and Rickson 1981 ), or by specialized parasites of the ant-plant mutualism (Letourneau 1990 and 1991). The persistence of Mullerian bodies on Cecropia trees lacking specialized ants (Rickson 1977, D. Davidson, personal observation ) provides evidence that these bodies are not recognized by unspecialized ants as suitable food. Moreover, Mullerian bodies of at least Cecropia (prov.) "tessmanii", Cecropia hispidissima, and possibly Cecropia ficifolia Snethlage appear to have been modified evolution- arily to favor their usual resident ants (Davidson and Fisher 1991). In a variety of ways, selection might modify the quality, rate, timing or position of the food reward to encourage either fine-grained or coarse-grained foragers, large or small workers, and aggressive, energy-intensive competitive dominants or timid, energy-conservative subordinates (see above). As an extreme example, plants which provision ants with complete diets may facilitate the persistence of weakly competitive species, whose foraging can then be restricted to the host itself (Appendix 1, column 4). At least some species of Triplaris induce fine-grained foraging by ants with highly specialized foraging behaviors. These hosts pro- duce pearl bodies which are unique in their yellow color (perhaps indicative of some distinctive nutri- tional quality) and are distributed in patches on adaxial leaf surfaces. Perhaps pre-adapted for this behavior by prior dietary specialization on pollen and fungal spores (Wheeler and Bailey 1920), the Pseudomyrmex residents of these myrmecophytes accumulate these tiny food bodies on their append- ages while constantly traversing leaf surfaces. They groom the material frequently onto their sting sheaths, which serve as storage sites until workers return to their nests (Davidson et al. 1988). In a number of ant-plant genera, food rewards for ants are often produced in more localized and defensible sites on true myrmecophytes than on myrmecophilic relatives with more promiscuous rewards. Thus, in the Endospermum of New Guinea (Airy-Shaw 1980), myrmecophilic E. medullosum has moderately sized EFN* s scattered across abaxial leaves along primary and secondary veins. Petiolar nectaries are only slightly larger. In comparison, myrmecophytic congeners have greatly enlarged petiolar EFN's and all other EFN' s greatly reduced in size and number. Similarly, in the genus Macaranga, at least some myrmecophilic species have scattered pearl bodies used by a number of unspecialized ants ( D. Davidson, personal observa- tion in New Guinea), whereas the most highly evolved myrmecophytes restrict access to food bodies by hiding them beneath recurved stipules. In incipient myrmecophytes, M. hosei King ex Hk. f. and M. pruinosa ( Miq. ) Muell. Arg., whose stems are not naturally hollow and are only partially occupied, accessibility of food bodies appears to be intermediate (Fiala et al. 1991). Thus, although food bodies are locally concentrated on stipules, the stipules are horizontal, leaving them exposed. Experimental studies might focus profitably on the outcome of ant-ant competition in relation to the spatial patterning, accessibility and defensibility of ant rewards. Similar relationships are well ac- cepted for other plant-animal mutualisms (e.g., Feinsinger and Colwell 1978). Restrictive entrances to domatia (Fig. 7) may render these structures more readily habitable by some ants than others, as well as limiting access to stem-dwelling Coccoidea. Prostomas of myrme- cophytic Leonardoxa are matched to the shapes and sizes of their associated ants (McKey 1991). Urticating hairs on the prostoma of Cec ropia (prov.) "tessmannii" favor large-bodied queens of Pachycondyla luteola over smaller-bodied Azteca queens (Davidson and Fisher 1991). In general, neither the selective effects of these traits on differ- ent ant associates, nor their consequences for plant fitness are well documented. Nor is it often clear where "preadaptation" stops and adaptation be- gins. For example, the thin pith cavities of myrmecophytic Vitex lianes are easily exploited by the plant's specialist associate, the slender 40 Journal of Hymenoptera Research Tetraponera tessmannii, but not by stouter ants of similar body length. At present, however, there is no evidence to suppose that either plant or ant has evolved to produce or enhance such a match. Even the long, elliptical prostoma ofLeonardoxa africana, matched to the flattened queens of Petalomyrmex (McKey 1991), might be explained as preadapta- tion. As in numerous other ant-plants with stem- domatia, this myrmecophyte's prostoma occurs at the node, opposite the leaf insertion, where a reduc- tion in xylem leaves the stem wall relatively thin (Bailey 1922). In future studies, both field experi- ments and careful phylogenetic analyses of plant and ant lineages will be required to determine how frequently myrmecophytes may have evolved to influence ant-ant competition. Limits to Specialization The forces leading to specialization in ant-plant symbioses are both clear and consistent with theo- retical arguments predicting greater specialization in mutualistic systems where strong antagonistic interactions occur among competing mutualists (Law and Koptur 1986). What factors then limit species specificity and account for the persistence of systems in which multiple ants coexist on the same host, or a single ant occupies several hosts? What are the limits to specialization? First, the matches produced by ecological sorting do not necessarily result in mutualistic interactions. A plant may be fortuitously "preadapted' to harbor a persistent parasite, as well as an effective mutualist. Depending on the match, an association might engender strong reciprocal specialization (when most effective mutualists are paired), asymmetrical specialization, or even antagonistic interactions in which specialization in ants and plants proceeds in opposite directions. Even when ant-plant associations are funda- mentally mutualistic, there may be both genetic and ecological limits to specialization and coevolution (Schemske 1983, Kiester et al. 1984, Howe and Westley 1988). The nature of any genetic con- straints is purely a matter for speculation. By and large, we do not know the extent of heritable variation for relevant ant and plant traits, nor whether such variation might limit specialization. Like- wise, population structure of ant-plants, and espe- cially that of plant-ants, is too poorly understood to support much discussion of how specialization and species origination might take place in these sys- tems. Since sexual selection can drive rapid evolu- tionary specialization and coevolution in mutual- ists, added information on ant mating sites and behaviors or data from genetic markers might be especially interesting in helping to determine whether mating could be non-random with respect to the host species where alates originated. More can be said about potential ecological limits on the intensity of selection for specializa- tion. Most significantly, the outcome of an ant- plant interaction may often depend not only on the specific identities of associates but also on habitat type and plant size. As summarized above, habitat may influence the match between plants and ants through both ecological and evolutionary variation in rates of resource supply to ants. The effects of habitat heterogeneity could also be mediated through other mechanisms that are still poorly understood. For example, on isolated plants, or where nutrient poverty limits productivity and alate production, low frequencies of host plant colonization may reduce the intensity of ant-ant competition for hosts (Vasconcelos, in press, D. Davidson, personal ob- servation). Herbivore pressures on at least some myrmecophytes appear to differ with habitat and plant size (Davidson and Fisher 1991, Janzen 1974a, Letourneau 1983), as does the probability that overgrowing vines will threaten both the host and resident ant colony (Rickson 1977, Davidson and Fisher 1 99 1 ). Perhaps also varying with habitat are the densities of queen and brood parasitoids, which either kill incipient colonies, or prolong their devel- opment (Davidson and Fisher 1991). Finally, the outcome of competition among ants for host plants may be influenced by habitat-correlated physi- ological effects on colony development. In Azteca ovaticeps, queen mortality prior to first worker production is much higher on shaded hosts at the forest edge than on hosts of large, sunny and hot riverine disturbances (Davidson et al. 1991). In both the Azteca of South American Cecropia and myrmelachistines of African Leonardoxa, inter- specific variation in queen color correlates with habitat in a manner consistent with the hypothesis Volume 2, Number 1, 1993 41 Fig. 7. Restrictive entrance to domatia of the African myrmecophyte Leonardoxa africana (Baill.) Aubrev. (Fabaceae: Caesalpinioideae). The plant's mutualistic ant associate, Petalomyrmex phylax Snelling, makes these slit-like entrances at the site of the prostoma, which is of similar shape. The entrance allows access by the specialized dorsoventrally flattened foundresses of P. phylax. but not by other ants of similar size. Workers of P. phylax are of normal shape, but can easily pass through these entrances because they are much smaller than dealate queens of Petalomyrmex or workers of other ant species associated with the plant. that black queen coloration could be adaptive on fast-growing hosts, possibly because of a positive effect on physiological rates. Queens are black in A. alfari, which dominates Cecropia of roadsides and pastures in many disturbed regions, and yel- lowish brown in A. ovaticeps, the typical resident of fast-growing riverine Cecropia (Longino 1989b). Occurring mainly on Cecropia of small forest light gaps, A. australis has yellow queens, and may have comparatively slow rates of egg-laying (Davidson et al. 1991 ). Similarly in Leonardoxa, black-bod- ied queens (and workers) of Aphomomyrmex tend to occur in more exposed riverine situations, whereas reddish yellow Petalomyrmex are typical of more shaded forest understory. Within myrmecophyte species, host size-de- pendent variation in the relative abundances of alternative plant-ants may be determined in some cases by the match between colony resource de- mands and rates of resource provisioning by the plants. However, other causal mechanisms might also produce correlations between plant sizes and the identities of ant inhabitants. For example, such correlations could occur if ant species differed in the capacity to protect their hosts from herbivory (suggested by Longino 1991a and b, for Central American Azteca on Cecropia). Additionally, a form of ecological succession may take place, with regular changes in ant inhabitants through indi- vidual plant lifespans. Turnover of ant species 42 Journal of Hymenoptera Research through time has been observed on hosts in the genera/lcflc7<7 ( Janzen 1 975 ), Leonardoxa (McKey 1984), Tachigali (Benson 1985), and Maieta (Vasconcelos 1990). Just as successional mecha- nisms may vary across plant communities (Connell and Slatyer 1977). they may also vary across ant- plant systems. One possible explanation for spe- cies replacements is that early colonists are eventu- ally replaced by superior competitors (Janzen 1 975, McKey 1984, Davidson et al. 1989). In this context, coexistence of multiple ant species on a single host population requires that competitive abilities be inversely proportional to colonizing abilities, with poor competitors making a living as "fugitive species". Even in the absence of direct interspecific inter- actions, disparate ant life histories might lead to successional changes among the ants of individual hosts. On Central American Acacia, for example, Pseudomyrmex nigropilosa Emery is an opportu- nistic colonist and short-term resident after prior residents have died from fire and other causes (Janzen 1975). A similar mechanism has been proposed by Vasconcelos ( 1 990) to account for the coexistence of Pheidole minutula Mayr and Crematogaster sp. on Maieta guianensis Aublet near Manaus, Brazil. Although the two ant species provide equivalent protection for their hosts, the frequency of Pheidole occupancy increases with plant size. Comparatively early death or desertion of hosts by Crematogaster (for unknown reasons) leaves plants to be colonized again. Whatever the average relationship between the colonizing abili- ties of the two ants, larger plants should eventually accumulate Pheidole colonies, due to the frequent abandonment of hosts by Crematogaster. To summarize, both the species composition of ant-plant symbioses, and the fitness consequences of particular associations, can vary markedly in space and time. Just as such inconsistencies are postulated to have limited evolutionary specializa- tion in non-symbiotic ant-plant relationships (Schemske 1983, Beattie 1985), they have likely been the predominant obstacles to the evolution of species-specificity in symbiotic associations. Evolutionary Dynamics of Ant-plant Symbiosis Given these limitations to species specificity, what are the implications for coevolution? Coevo- lution has two aspects. The first is co-accommoda- tion, reciprocal evolutionary responses of interact- ing organisms (Mitter and Brooks 1983). Co- accommodation is most easily recognized when it involves functionally matched characters of associ- ated organisms or coupled character coevolution (Schemske 1983). Several ant-plant systems in both Africa and South America offer examples suggestive of reciprocal specialization of function- ally matched characters in plants and associated ants. In this category are matches between the dimensions of ants and the prostomas of their plant associates (McKey 1991, Davidson and Fisher 1991), and between food provisioning by plants and the foraging and pruning behaviors of their ants (Davidson et al. 1988). Though suggestive, the data are not usually sufficient to pass a rigorous test, especially in view of our poor knowledge of phylo- genetic relationships (McKey 1991 ). The second aspect of coevolution is association by descent (Mitter and Brooks 1983). If ant-plant relationships have persisted and diversified as the associated lineages underwent successive specia- tional events, their phylogenies should be congru- ent. If, on the other hand, events such as host- switching and secondary exploitation of preexist- ing ant-plant mutualisms are frequent, there will be no close correspondence between ant and plant phylogenies. Interspecific hybridization of plants and/or ants will produce yet a third pattern, reticu- late evolution. Janzen (1974a) concludes (without rigorous phylogenetic analysis) that the neotropical ant-acacias do not form a tight phyletic group, and postulates that one species may capture ant-adapted traits from another via introgression. Ross ( 1 98 1 ) came to similar conclusions regarding African ant- acacias. Aside from the two groups of Acacia, there is little information to evaluate the possible role of hybridization in the diversification of ant-plants. Moreover, Janzen' s observations might be explained alternatively by genotype-environment interactions. Thus, evolved associations of ants with one acacia lineage could have increased the selection intensity for myrmecophy tism in other ( possibly preadapted ) Volume 2, Number 1, 1993 43 lineages, perhaps because ants occasionally colo- nized these unspecialized hosts. Of the relatively small number of taxa which have produced modest to extensive radiations of ant-plants or plant-ants, taxonomic uncertainty pre- cludes any examination of the question of associa- tion by descent in all but a few cases. And in no case do we have equally robust phylogenies in both ants and plants. By far the best example is Ward's (1991) study of associations between plants and pseudomyrmecine ants, represented by Pseudo- myrmex and Myrcidris (Ward 1990) in the Neotropics, and by Tetraponera in Africa, Asia and Australasia. Specialist plant-ants appear to have arisen at least 1 2 times in this sub-family, on a wide range of hosts. Most of these events have produced only one or a few species of plant-ants, associated with a comparably small number of host species. Such small radiations offer limited opportunity for association by descent. In some cases, apparently secondary pseudomyrmecine colonizations of pre- existing ant-plant mutualisms have given rise to a small number of species on Cordia, Pleurothyrium and possibly Cecropia (Ward 1991), all of which are predominantly associated with other ants (Allomerus, Myrmelachista and Azteca, respec- tively). The hosts of pseudomyrmecines do include, however, three plant genera with large numbers of ant-plant species. Each of these (neotropical Aca- cia, Tachigali, and Triplaris) is associated with a different monophyletic group of Pseudomyrmex. Do these more extensive radiations offer evidence of association by descent? Ward ( 1991 ) concludes that at the species level, they do not. First, within each of these groups there is no pairwise specificity of ant and plant species. Not surprisingly, there is no clear pattern of cospeciation. Although in each of these three cases, the plant lineage seems to have evolved in concert with the ant lineage, the pattern of associations suggests host shifts within a taxo- nomically restricted guild of ants and plants, rather than cospeciation. Furthermore, each of these plant groups also harbors ants from at least one other lineage of Pseudomyrmex. Even in these extensive radiations from associated ancestors, coevolution seems to have been diffuse, corresponding to the guild coevolution or ecological replacement hy- potheses (Howe and Westley 1988), rather than to a hypothesis of pairwise coevolution. Relationships of various plant-ants to neotropical Cecropia paint a somewhat similar picture. Within ponerines of the genus Pacliycondyla, four prob- able Cecropia specialists represent at least three separate origins of specialization on this host ge- nus. Independent origins include species near both P. villosa (Fabricius) and P. unidentata Mayr (J. Longino, personal communication) as well as Pacliycondyla sp. nov. in Panama. Of these, the first two species appear to be stem parasites. Their small, secretive colonies show little activity on host surfaces, though workers of at least the species near P. villosa harvest Mullerian bodies and locate en- trances at prostomas (J. Longino, personal commu- nication). At present, no data suggest specificity of host range within the genus Cecropia. In contrast, Pacliycondyla sp. nov. appears to have a highly specialized relationship with C hispidissima, which produces especially large, hard and purple Mullerian bodies (Davidson and Fisher 1991, B. Fisher, per- sonal communication). A close phylogenetic rela- tionship between this ant and the Peruvian P. luteola cannot yet be ruled out (W. L. Brown, personal communication). Colonies of the latter ant occur only on C. (prov.) "tessmannii", whose relation- ship to C. hispidissima is currently uncharacterized. The affiliations of Pacliycondyla sp. nov. and P. luteola with their respective hosts are the most likely candidates for pairwise coevolution between ants and Cecropia trees, and the evidence is still weak. Even if ant and plant phylogenies turn out to be congruent here, and if speciation events are determined to have been synchronous in ant and plant lineages, any postulated cospeciation would appear to have been minimal, based on the small number of Pacliycondyla specialized to Cecropia. Three other ant genera provide support for mul- tiple independent colonizations of Cecropia. The genus Camponotus includes at least two host gen- eralists, C. balzani Emery in southeastern Peru, and an unnamed species of Camponotus sub-genus Pseudocolobopsis in northern Peru( Davidson, un- published; R. Snelling. personal communication). Multiple radiations of specialized Azteca (Longino 1989b, 1991a and b) were mentioned above. Al- though phylogenies are not yet defined within ei- 44 Journal of Hymenoptera Research ther ant genus, the overlapping and generalized host ranges of closely related ant species argue against cospeciation as the major mechanism by which diversity is generated. Finally, at least one Crematogaster species ( near C. curvispinosa Mayr, J. Longino, personal communication ) appears to be a specialist on Cecropia in northeastern Peru (vie. Genaro Herrera), but inhabits at least several differ- ent hosts within the genus (D. Davidson, personal observation). With specialized symbionts repre- senting four of the five sub-families of plant-ants, and multiple origins within at least three ant genera. Cecropia presents a strong case for the ease with which taxa of generalized stem-nesting ants have colonized myrmecophytes over evolutionary time. Like Pseudomyrmex and Tetraponera, many other plant-ant genera are associated with numer- ous, unrelated plant hosts (Appendix 1). Of 31 plant-ant genera (including various subgenera of Camponotus), only 1 1 are known from a single host genus, and three of these are records for species whose specialization as plant-ants (column 7) re- mains in doubt. As in pseudomyrmecines, these broad generic host ranges are probably due both to multiple independent origins of the plant-ant habit within the ant genus, and to secondary colonization of additional hosts by plant-ant species. However, the taxonomic information necessary to distinguish between these possibilities is lacking. Allomerus is a particularly intriguing case. All known species are specialist plant-ants. Unless we assume that non-specialist Allomerus once existed but are now all extinct ( the genus has no fossil record [Holldobler and Wilson 1 990] ), then the host range of this genus (seven plant genera in five families) is due to secondary colonizations and host shifts. Perhaps the clearest evidence against cospeciation is offered by those cases in which a prerequisite for cospeciation, host-specificity, is not fulfilled. Several plant-ant species are associ- ated with two or more quite unrelated hosts. At least three specialist plant-ant species of Pseudomyrmex occupy more than one plant genus (Ward 1991), with P. viduus F. Smith recorded from 5 genera in as many families. Aphomomyrmex afer Emery is associated with Vitex ( Verbenaceae) and Leonardoxa (Fabaceae) (R. Snelling, personal communication). Technomyrmex (formerly Engramma) kohlii is associated with five genera (Colo, Scaphopetalum, Canthium, Diospyros and Delpydora) belonging to four families (Bequaert 1 922; R. Snelling, personal communication). These appear to be cases in which secondary colonization of ant-plants has occurred several times. At least one other case, however, does suggest association by descent. African Leonardoxa in- cludes two myrmecophytes, which cladistic analy- sis has shown to be sister species (McKey 1991 ). They are inhabited by Aphomomyrmex afer and Petalomyrmex phylax Snelling, respectively, the only two African representatives of the formicine tribe Myrmelachistini. Though these two ants are obviously closely related (Agosti 1991), further taxonomic work will be required to determine whether they are sister species or relicts of formerly diverse genera in which all congeners have gone extinct. Habitat Specialization and the Generation of Diversity in Ant-plant Symbioses Our analysis indicates that cospeciation in lin- eages of plants and of host-specific ants has been infrequent at best. Ant-plant pairs may be co- evolved, but associations seem to be shuffled or broken frequently, rather than diversified in con- cert via cospeciation. Pairwise coevolution thus can account for little of the diversification of these symbioses. How then have symbiotic ant-plant associations diversified? Mounting evidence sug- gests that evolutionary interactions in these sys- tems, in both Africa and the Neotropics. correspond more closely to two other models of coevolution, not mutually exclusive, the guild coevolution hy- pothesis and the ecological replacement hypothesis (Howe and Westley 1988). These hypotheses en- visage diffuse evolutionary interactions among sympatric guilds of associated organisms. Specia- tion may be accompanied by shifts in patterns of host associations, producing new mixes and matches. In these guilds, one member may replace another as the predominant associate of a particular member of the other guild. Guilds are also open. New ants may colonize pre-existing ant-plant mutualisms, perhaps displacing or completely re- Volume 2, Number 1, 1993 45 placing other ants, and new plants may join a guild of ant-plants. We postulate that habitat-dependence in the outcome of different ant-plant interactions has been the principal force driving host shifts and ecologi- cal replacements within these guilds. Thus, the main obstacle to species-specificity and pairwise coevolution of ants and plants has at the same time facilitated diversification by other mechanisms. Host plant quality, as recognized by ants, may vary more with habitat than with host species. Thus. Janzen (1966) has called attention to disparities in the habitat associations of P. nigrocinctus (Emery) and P. spinicola Emery (= P. ferruginea), though the two closely related ( Ward 1 99 1 ) species coexist locally. In some parts of their ranges, these two species also coexist with P.flavicornis F. Smith ( = P. belti), which has yet a different pattern of habitat association (Janzen 1983). In another example, distributions of obligate Cecropia ants, both within and across genera, are usually more responsive to habitats than to host species (Harada and Benson 1988,Longino 1989b, 1 99 la and b, Davidson etal. 1991 ). As is the case for acacia-ants, the conse- quent mixing and matching of ants and Cecropia species may favor diffuse rather than pairwise coevolution. Likewise, effects of different ants on plant fitness may vary with habitat, for example, if the quality of defense against herbivores mattered less under favorable than unfavorable resource regimes. Thus, genetic differentiation may be associated more frequently with habitat specialization, both in plants ( Davidson and Fisher 1 99 1 ) and in ants, than with specific identities of associates. However, habitat-dependence may still drive a type of cospeciation. For example, a plant and an associ- ated ant may have parallel genetic responses to environmental variation, both of them diverging from conspecifics in a different habitat. Or, genetic differentiation in one symbiont, driven by habitat specialization, may induce divergence in its associ- ate (Thompson 1987). The likelihood of such events, in which both ant and plant remain associ- ated while undergoing habitat-related divergence, may depend on guild diversity. Thus, when an ant- plant colonizes a novel environment, poor success of the usual ant associate certainly provides selec- tive pressure for adaptation of the ant to the new habitat. But it also provides opportunities for the establishment of other ant species. The richer the local guild of plant-ants, the greater the likelihood that a member of the guild will establish success- fully, replacing the usual associate and preventing its specialization for the novel habitat. In depauper- ate guilds, preadapted ants are fewer, and the usual associate may be more likely to persist and adapt to the novel environment. A possible example is the relationship between Leonardoxa spp. and their Petalomyrme.x and Aphomomyrmex ants. Plausi- bly a case of cospeciation, this system involves a small number of ant and plant species (McKey 1 99 1 ). Neither the two plants nor the two ants ever occur sy mpatrically , and few other myrmecophy tes and domatia-inhabiting ants share their habitats. Perhaps pairwise specificity and cospeciation are more likely to occur in modest and geographically limited radiations such as these, where taxonomic poverty of sympatric guilds of ant-plants and plant- ants offers little scope for host-switching and sec- ondary colonization. The latter processes may dominate in species-rich guilds. If our hypothesis is correct, it would suggest that diversity begets diversity due to genotype-environment interactions in tropical ant-plant symbioses. EVOLUTIONARY TRENDS IN SPECIES REPLACEMENTS WITHIN PLANT-ANT GUILDS Host-switching, secondary colonization, and eco- logical replacement seem to be the predominant modes by which ant-plant associations are modi- fied. Once a new association is forged, it is likely to engender selection on one or both partners, and to give rise to evolutionary diversification. But how do new associations form and spread? What is their effect on preexisting associations'? Can we recognize patterns in the radiation of plant-ants and ant-plants? Once again, it may be possible to understand the evolutionary dynamics of ant-plant associations in the context of competitive interac- tions among ants, and habitat-dependence in the outcome of ant-ant and ant-plant interactions. While many species replacements may have occurred without perceptible trace, contemporary systems in which ant-plants are associated with multiple unre- 46 Journal of Hymenoptera Research Table 2. Earliest fossil records of ants for genera (worldwide) in which specialized plant-ants have evolved (summary excerpted from Holldobler and Wilson 1990): A = Arkansas amber (USA, middle Eocene); Ba = Baltic amber (northern Europe, early Oligocene); Br = Britain (Oligocene); Do = Dominican amber (Dominican Republic, late Miocenea); F = Florissant shales, Colorado, USA, Oligocene); Sh = Shanwang shales (China, Miocene); Si = Sicilian amber (Sicily, Miocene). Sub-family and tribe Genus Earliest fossil find PONERINAE Tribe Ponerini Pachycondyla Early Oligocene PSEUDOMYRMECINAE Myrcidris No fossil record Pseudomyrmex Oligocene Tetraponera Early Oligocene MYRMICINAE Tribe Cephalotini Zacryptocerus Late Miocene Tribe Crematogastrini Crematogaster Miocene' ' Tribe Leptothoracini Leptothorax Early Oligocene Tribe Pheidolini Pheidole rw D,F Oligocene Tribe Solenopsidini Allomerus No fossil record Solenopsis Late Miocene Tribe Tetramoriini Tetramorium No fossil record Tribe Dacetini Strumigenys No fossil record Tribe unclassified Cataulacus Miocene Podomyrma No fossil record Atopomyrmex No fossil record DOLICHODERINAE Tribe Tapinomini Anonychomyrma No fossil record Axinidris No fossil record Azteca Early Miocene Tapinoma Miocene Technomyrmex Miocene' ' FORMICINAE Tribe Plagiolepidini Plagiolepis Early Oligocene a' Tribe Myrmelachistini Aphomomyrmex No fossil record Cladomyrma No fossil record Myrmelachista No fossil record Petalomyrmex No fossil record Tribe Camponotini Camponotus Early Oligocene a' Note added in proof. Although Holldobbler and Wilson ( 1 99 1 ) date the Baltic amber as late Oligocene, more recent work summarized by Kirsshna and Grimaldi ( 1991 ) suggests an earlier estimate. We use the latter date because it is conservative in relation to our hypothesis. Volume 2, Number 1, 1993 47 lated plant-ants may offer examples of species replacements in progress. The various ant associ- ates of myrmecophytes usually occupy different places in a competitive hierarchy. An understand- ing of theircompetitive relationships, and how they coexist today, should provide insights into the ecological mechanisms that have driven their evo- lutionary histories. Without more phylogenetic evidence than exists today, we have only a snapshot of a process in motion, and cannot know its direction with cer- tainty. Nevertheless, we attempt a provisional distinction between original associates and second- ary colonists of several ant-plant associations. First, we focus on two ant lineages which seem to have played predictable and frequent roles in the eco- logical replacement of primary associates. We then examine likely causes of such pattern, based on what is known of the biology and competitive relationships of the ants involved. Generalizing from these examples, and referencing the fossil record, we propose a hypothesis of taxonomic progressions within lineages of plant-ants. This hypothesis, combined with information on the geo- logical history of mesic-forest environments in different tropical regions, leads to new interpreta- tions of intercontinental differences among ant- plant symbioses. Directionality of Species Replacements The primary and secondary associates of many myrmecophytes can be very difficult to distinguish (Ward 1991). Nevertheless, patterns in the biogeo- graphic and taxonomic distribution of host associa- tions in some ant-plant systems suggest that myrmecophytes have been colonized recently by unspecialized arboreal ants or by host-shifting plant- ants, resulting in partial or complete replacement of a prior ant associate. In none of the examples that follow is the evidence for directionality conclusive. Nevertheless, taken togetherthe evidence is strongly suggestive, and the approach has enabled us to propose testable hypotheses and to define critical points where data required to test these hypotheses are lacking. Crematogaster as Secondary Associates of Myrmecophytes. — Several ant-plant relationships provide indications that ants of the genus Crematogaster have partially or completely re- placed prior ant associates of the host plant. First, the pattern of ant associations with the two African Barteria species suggests that ancestral host rela- tionships may have involved Tetraponera ants. For T. aethiops ( F. Smith ) and T. latifrons ( Emery ), two host-specific associates of B.fistulosa Mast. ( Janzen 1972), taxonomic isolation from other sections of the genus suggests comparatively ancient origins for the association (P. Ward, personal communica- tion). Tetraponera has not been found to inhabit the other described species of Barteria, B. nigritana Hook, f., which instead houses an apparently unspecialized Crematogaster. The latter associa- tion may have arisen via secondary colonization of hosts in the more disturbed, light-rich, coastal scrub sites frequented by this plant species. Interestingly, while B. fistidosa is occupied by its specialist Tetraponera in forest light gaps, it too occurs with unspecialized Crematogaster'm large, human-made clearings in coastal forests of Cameroon (D. McKey, personal observation). Second, although Crematogaster spp. are pres- ently the numerically dominant associates of East African ant-acacias, Tetraponera ants may have been the original inhabitants. Invasion of East African acacias by Crematogaster, which gener- ated two new specialists on Acacia, may have largely pushed the weakly competitive pseudomyrmecine into marginal high-elevation sites (Hocking 1970). At lowerelevations(ca. 900 m), T. penzigi (Mayr) appears to be competitively subor- dinate to Crematogaster mimosae (Santschi) and C. nigriceps Emery, and has exclusive possession of only 0.7 % of the trees. At higher elevations, it maintains control of up to 8.5 % of host trees. In sites where it cooccurs with the two Crematogaster, the pseudomyrmecine appears to persist mainly in unoccupied parts of Crematogaster-occwpied trees. There it ensures exclusive occupancy of stipular swellings by boring entrance holes too small to accomodate Crematogaster, and by plugging or protecting these entrances with carton baffles. Asian Macaranga may be another case where contemporary numerically dominant Crematogaster ants have largely replaced the original inhabitants. Poorly known associations occur between two 48 Journal of Hymenoptera Research Camponotus species [provisionally subgenus Colobopsis] etadboth Macaranga griffithiana M.A. and Mocaranga puncticulata Gage (Fiala et al. 1990). Each of these hosts grows principally in swamplands (Whitmore 1973 and 1975), marginal habitats where rates of plant growth and supply of ant resources are likely to be reduced. Finally, one Crematogaster lineage may also have replaced another. Thus, Macaranga hosts in some undis- turbed primary forests are occupied by a species with black workers and 11 -segmented antennae, whereas hosts of forest and riverine edge typically contain any of an unrelated complex of species with yellowish workers and 10-merous antennae (D. Davidson, personal observation). Despite habitat segregation under natural conditions, a mixture of the two ant lineages occurs in the extensive Macaranga forests left after logging. Clearly, in view of the habitat specificity of both myrmecophytes and their ants, the rapid conver- sion of primary forests can be expected to alter these symbiotic associations greatly in future years. In the Neotropics, unspecialized Crematogaster are recorded as clear newcomers and secondary associates of several older ant-plant relationships, including those between Pseudomyrmex and Triplaris (Davidson et al. 1988; Oliveira 1987), Pseudomyrmex and Acacia (Janzen 1983), and Azteca and Zacryptocerus with Cordia alliodora (R. Carroll, personal communication). These Neo- tropical examples include no obvious case in which colonization by Crematogasterhas led to complete replacement of a prior associate, and American Crematogaster have only rarely evolved into spe- cialist plant-ants. Included in the latter category are only the Crematogaster cf. victima of many neotropical leaf-pouch myrmecophytes, and a de- rivative of the opportunistic and widespread C. curvispinosa on Cecropia in northeastern Peru (D. Davidson, personal observation). Azteca as Secondary Associates of Neotropical Myrmecophytes. — In species richness, Azteca are the preeminent competitive dominants among New World plant-ants (Appendix 1 ), and play ecological roles analogous to those of Crematogaster in many Old-World systems (Carroll 1983). Like Crematogaster, they may be displacing subordi- nate species in many relationships. For example. both Crematogaster and Azteca ants displaced Pseudomyrmex dendroicus when permanent wire bridges were made between the host trees and neighboring vegetation (Davidson et al. 1988). Moreover, as we also suspect for Old-World Crematogaster. some displacements of primary associates by Azteca may have been so thorough that distinguishing contemporary from prior asso- ciations is fraught with uncertainty. For example, ants of the genus Azteca are the numerically pre- dominant associates of myrmecophytic Cecropia today, but associations of Cecropia with other ants, such as Camponotus and Pachycondyla, may be older. Each of these latter genera includes species which are Cecropia specialists, and in both cases ongoing competition with Azteca may exclude them from riverine and other riparian habitats, where Cecropia is most abundant and fast-growing (see above, Davidson and Fisher 1991). Replacements may also be occurring within the genus, Azteca. In Amazonian Peru, Azteca ovaticeps and its relative, A. alfari appear to be relative newcomers, dominating contemporary Cecropia populations along riverine and forest edge. The two species are closely allied to ants of other early successional ant plants (Longino 1991b). These ants include A. foreli Emery, which inhabits live stems of a variety of rainforest trees, and A longiceps Forel, from mid-elevation Triplaris of the Costa Rican Pacific coast. Still other representatives of this species-group occur on Cordia alliodora. Thus. A. ovaticeps and A. alfari may have originated during a comparatively recent host switch onto Cecropia. In support of this conjecture are rare observations of apparent mistakes in colony found- ing behavior. Queens of A ovaticeps occasionally attempt to enter Cecropia membranacea by bur- rowing into the trichilia, rather than into prostomas, even though suitable prostomas are available in uncolonized internodes (D. Davidson, personal ob- servation). The arrival of A. ovaticeps may have driven A «».v/ra//.s' out of riverine environments and deeper into the forest, where it persists on a variety of forest light-gap Cecropia species (see above; Davidson and Fisher 1991 ). Azteca australis could itself be a secondary colonist. A member of the A muelleri species complex, it is likely descended from generalized Volume 2, Number 1, 1993 49 carton-building ancestors with well-defended cen- tral nest sites (Longino 1991a and b). Members of this group still maintain carton masses inside the boles of their hosts (Longino 1991a). Ants in this species complex may have gotten their first foot- hold on myrmecophytic Cecropia by building external carton nests on hosts whose prior residents (possibly Camponotus and Pachycondyla species) had died. Analogously and in contemporary times, Azteca may be invading other myrmecophytic associa- tions. In the Manu National Park and Tambopata Reserve of southeastern Peru, at least two carton- building species (probably A. uleiForelvai.cordiae Forel and A. traili [Emery] var. tococae Forel) are residents of trichome myrmecophytes Cordia nodosa and Tococa spp. (Appendix 1). Queens of both ants initiate their colonies inside domatia covered by protective hairs, and their incipient colonies exhibit host-plant fidelity. Nevertheless, larger, established colonies not only leave their hosts regularly to forage, but build satellite nests (often as ant-gardens) on neighboring trees. These ants also prune trail systems through the protective stem trichomes. On Cordia, Azteca ants occur mainly on hosts in environments of unusually high light intensity, and conspecific trees in the primary forest understory are occupied by Allomerus. If we are correct in assuming that plants with long, dense and erect pubescence became myrmecophytes in the context of persistent occupation by tiny and competitively subordinate ants, then larger- bodied, aggressive and dominant Azteca appear to have both restricted the distribution of Allomerus, and perhaps eliminated the former residents of Tococa. Although Tococa is colonized occasionally by timid Crematogaster cf. victima and a species of Solenopsis, we have never found established colo- nies of these ants on the Tococa of southeastern Peru. Identifying and Characterizing Dominants Crematogaster and Azteca are the two genera for which biogeographical and phylogenetic infor- mation is most suggestive of a frequent role as secondary colonists in species replacements among plant-ant guilds. They are also the preeminent competitive dominants in the arboreal ant faunas of Africa and Asia, and New World tropics, respec- tively. Isolated from these continents, the Austra- lian tropics (including New Guinea and associated islands) contains a unique set of competitive domi- nants and relative newcomers to ant-plant symbio- ses. Among these ants (all dolichoderines) are two genera previously classified as Iridomyrmex (Shattuck 1 992b), but now considered to be distinct taxa and endemics of either the Australian {Anonychomyrma) or Oriental and Australian re- gions (Philidris). Also included are pantropical Technomyrmex (a single species of which is appar- ently native to the New World, Shattuck, 1992a). Several other kinds of evidence substantiate the inferential evidence about the relative competitive abilities of ants involved in ant-plant symbioses. Field experiments have demonstrated that Crematogasterand Azteca are the principal formicid enemies of New World Pseudomyrmex on Triplaris (Davidson et al. 1988, see also Oliveira 1987). Furthermore, both host-plant fidelity and pruning of host-plant neighbors are indicative of weak com- petitive ability (Davidson et al. 1988, 1989) and occur with some frequency in Pseudomyrmex, Tetraponera, Pheidole, Camponotus, and in vari- ous myrmelachistines. In contrast, these behaviors are atypical of Crematogaster, Anonychomyrma, Azteca, and Technomyrmex (Appendix 1, column 4). Rare occurrences are limited to early succes- sional environments where vines and competitors are particularly threatening, as for the Azteca of New World Cecropia, and Crematogaster of Asian Macaranga. They can also characterize ants which are unusually timid for their genera, as are the Azteca exhibiting host-plant fidelity on pubescent species of Triplaris. Implicit in their capacity to invade myrmecophytes previously dominated by other ants, secondary colonists likely owe their success to evolutionary novelties which have enhanced their colonizing and/or competitive abilities. The genera listed above as competitive dominants are alike in possessing potent exocrine products which help to convey competitive superiority in interactions with other ants (Blum and Hermann 1978, Buschinger and Maschwitz 1984). Structural characteristics of waists and gasters permit workers to elevate gasters 50 Journal of Hymenoptera Research and direct toxins toward enemy ants. The same adaptations can be effective against potential nest raiders, as when Crematogaster workers seal hol- low stem nests with protruding gasters bearing poison droplets on modified spatulate stings (Forel 1928). Many dominants are also carton-builders, which monopolize resources in the arboreal zone by constructing primary or ancillary nests over Homoptera and other localized food sources such as extrafloral nectaries. These traits contribute to the capacity of domi- nant ants to monopolize "promiscuous" plant re- wards such as EFN's and surface-feeding Homoptera, which are either totally unprotected or only partly secluded beneath clasping or folded stipules of myrmecophiles. Thus in Borneo, Crematogaster species dominate the exposed EFN*s of most individuals of myrmecophilic Endospermum (Euphorbiaceae), Ryparosa (Flacourtiaceae), and Macaranga aetheadenia Airy Shaw (D. Davidson, personal observation). Crematogaster are also preeminent among visitors toofhermyrmecophilic Malaysian Macaranga spp. (Fiala and Maschwitz 1991). In New Guinea, scale-tending Crematogaster are the numerically predominant inhabitants of the stout hollow stems of weedy Nauclea (D. Davidson, personal observa- tion). Myrmecophiles with nectaries partly se- cluded beneath folded or clasping stipules include New Guinea Arch idea dron (Fabaceae) and Orien- tal Shorea (Dipterocarpaceae), both often domi- nated by Teclmomyrmex ants (D. Davidson, per- sonal observation, Tho, fide Maschwitz and Fiala, in press). By sealing off the folded stipules with carton, these ants may restrict their competitors' access to EFN. An ability to monopolize externally located food resources may also confer a competi- tive advantage to dominants on myrmecophytes which produce such resources. This result would be especially likely if evolutionary interactions of the plants with prior ant associates had led to increased size and/or number of EFN's and food bodies, or otherwise increased the rate of food production to a level at which the plant becomes attractive to competitive dominants requiring high rates of resource supply. Processes of Species Replacements How have secondary colonists managed to re- place primary associates with highly evolved mecha- nisms for locating and exploiting hosts? Even very aggressive and dominant ants may have difficulty evicting weakly competitive ants, once the latter have established their colonies. Thus it seems likely that many secondary colonists first achieved access to myrmecophytes by occupying hosts whose usual partners were absent for one reason or an- other. For example, like the Azteca discussed above, some Crematogaster could have gained a preliminary foothold on myrmecophytes by build- ing carton nests on plants which had outlived their ant colonies. Early stages of this scenario may be represented in the New World associations of Crematogaster with myrmecophytic acacia spe- cies in second growth environments ( Janzen 1 983). Although Crematogaster are apparently unable to replace Pseudomyrmex on smaller acacias, they can resist colonization by the latter species on larger acacias which have lost their former Pseudomyrmex colonies. The more characteristic ant associates may be absent for other reasons. First, by opening domatia to feed on ant larvae, vertebrate predators of ants may make these domatia unsuitable for continued habitation by weakly competitive species. For example, after swollen internodes of Cordia alliodora are opened by woodpeckers, unspecialized Crematogaster often move in and employ carton baffles to seal breaks in the domatia (R. Carroll, personal communication). Second, older domatia are frequently abandoned by the usual residents, as colonies move to follow new growth and produc- tivity. In Cecropia (Davidson et al. 1 99 1 ), Remijia (Benson 1985), Leonardoxa (D. McKey, personal observation), Endospermum, Korthalsia, and other genera (D. Davidson, unpublished), such aban- doned domatia are often occupied by unspecialized ants, which gain at least protected nest sites if not food (Davidson and Fisher 1991, Longino 1991a). A possible case of progressive specialization in such ants may be seen in the unnamed Crematogaster species which occupies Cecropia near Genaro Herrera in Loreto, Peru (D. Davidson, personal observation). Related to C. curvispinosa Volume 2, Number 1, 1993 51 (J. Longino, personal communication), it is appar- ently descended from generalized stem-nesters, ratherthan from acarton-building lineage. Special- ization on Cecropia could have been favored by selection sharpening the host-finding abilities of foundresses which occasionally colonized the woody bases of forest-gap plants, and eventually evolved to recognize Mullerian bodies as food. Third, the typical ant associates may fail to either colonize or to persist on hosts in inappropri- ate habitats. Small forest light gaps are marginal for western Amazonian Cecropia, and comparatively low colonization rates on isolated and inconspicu- ous gap plants appear to have provided safety for refugees from riverbanks, as well as opportunities for in situ colonization of this host genus. All four little-known genera of Cecropia ants persist princi- pally in forest light gaps. Both Camponotus balzani and Pachycondyla luteola colonize riverine plants, but rarely persist there, being excluded by Azteca. In contrast, species of Crematogaster and Camponotus (Pseudocolobopsis) occur on several light gap species at Genaro Herrera, but apparently do not even colonize plants of riverine and forest edge. Their relationships with Cecropia may have evolved in situ. Alternatively, past competition with Azteca may have led to a shift in their habitat preferences. Finally, colonists may also gain a foothold at the latitudinal or elevational limits of ant-plant asso- ciations. Latitudinally. the genus Triplaris ranges northward into Mexico; in southwestern Chiapas near Mapastepec, it is occupied by a variety of apparently unspecialized species of Azteca, Crematogaster and Pseudomyrmex, rather than by the more typical specialized pseudomyrmecine as- sociates (D. Davidson, personal observation). At least one specialized Cecropia ant, dry forest A. coeruleipennis Emery, may have evolved in situ in Central America (Longino 1989a and b), a periph- eral and comparatively species-poor region within the overall distribution of Cecropia. These events might well have resulted from independent second- ary colonizations of a host which reached Central America from South America in advance of its typical ant symbionts, or which colonized habitats unsuited to the usual associates. Elevational segregation among plant-ants of par- ticular hosts suggests that new colonizations might occur at the elevational limits of species distribu- tions. In the lowlands of Cameroon, myrmecophy tic Leonardoxa consistently house one of two closely related myrmelachistine ants. Petalomyrmexphylax or Aphomomyrmexafer, depending on host species (McKey 1991). However, in submontane forests of the Rumpi Hills (500-1700 m), where neither of these ants occurs in association with Leonardoxa, the plants are inhabited by a bewildering array of other ants, including at least two species each of Crematogaster, Axinidris and Technomyrmex, and one species each of Tapinoma and Leptothorax (R. Snelling, personal communication). Some of these ants are known not to be host-specific, and they may be secondary colonists of a preexisting asso- ciation of Leonardoxa with myrmelachistine ants, although firm conclusions on directionality of this shift must await further work. Finally, in the Neotropics, altitudinal replacements should be com- mon at the periphery of the Andes. Although we know of no published data to test this prediction, Longino (1991b) relates that the ranges of some AzJeca residents of Cecropia segregate altitudinally, with some species occurring as high as 2000 m in elevation. As secondary colonists of myrmecophytes be- come increasingly specialized for exploiting their new hosts, selection should enhance the host-find- ing abilities of these species. With their priority-of- colonization eroded, primary associates may even- tually be displaced to marginal habitats or replaced altogether. Taxonomic Progressions Within Plant-Ant Lineages Since ant-plant symbioses have been shaped by repeated evolutionary colonizations and strong com- petition among ants, major taxa of plant-ants might be expected to exhibit regular taxonomic progres- sions in species distributions and characteristics. Similar progressions have been described for adap- tive radiations in several well-studied animal groups, including ants (Wilson 1959a and 1961), carabid beetles (Erwin 1985), and birds (Ricklefs and Cox 1972; Diamond 1986). These accounts are related 52 Journal of Hymenoptera Research in their emphasis on competition as the force driv- ing evolutionary trajectories in animal lineages. Wilson's seminal exposition of the "taxon cycle" in Melanesian ants proposes that ants invade new geographic areas principally via marginal habitats where competition from other ants is reduced. From this tenuous foothold, and driven by arrivals of new and more dominant species, they diversify and evolve competitive strategies which eventually enable their invasion of more species-rich forest habitats. In apparent contrast, Erwin's recent ac- count of "taxon pulses" in carabid beetles proposes that young carabid taxa first appear in productive and central moist equatorial habitats. There, they force the specialization and migration of older taxa into less competitive peripheral latitudes and habi- tats. Apparent disparities in the phrasing of Wilson's and Erwin's theories obscure theircommon ground. Both ideas have their roots in Darlington's ( 1957) "centrifugal speciation", whereby intense biotic interactions drive waves of species and higher taxa from tropical to temperate regions. Moreover, whether species originate in new and permissive environments, or as evolutionary novelties in biotically restrictive environments, young species are those with "r-selected" life histories, and gener- alized and expanding distributions. Older, progres- sively "K-selected" species are driven by biotic interactions to increasing specialization and more circumscribed distributions. There they persist by either unique strategies for evading natural en- emies, or by tolerance of unfavorable conditions. Vermeij (1978) has argued cogently for similar evolutionary trajectories in various marine inverte- brate taxa. The evolutionary history of plant-ants strongly suggests similar taxonomic progressions. Three types of evidence support such an interpretation. First, as discussed above, taxonomic and biogeo- graphic patterns in some ant-plant symbioses sug- gest directionality in species replacements, and particular taxa occupy predictable roles as victims (e.g., Pseudomyrmecinae) and agents (e.g., Crematogaster and Azteca) of such replacements. Second, and also discussed above, field experi- ments and observations strongly support interspe- cific competition among ants, often habitat-depen- dent in its outcome, as the principal mechanism of species replacements. Furthermore, roles of differ- ent ants in postulated replacements are consistent with their status (independently determined) in competitive hierarchies. Third, within ant-plant guilds, the postulated replacements of subordinate genera, such as Pachycondyla, Plagiolepis, Camponotus, Pseudomyrmex, and Tetraponera, by dominant genera such as Crematogaster, Technomyrmex, and Azteca, are consistent with the historical sequence in which these taxa are repre- sented in the fossil record (Table 2, based on Holldobler and Wilson 1990, and see below). The diversification of ant taxa began in earnest no later than the beginning of the Tertiary Period (Holldobler and Wilson 1990), and it eventually made ants the most important natural enemies of one another. At protected nests and feeding sites, timid, twig-inhabiting myrmelachistines and pseudomyrmecines, probably among the earliest plant-ants, sought out pubescent plants or insect borings and other cavities of live plants. But in the background, competition was escalating. Evolu- tionary advancements in offensive and defensive weaponry intensified the pressures on timid and secretive plant-ants. As discussed above, evolu- tionary novelties and secondary colonizations ap- pear to have arisen differentially in environments where disturbance favored weedy species with early and high reproductive allocation, superior coloniz- ing ability, and thus priority of access to ant domatia. Here also, high productivity (associated with high light intensities) subsidized rapid colony growth and the evolution of costly chemical weaponry. Individually or in combination, these traits made their bearers formidable enemies of existing plant- ants, driving them into ever more restrictive spe- cialization on one or a few hosts, into marginal habitats, and in some cases into extinction. Eventu- ally, many secondary colonists appear to have partly or completely replaced the primary associ- ates of several myrmecophyte lineages. These secondary associates were often pressured in turn by successive waves of newly evolved dominants. What examples support such a scenario? Myrmelachistine ants provide perhaps the best il- lustration of the fate of an old group of competi- tively subordinate ants, whose members have been driven to suboptimal habitats, to extreme special- Volume 2, Number 1, 1993 53 ization, or to extinction, by dominant ants. As circumscribed by Holldobler and Wilson (1990). following Wheeler ( 1920). this tribe is pantropical and includes six genera, two of which are endemic to each of the major tropical regions (the New World, tropical Africa and the Oriental tropics). In a recent and still incomplete analysis of generic relationships in Formicinae. Agosti (1991) casts doubt on the monophyly of the tribe, placing Cladomyma in a different informal genus-group from all the others. We follow the usual treatment of the tribe, but acknowledge the need for further work to resolve phylogenetic relationships of these ants. Myrmelachistine genera have no fossil record (Table 2), possibly because most have long been specialist plant-ants with restricted ecological dis- tributions. However, they are likely to have been widespread prior to Miocene times, since two ant genera from a tribe (Gesomyrmecini), considered by Wheeler ( 1920) to be closely related (but see Agosti 1991), are represented in early Oligocene Baltic amber (Holldobler and Wilson 1990). One of these, Gesomyrmex, is represented by four extant species of the Oriental region (Wheeler 1929a). They share with the Oriental myrmelachistine Cladomyrma certain similarities, such as reduced antennal segmentation (believed to be a derived character) and worker polymorphism with major, media, and minor workers. Furthermore. G. kalshoveni Wheeler of Java, is recorded as nesting in twig cavities of Artocarpus in primary forest (Wheeler 1929b). These bits of information on an ant genus regarded by Wheeler (1929a) as "living fossils which have undergone no significant modi- fication since the Early Tertiary" suggest that the plant-ant habit may have a long evolutionary his- tory in the Formicinae, currently regarded as hav- ing diverged very early from the basal lineage of the Formicidae (Holldobler and Wilson 1990). In all parts of their pantropical distribution, myrmelachistines appear to have experienced eco- logical contraction. Although no phylogeny is available for the New World genus Myrmelachista, interspecific patterns in its distribution and ecology reveal the likely imprint of past competition. Myrmelachista are often conspicuous leaf foragers in montane forests of Central and South America, where dominant Crematogaster and Azteca ants are largely missing (J. Longino, personal commu- nication). In sharp contrast, congeners of tropical lowlands are stem-nesters with a relatively incon- spicuous presence on leaf surfaces. Among resi- dents of Costa Rican Ocotea, workers of a Myrmelachista plant-ant at 500-700 m elevation (at Rara Avis) do not attack vines (B. Fisher, personal communication), though those of a congener at 50 m in nearby La Selva Biological Station do prune (D. Davidson, personal observation). Finally, in western Amazonia, perhaps the center of neotropical ant diversity (Wilson 1987), Myrmelachista resi- dents of Duroia hirsuta and Cordia nodosa appear to protect themselves not only by pruning vegeta- tion other than potential host plants, and by main- taining extensive clearings ("supay chacras"), but by effectively hiding from larger-bodied ants amid the dense stem hairs of these two hosts. (Morawetz et al. [1992] argue that creation of similar clearings by a Myrmelachista species on Tococa is not a product of past competition. However, this asser- tion is based strictly on the probably valid assump- tion that clearings enhance the light environment and productivity of host plants; it did not stem from any direct test for the effects of competition from other ants [see, e.g., Davidson et al. 1988]). Over- all, the pattern reveals that increasing specializa- tion for resisting dominant ants may have been required for persistence in highly competitive and diverse lowland rainforest faunas. The evolutionary fortunes of myrmelachistines also appear to have declined in the Old World tropics. In Africa, they are represented by only two monotypic genera (Petalomyrmex and Aphomomyrmex). The former is restricted to a single host species and confined to a very small area of Lower Guinea coastal forest. Both species are plant-ants, though interestingly, neither prunes nor inhabits pubescent myrmecophytes. Cladomyrma is one of two myrmelachistine genera known from Asia (with the status of Pseudaphomomyrmex re- maining uncertain), and all five described species are specialized plant-ants (Agosti 1991 ). Some of their hosts (e.g., Saraca) are shared with Crematogaster, suggesting the potential for com- petitive interactions with this group of dominant ants. Furthermore, patterns of host association indi- 54 Journal of Hymenoptera Research cate that Crematogaster may have replaced Cladomyrma in some systems. Thus Cladomyrma persists on Asian Neonauclea, but Crematogaster dominates closely related Myrmeconauclea. Too little is known of phylogenetic relationships among representatives of any of these lineages to draw firm conclusions. Pseudomyrmecines appear to be another rela- tively old group in which the plant-ant habit may be ancient, and in which competitively subordinate plant-ants have been restricted or replaced by more recently evolved, competitive dominants. Tetraponera first appears in fossil deposits in the early Oligocene and Pseudomyrmex in the Oli- gocene (Table 2). The monotypic Myrcidris, a plant-ant whose specializations indicate a long his- tory of association with plants, may be a relict that is the sister group to all other pseudomyrmecines, though other interpretations are possible (Ward 1990). As discussed above, plant-ants of this rela- tively old subfamily are among the most frequent apparent victims of the expansion of younger groups such as Crematogaster and Azteca. Other groups of competitively subordinate ants for which there is circumstantial evidence of re- placement by more recently evolved dominants also occur relatively early in the fossil record. These include Pachycondyla, Camponotus, and Plagiolepis, all of which appear in the early Oli- gocene. Cecropia specialists derived from widely distributed Pachycondyla villosa and P. unidentata (J. Longino, personal communication) are prob- ably more recent secondary colonists, inhabiting mainly older and woody stems abandoned by other ants. At present, no evidence indicates that these are replacing former inhabitants. Allomerus, an- other genus being pressured by contemporary domi- nants, has no fossil record, perhaps because all of these ants have been plant-ants with highly re- stricted distributions. In contrast to these weakly competitive groups, genera implicated as dominant ants and^ secondary or tertiary colonists of existing associations appear to be more recent arrivals. The first fossil records of Crematogaster and Technomyrmex are in the Miocene, and Azteca appears in the early Miocene (Table 2). Taxonomic Progressions and Intercontinental Comparisons of Ant-Plant Symbioses If taxonomic progressions such as those postu- lated above play major roles in transforming ant- plant symbioses over evolutionary time, then long- term evolutionary history assumes an added di- mension as an important factor shaping interconti- nental differences in the nature of ant-plant sym- bioses. Contemporary patterns will reflect the point to which taxonomic progressions in plant- ants have proceeded in a region. The location of this point should depend on the ages of regional mesic-forest communities (to which most ant-plant symbioses are restricted), the traits of the particular dominant and subordinate ants evolved there dur- ing this period, and the degree to which the region is isolated from the products of taxonomic progres- sions begun elsewhere. West Gondwanaland, today represented by its derivative continents Africa and South America, has been considered the cradle of the angiosperms (Raven and Axelrod 1974). Mesic tropical forest and its typical constituents, including plant-ants, have had a long history on both these continents. In Africa, for example, despite climatic vicissitudes and shifts in continental position, a large area of lowland tropical rain forest has persisted unbroken since the Late Cretaceous-Paleocene (75-55 my B.P.) up to the present (Axelrod and Raven 1978). That taxonomic progressions in Africa and South America began with similar starting material, and have continued for about the same amount of time, may account for many of the striking similarities in ant-plant symbioses of these two regions (McKey and Davidson, in press). Interestingly, these two continents share old, competitively subordinate ant groups like myrmelachistines and pseudo- myrmecines. Although these taxa would respond in analogous ways to the later onslaught of domi- nants, the dominants are derived from different genera on the two continents. Whereas in the Neotropics, the preeminent competitive dominants consist of endemic Azteca, Crematogaster domi- nate in the Old World, where they are much more prevalent than in the American tropics (Appendix 1). Volume 2, Number 1, 1993 55 During virtually all the Tertiary, South America was an island continent (Barron et al., 198 1 , Gentry 1982). Perhaps the later appearing dominants, Crematogaster and Azteca, evolved long after di- rect exchange between the two continents (via overland connections or island filter bridges) be- came impossible. Evidence suggests that Crematogaster could be an Old World genus which arrived relatively late in the New World, possibly as part of a widespread tropical Laurasian biota, elements of which could have reached the Neotropics via North America. First recorded in Sicilian amber in the Miocene, the genus is represented in Dominican amber (late Miocene), and might con- ceivably have invaded South America via Panama, a connection in place since the Pliocene (Keigwin 1978, Barron et al. 1981. Marshall et al. 1982). Moreover, species richness of Crematogaster is greater in the African and Oriental tropics than in the Neotropics (Brown 1973), and the genus has evolved numerous specialized plant-ants in the former two regions, but only two such described species in the American tropics. From our sum- mary in Appendix 1, relationships involving Crematogaster account for only 7.6 % of all 66 symbiotic ant-plant relationships listed for the Neotropics, but 39.5 % of 43 associations and 27.3 % of 33 relationships in Africa (including Mala- gasy) and the Oriental tropics, respectively. Based on analyses at the generic level, our calculations fail to take into account the substantial radiations of species within the genus Crematogaster on Asian Macaranga (Appendix 1 ), as well as the nine spe- cies of Crematogaster occurring on African Musanga (though probably none is a specialized plant-ant). No parallel radiations occur in the American tropics. During the Tertiary, while the South American biota was evolving in isolation, there were repeated opportunities for biotic exchange between tropical Africa and tropical Laurasia. The latter region has long harbored mesic tropical forests, though opin- ions vary on whether these forests are as ancient as those of West Gondwanaland (Raven and Axelrod 1974). At the very least, the Oriental tropics were an area of moist, equable climate relatively re- moved from the major vicissitudes of Neogene and later climatic change (Raven and Axelrod 1974). Biotic connections of tropical alliances, at least through the early Tertiary, may account for simi- larities in taxonomic composition of both subordi- nate and dominant plant-ants of the African and Oriental regions (e.g., Tetraponera as well as Crematogaster and Oecophylla). They may also help to explain some possible cases of common ancestry among ant-plant associations of the Afri- can and Oriental tropics (McKey and Davidson, in press). Of the major tropical regions, the Australian tropics (northern Australia, New Guinea, and asso- ciated islands) are outstanding for the geologic youth of their tropical mesic-forest environments. By the Paleocene, Australia was connected with the rest of the world only by a cool-temperate pathway to South America via Antarctica ( Raven and Axelrod 1974). At the start of its northward movement 45- 49 my B.P., what is now tropical northern Australia was all well south of the Tropic of Capricorn, and was still 10 degrees south of its present position by the Miocene, when direct migration from the Asian tropics first became possible (Axelrod and Raven 1972). As for New Guinea, neither it nor its principal antecedents existed prior to about 40 my B.P. Only by the Miocene did it lie close enough to the proto-Indonesian arc to begin receiving large numbers of immigrants from tropical Asia. (How- ever, as vertebrate distributions illustrate, such migration was never directly overland [Axelrod and Raven 1982]). Thus tropical northern Australia and mesic-forest portions of New Guinea have been populated to a large degree by taxa derived from the Asian tropics via intervening islands (Wil- son 1961; Raven and Axelrod 1974). Nevertheless, the contemporary distributions of at least some plant-ants (e.g., Anonychomyrma, see Shattuck. 1 992b) reveal an almost certain origin in Australasia. Tropical forests of northern Australia and New Guinea provide uniquely little evidence for re- placement of older and competitively subordinate ant genera by contemporary dominants. The ori- gins of tropical rain forests in the Australian region have apparently been too recent to have allowed significant radiations of specialized plant-ants in more ancient and weakly competitive ant genera prior to the arrival and expansion of the dominants. If so, this could help to explain why the fraction of 56 Journal of Hymenoptera Research ant-plants obviously specialized as mynnecophytes is so low in the Australian region (column 6 in Appendix 1). Compared to 51.2 % of 39 Neotropi- cal ant-plant genera, 59.4 % of 32 African genera, and 41.4 % of 29 Oriental myrmecophyte genera, only 10.7 % of 28 such genera in the Australian region have conspicuous specializations to attract ants. In the last of these areas, only Endospermum, Canthium and Calamus have convincingly ant- attractive traits (Appendix 1). Present day plant- ants of this region consist principally of dominant species of Anonychomyrma (formerly included in Iridomyrmex, Shattuck 1992b), Technomyrmex and Crematogaster, as well as Philidris on epiphytic mynnecophytes (Shattuck 1992b). These ants oc- cupy only a small number of variously preadapted host genera, where they maintain scale insects at remarkably high biomass, possibly limited by stem volume. Consistent with their status as dominants, they do not exhibit host fidelity in foraging. Neither pruning of host-plant neighbors, nor hiding among dense trichomes is required for persistence of such capable competitors. Two associations with weakly competitive ant genera may also be comparatively recent in origin. The Camponotus of Endospermum obtain their protein not from specially evolved plant structures, nor from protected sources within the stem (e.g., homoptera or the heteroplasias of, e.g., Vitex), but through a form of parasitism of external stem walls, i.e., the induction of heteroplasias from cambium (D. Davidson, per- sonal observation). Moreover, at least one pro- posed myrmecophyte in this genus often occurs without its ants (Airy-Shaw 1980). Similarly. Ward (1991) notes that the unnamed Tetraponera tend- ing coccids in terminal branches of Cupaniopsis has a much narrower geographic range than does its host, and that the symbiosis is apparently young. In attempting to explain intercontinental differ- ences in diversity, it will be extremely difficult to distinguish the relative importances of two major historical factors. These are regional differences in 1 ) the condensation of diversity through competi- tion; and 2) the magnification of diversity, as af- fected by habitat diversity and its effects on rates of evolutionary host shifts and de novo evolutionary colonizations (see above and McKey and Davidson, in press.). CONCLUSIONS Similar selection pressures acting on correspond- ingly preadapted ants and plants have produced strikingly parallel and convergent evolution in the symbiotic ant-plant relationships of different tropi- cal regions. Although current concepts of ant-plant coevolution focus on the pairwise interaction be- tween ant and host plant, these alone cannot ac- count for the patterns we observe. Even in relation- ships where pairwise interactions are undoubtedly strong, multispecies interactions appear to have determined many features of present-day symbio- ses. The most important force driving the evolu- tionary biology of ant-plant symbioses is interspe- cific competition among arboricolous ants. Plants differ in the kinds of resources which they offer to ants, in the rates at which they supply these re- sources, and in traits which influence the relative competitive abilities of foraging and nesting ants. As in other communities structured by competition, plant-ants sort out across plants in ways that are predictable from their particular resource require- ments and competitive abilities and the spectrum of available resources (see also Bristow 1991). In the American, African and Asian tropics, competi- tively dominant ants are associated with the most light-demanding and fast-growing hosts, which supply resources at the rates required to fuel rapid colony growth, interspecific aggression and other traits required for dominance. In contrast, competi- tively subordinate ants are restricted to plants which supply resources at rates too low to support domi- nant ants, or to those from which dominant ants can be excluded by long, dense plant hairs, pruning of neighboring vegetation, or by other ant and plant traits which favor competitively subordinate spe- cies. Competitive interactions among ants deter- mine whether patterns of ant-plant association are sufficiently predictable for strong interactions to shape the evolution of ants and plants. When competitive interactions in plant-ant guilds result in constancy in the pairing of particular ants and plants, reciprocal evolutionary interactions may occasionally give rise to pairwise coevolution. Parallel and convergent selection pressures acted on similar biological material on different tropical land masses. In American, African, Asian and Volume 2, Number 1, 1993 57 Australian regions, the same important preadaptations facilitated evolution of the plant-ant habit in several lineages of arboricolous ants. Fore- most among these traits were the habit of tending Coccoidea, and the differential competitive abili- ties determined by generically typical offensive and defensive weaponry, or by inherent colony growth rates and other life-history attributes. Like- wise, similar sets of plant traits facilitated the evolution of myrmecophytes on different conti- nents. Structures evolved independently of ant- related selective pressures were co-opted repeat- edly as myrmecophytic traits in plant lineages that eventually produced ant-plants. These traits in- cluded both the long, dense hairs typical of many myrmecophyte stems and domatia, and stems strongly thickened as support structures for large leaves, and available as nest sites for opportunistic ants. These similarities in starting material have rendered even more pronounced the striking paral- lel and convergent evolution of ant-plant symbio- ses in the New World and Old World tropics. Diversity of both myrmecophytes and their at- tendant ants appears to accumulate mainly across habitats, rather than biogeographical regions (McKey and Davidson, in press). Among ant- plants, evolutionary diversification across habitat boundaries often appears to reflect the conflicting selection pressures imposed by different plant re- source environments. Like other tropical plants (McKey et al. 1978, Coley 1983), myrmecophytes have responded evolutionarily to particular resource regimes by altering their relative investments in defense versus growth and, perhaps, their relative allocation of different kinds of resources to defen- sive function (Davidson and Fisher 199 1 , Folgarait and Davidson 1992). In turn, ecological and evolu- tionary responses of plants to different resource environments determine the quantity and quality of resource supply to ants. On the whole, then, both partners in ant-plant associations may be more sensitive to habitat than to taxonomic differences among symbiotic partners. Strong competition among mutualists has been proposed as a major factor driving the evolution of specialization in mutualisms (Law and Koptur 1 986), and it could help to account for the origins of many specialized ant-plant symbioses. Neverthe- less, where sufficiently well-studied, phylogenies of plant-ants, together with host distributions of these ants, suggest that pairwise coevolution and cospeciation have been rare. Rather than simple, pairwise ant-plant systems, guilds of interacting ants and plants seem to be the most frequent arena of ant-plant evolutionary interaction. Perhaps as a consequence, plant-switching and secondary colo- nization (rather than cospeciation or some other form of association by descent) may have been the usual processes by which these mutualisms diver- sified. Repeated colonization of myrmecophyte taxa has occurred as unspecialized ants have ex- ploited preexisting mutualisms and specialized plant-ants have switched hosts. Habitat-depen- dence in the effect of associations on fitness of the participants seems to have been the principal force leading to the evolution of new associations. The motor driving such evolutionary opportunities was likely the climatically induced range expansion that placed ants or plants into habitats sufficiently novel to change selection regimes, and to increase encounters with new associates (McKey and Davidson, in press). Regardless of how species originate, a complex mosaic of habitats should help to maintain higher local diversity, with greater species richness of myrmecophytes and/or specialist plant-ants, and a greater number of ant/plant combinations. Since the potential for evolution of new associations via host shifts and secondary colonization depends in part on the sizes of locally interacting ant and plant guilds, high local diversity may lead to higher rates of species origination. Thus, independently of distributional changes driven by varying climates, beta-diversity is likely to have enhanced alpha- diversity. As summarized here, the determinants of diver- sity of plants and ants in these symbiotic mutualisms will likely generalize to other components of tropi- cal floras and faunas. In particular, we expect that diversification of tropical plants has often involved evolutionary adjustments in the amounts and kinds of defenses, in response to habitat differences in absolute and relative availabilities of essential re- sources. Consequently, habitat mosaics related to edaphic factors and incident solar radiation should often determine mosaics in the primary productiv- 58 Journal of Hymenoptera Research ity available to consumer organisms. Habitat spe- cialization to different productivity regimes has likely been important to both the generation and maintenance of diversity in many tropical con- sumer guilds whose member species have strongly overlapping resource requirements (cf., Terborgh 1983 forprimates, and S. Robinson and J. Terborgh, personal communication, for birds). Habitat specialization may frequently also rep- resent the intermediate and final stages of a taxon pulse, in which new, opportunistic, abundant, and widespread species are driven to progressively greater specialization, finer niche differentiation, diminished distribution and abundance, and per- haps even eventual extinction (Wilson 1959a and 1961, Ashton 1969, Erwin 1985, Diamond 1986). If taxon cycles or pulses are general features of animal and plant lineages, they might aid in ex- plaining patterns in the relative abundance distribu- tions of taxa within higher taxa. Dial and Marzluff (1989) have discussed the frequency of "hollow curve distributions", or the overdominance of par- ticular minor taxa within major taxa (subunits/ unit). Thus, the degree of dominance of most dominant taxa is greater than that predicted by a variety of null models based on Poisson processes, random cladogenesis, and simultaneous or sequen- tial resource subdivision, and it is compounded at lower levels of the taxonomic hierarchy. Taxon pulses might regularly give rise to such patterns if the enumeration of taxa at successively lower lev- els of the taxonomic hierarchy (where taxa are more numerous) were more likely to pick up compara- tively rare groups which had recently acquired evolutionary novelties, and which represented in- termediate stages of a taxon pulse. Our analyses of the evolutionary dynamics of ant-plant symbioses here and elsewhere (McKey and Davidson, in press) lead us to propose new hypotheses to explain differences in the diversity of ant-plants and plant-ants across different tropical regions. Such disparities are quite pronounced between the American and African tropical re- gions, where ant-plant symbioses are best under- stood. Previous explanations for differences in the biodiversity of species-rich Neotropical and depau- perate African rain forests have emphasized the contrasting climatic histories of these two regions. Focusing on range contractions during periods of unfavorable climate, these explanations attribute Africa's lower diversity to greater extinction dur- ing the Pleistocene, as Africa's climate became drier, and refugia were fewer than in Amazonia (Raven and Axelrod 1974). We propose that differ- ences between the two regions in the rates of species origination may be at least as important as extinction rates. The relatively stable geological history of most of Africa, including the rainforest zone, has created a landscape with relatively little elevational relief (hence few sharp spatial contrasts in temperature and rainfall), comparatively little edaphic variation, and relatively infrequent and spatially limited fluvial disturbance. In contrast, the Andean orogeny, and subandean tectonic activ- ity, have helped to create a landscape of great elevational, climatic, and edaphic complexity, es- pecially in western Amazonia. This has resulted in a complex and dynamic mosaic of habitats. Colinvaux (in press) suggests that species origina- tion usually takes place when ranges are re-expand- ing during periods of climatic amelioration. If this is so, then in the Neotropics, especially in western Amazonia, range expansion would be much more likely than in the African forest zone to place ants and plants into novel habitats, leading to speciation. the formation of new associations, or both. Although poorly known by comparison, Asian rain forests occur in regions (especially Borneo) where topography is substantially more variable than that of tropical Africa. Aided by forest frag- mentation on numerous island land masses, this topography has contributed to the diversification of several myrmecophyte lineages here. Myrmecophyte diversity in Asia appears to be intermediate between that of the African and Ameri- can tropics. On the other hand, both regions of the Old World tropics may have had the generic diver- sity of their plant-ant faunas condensed, relative to that of the New World, by the comparatively early arrival of a new wave of competitively dominant Crematogaster. The relatively recent origin of rain forests in the Australian tropics (including New Guinea and associated islands) appears to have limited the diversification of myrmecophytes in all but the epiphytic Hydnophytinae ( Jebb 1 99 1 , Huxley and Jebb 1991). In addition, the elaboration of Volume 2, Number 1, 1993 59 myrmecophytic traits, which have evolved so fre- quently elsewhere in associations with weakly com- petitive ants, may have been limited in Australia by the cooccurrence of contemporary dominant and subordinate ants at the time when rain forests were evolving. AC KNOWLEDGEMENTS This work was supported by the NSF grants R1I- 8310359 and BSR-9003079. the Guggenheim Founda- tion, the Christensen Research Institute and the Univer- sity of Utah's Faculty Research Committee (to Davidson) and the Swiss Natural History Society, the National Geographic Society, and the University of Miami (to McKey). We thank R. Snelling for numerous ant iden- tifications, graciously fit into an overburdened schedule, and for helpful conversations about ants. J. Longino and P. Ward made invaluable comments on several previous drafts of the manuscript, and they and R. Snelling made available many of their unpublished observations. Any mistakes remaining are our own. We are also very grateful to M. Hossaert for facilitating our extensive E- Mail correspondence. The manuscript benefitted im- measurably from consultations over recent years with myrmecologists and botanists specializing in particular taxa or floras. These include: C. C. Berg, W. L. Brown, Jr., W. Burger, J. Dransfield, A. H. Gentry, W. Judd, J. Longino, J. Miller. T. Musthak Ali, S. Renner, S. O. Shattuck, J. C. Solomon, C. M. Taylor, H. van der Werff, P. S. Ward, and J. L. Zarucchi. Finally, since ant-plant symbioses are being drastically altered by habitat de- struction around the world, we are particularly grateful for the natural parks and reserves that have permitted us and others to study these interactions in their pristine form. LITERATURE CITED Addicott, J. 1985. Competition in mutualistic systems, pp. 217-247. In Boucher, D. H., ed.. The Biology of Mutualisms. Oxford University Press, Oxford. Agosti, D. 1991. 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Columns: (1) Ant genera (superscript indicates carton-building typical of the genus, though not necessarily of plant-ant species) in biogeographic regions (N) = Neotropical, (E) = Ethiopian, (M) = Malagasy, (O) = Oriental, and (A) = Australian regions. (2) Host taxa have growth forms: T = tree; U = treelet or understory tree; S = shrub; L = liana or vine, R = rattan, B = bamboo and H = hemiepiphyte. Habitats include: b = mountain brooks; e = edge, second growth, riparian environments; g = forest light gaps; 1 = littoral scrub; p = primary forests; s = savannahs or dry forest, and a = aguajals or swamps. (3) Ants nest in domatia comprised of: L = leaf pouches; S = naturally hollow stems; Sp = pithy stems, hollowed by ants; I = swollen internodes; P = swollen petioles or bases of petioles; Ps = petiolar sheath; R = swollen rachi and petioles; St = persistent stipules (in- flated or folded); Sh = persistent spathe; Th = swollen thorns; F = swollen flowering shoots; G = gall-like swellings; C = carton shelters around domatia, folded leaves, and/or hairs or spines; CI = cavity formed by leaf base clasping stem; B = insect borings; O = inflated ocrea (proximal extension of leaf sheath beyond the petiole), A = erect, narrow auricles on each side of petiole, at the terminus of the sheath; Ac = acanthophylls, or basal pinnae reflexed backward to form a secluded cavity at the base of a palm frond; Ga = galleries enclosed by interlocking combs of spines, forming collars on leaf sheaths, and T = vast chambers exca- vated inside tree trunks by ants and partitioned by carton. Plant pubescence: y = domatia and stems bear long, dense hairs or spines, likely to inhibit movements of larger bodied ants; n = such hairs or spines lacking, or s = only a subset of plants have these hairs. (4) Ants prune vines and vegetation around their hosts: Y = obligate for plant-ants in this genus; S = in at least some ant associates of the host genus; F = where known, pruning is facultative, i.e., in the presence of enemy ants; N = not yet reported for the ant genus on this host genus. Host fidelity (foraging predominantly or entirely on the host): y = yes; n = no; i = for young (incipient) but not established colonies. (5) Food types include: P = pearl bodies; B = other specialized food bodies; H = exudates and bodies of homoptera (Coccoidea); E = extrafloral nectar; N = floral nectar; G = uncharacterized exudates of tiny glands; F = fungi; W = lipid-rich and/or protein-rich plant wounds, or heteroplasias caused by traumatic injury by ants; O = pollen; T = glandular trichome. (6) Plants have evolved apparently specialized structures to house ants: Y = yes; N = no. (7) Estimated number of congeneric ant species found regularly on the host genus; prob- ability of more (+) or several more (++) indicated parenthetically. Square brackets denote ants known to be unspecialized, or whose specialization is in doubt. (8) References for data on ants or plants: Bq = Bequaert 1922; W = Wheeler 1942; S&B = Schnell and Beaufort 1966; B = Benson 1985; H = Huxley 1986; J = Jolivet 1986; H&W = Holldobler and Wilson 1990; D = Davidson et al. 1989; IP = in press; PC = personal communication, DD and DM = respective author's observations. Volume 2, Number 1, 1993 69 oo c 06 r~ < Q. 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Z ^ ON 13 C 3 _ ca § 3 r3 a ^ CD "^ OX) -a ' E E a e 3 3 00 X -> '-> X S ii ON § "~ ca CD CT — 1 — I dj ^ Q ^ __ CD X X Ui 0 O — -C £2 t-4 ca X :0 X o — CO ca , — . E S x S-cq E 3 4^ O 1- 4-. O 3 ° o II U 3-i & £> ° -E '^x t3 e" O O CD U Jr ca •a ° « o a; -r o ■o 3 1> ■ ^r s" .s < OX) _o "o x "ca CD 'a. o OX) ca OX) 3 ca ex s CD CD CD O X 3 CD a 3 — O 13 CD rt CD ■3 CD 13 O J. HYM. RES. 2(1). 1993pp.85-96 Archaeoscoliinae, an Extinct Subfamily of Scoliid Wasps (Insecta: Vespida = Hymenoptera: Scoliidae) Alexandr P. Rasnitsyn Paleontological Institute, Russian Academy of Sciences, Moscow 117647 Russia Abstract. — Archaeoscoliinae. new subfamily, is established in the Scoliidae forthree new fossil genera and four new species: Archaeoscolia senilis, Cretoscolia promissiva, C. patiens, and Floriscolia relicta, from the Aptian (Early Cretaceous) of Mongolia, Cenomanian (Late Cretaceous) of Northeast Siberia, Turonian (Late Cretaceous) of Kazakhstan, and Oligocene (mid-Tertiary) of Colorado, respectively. INTRODUCTION The Scoliidae is a rather small family of aculeate wasps belonging to the superfamily Scolioidea (Rasnitsyn 1988) and embracing some 500 species (Brothers 1975). The fossil history of the family is little known. The only undisputable fossil represen- tative, Scolia prismatica Smith. 1855. from the Miocene of Shandong, China (attributed by Zhang ( 1989) to a living species), as well as two doubtful ones, Scolia? distincta Zhang (1989), found with the above species, and S. saussureana Heer ( 1 865), from the Upper Miocene of Oeningen, Germany, all belong to the Scoliinae, a cosmopolitan subfam- ily with greatest species diversity in warmer areas. The other subfamily, Proscoliinae, includes two species of a single relict genus, Proscolia Rasnitsyn (1977), from the eastern Mediterranean (Rasnitsyn 1977, Day et al. 1981. Osten 1987). The above fossils represent only a small section of scoliid history. The Paleontological Institute, Russian Academy of Sciences, Moscow (further abbreviated as PIN), and the American Museum of Natural History ( further referred to as AMNH ) both have additional fossil material that extend the mini- mal age of the family well into the Cretaceous, and shed light on the early stages of scoliid evolution. I would like to discuss two peripheral issues here. The first is my use the ordinal name Vespida in the title instead of the traditional Hymenoptera. My reasons are explained in full elsewhere (Rasnitsyn (1982, 1988, 1989. 1992). In summary they represent, first, appreciation of the general superiority of typified names (i.e., based on a ge- neric name) over descriptive ones in taxonomic nomenclature. This is a simple extention of prin- ciples in use for superfamily-family names for nearly 250 years. The second reason is the develop- ing awareness, at least among some Russian work- ers (e.g. Starobogatov 1991), that ordinal names should be based on established generic names. As to traditional names not based on generic ones, they seem useful and are used here in the form of vernacular names (e.g., hymenopterans, apocri tans, etc.). The second point concerns my approach to cla- distics. I appreciate the advantages of cladistic methods in the study of phylogeny, and I do my best to follow them in that kind of research. I deviate from traditional cladistic taxonomy in one impor- tant respect: I consider paraphyletic (ancestral ) taxa as fully legitimate (for details see Rasnitsyn 1987, 1988, 1992). This makes it possible to establish a new subfamily for the fossils in this paper, which represent a paraphyletic group. DESCRIPTIONS Archaeoscoliinae Rasnitsyn, new subfamily Diagnosis. — Fore wing (Fig. 1 ) with outer veinless zone narrow and not corrugated. Unlike Proscoliinae, cell r long, cell 3rm closed. Unlike Scoliinae, crossvein 2r-rs short, straight, crossveins r-m and 2m-cu always present. Hind wing (Figs. 3, 5) with RS and M very long before r-m, position of cu-a variable in respect to M-Cu fork. Head (Fig. 5) with clypeus short, adantennal tubercles weak, and, unlike Scoliinae, inner orbit only gently curved, oral cavity (Fig. 1 ) and, by implication, mouthparts 86 Journal of Hymenoptera Research short. Scutum with notauli (Fig. 1 , na) deep. Scutel- lum (Fig. 5, scl) elevated above metanotum (N3) instead of being leveled with it as in Scoliinae. Metanotum (Fig. 5, N3 ) short, clearly segregated in lateral depressions and central elevated area (metascutellum). Metasternal plate (Fig. 7, S3) small (though larger than largest in Tiphiidae), separating widely both mesosternal lobes and midcoxae but apparently not hindcoxae. Unlike Scoliinae, male hypopygium lacking 3 long spines exerting from abdominal apex, otherwise its pre- cise form unknown (Fig. 7). Unlike Proscoliinae, body size large (20-30 mm instead of 5.5-11.5 mm). Taxonomic position and relationships. — The fossils under description are assigned to the Scoliidae based on the following scoliid synapomorphies. In the fore wing (Fig. 1 ), the pterostigma is narrow, with crossvein r-rs extending from its apex, and cell 2rm is about as long as cell lmcu and produced basally to reach or even to surpass midlength of the upper side of lmcu. In the thorax, the propodeal dorsum is longitudinally tripartite (known for Archaeoscolia senilis, Fig. 1 ), and the metasternal plate is widely separating the mesosternal lobes (known for Floriscolia relicta, Fig. 7, S3). The venational characters are of particular im- portance, for unlike the other two characters listed above, they are present in all the fossils described here, including the incompletely preserved Cretoscoliapatiens (Fig. 5 ) which otherwise would hardly be identified as a member of the Scoliidae. On the other hand, unlike the structure of the propodeum and metasternal plate, the venational characters as described here are not uniquely de- rived. However, when taken in more detail, the character state of the cells 2rm and lmcu widely overlapping each other can be considered as uniquely derived. Indeed, the same character state is known in bees (Bombus spp., Xylocopa spp., etc.), velvet ants (Myrmosa spp.. Pseudophotopsis spp., etc.) and ants (many Ponerinae and Dolichoderinae). However, this overlapping is correlated in bees, ants, and velvet ants with, and probably achieved via, shortening of either lmcu (in ants) or, in bees and velvet ants, l+2r (the first submarginal cell). In contrast to these groups but similar to the living scoliids, the fossils under description retained both l+2r and lmcu cells long. Combined with the elongated basal half of the 2rm cell, this indicates that in both living and fossil Scoliidae the cells are widely overlapping due to direct elongation of the 2rm cell between the otherwise not modified l+2r and, lmcu cells. Within the family the fossils display several important autplesiomorphies: head with the adantennal tubercle small (known for Cretoscolia patiens, Fig. 5, at), thorax with the metasternum small (known for Floriscolia relicta Fig. 7, S3), and fore wing with the outer, veinless zone narrow and smooth, not corrugated ( also known for Floriscolia relicta. Fig. 7). The fossils lack synapomorphies that would permit assigning them to either of the two extant scoliid subfamilies. Archaeoscolia Rasnitsyn, new genus Diagnosis. — Apex of cell r just at crossvein 3r- m. Cell 3rm hardly elongate. Legs short, robust. Type species. — A. senilis, new species, from the later Early Cretaceous of Central Mongolia. Etymology. — The generic name is feminine, combined from the Greek adjective archaios mean- ing old, and the generic name Scolia. Archaeoscolia senilis Rasnitsyn, new species (Figs. 1,2) Description. — Sex not definitely known, but judging from general appearance is female. Body length minimum 20 mm, fore wing length up to end of cell 3rm 15 mm. Antenna not coiled, gradually becoming more narrow distally, with first segment preserved (true second or third) quadrate and last one twice as long as wide, flagellomeres subequal in length except last three longer. Fore wing with cell r obliquely truncate at junction with 3r-m. crossveins 2-3r-m both oblique, subparallel, 2r-m close to 2r-rs, cell 3rm rhomboid, cu-a scarcely postfurcal. Legs short, stout, hind tibia with long, stout spines on outer surface. No coarse surface structure discernible except reticulation on central propodeal area and short longitudinal ribs beyond reflexed anterior rib of second metasomal sternum. Ground color of body and appendages dark. Holotype — Unique specimen PIN #3359/4524 collected 5 to 8 km North of Bon Tsagaan Nuur Volume 2, Number 1, 1993 87 Figs. 1. Archaeoscolia senilis, new species, dorsal view. Scale line here and elsewhere 10 mm. Dotted lines represent structures seen through overlaying ones. Abbreviations: 2rm, lmcu. r, etc. = cells; 2r-rs, 3r-m, 1 m-cu, etc. = crossveins; no = notaulus; S2 = anterior rim of 2nd metasomal sternum. 88 Journal of Hymenoptera Research Figs. 2. Archaeoscolia senilis, new species. Lake, Bayanhongor Aymag (Region) in Central slender. Cell 3rm not elongate. Hind wing with cu- Mongolia, in upper Lower Cretaceous deposits a beyond M-Cu fork. probably of Aptian age. Type species. — C.promissiva, new species, from Etymology. — The species name is the Latin ad- the earlier Late Cretaceous of Northeast Siberia, jective senilis meaning old. Etymology. — The generic name is feminine, a combination of the island name Crete (from which Cretoscolia Rasnitsyn, new genus the scientific name of chalk and the Cretaceous period are also derived), and the generic name Diagnosis. — Unlike Archaescolia, cell r apex Scolia distant from 3r-m, and legs comparatively long and Volume 2, Number 1, 1993 89 Figs. 3. Cretoscolia promissiva, new species, ventral view. 90 Journal of Hymenoptera Research Figs. 4. Cretoscolia promissiva, new species. Volume 2, Number 1, 1993 91 Figs. 5. Cretoscolia patiens, new species. Abbreviations: at = adantennal tubercle; N3 = metanotum; mesoscutellum. scl Cretoscolia promissiva Rasnitsyn, new species (Figs. 3, 4) Description. — Female. Body size probably ca. 30 mm fore wing length up to apex of cell r 1 2 mm. Fore wing with apex of cell r distant of wing margin, scarcely surpassing apex of cell 3rm, 3rm shorter than high, crossvein 2r-m oblique, 3r-m strongly bent outward, much closer to 2r-m on M than on RS, cu-a scarcely postfurcal. Hind wing with curved incomplete supernumerary r-m crossvein (possibly individual aberration), cu-a far beyond M-Cu fork, Cu not bent at fork. Femora and tibiae narrow, hind tibia without evident spines on outer surface, hind tarsomere 5 thicker than hind tibia basally. Hind tibia with row of long, thick setae, hind tarsus covered with dense, thick, long setae, metasoma setose. Body and appendages prob- ably dark. Holotype. — Unique specimen PIN #3901/151 collected at Obeshchayushchiy Stream, right tribu- tary of Nil River upstream in Arman' River basin, Magadan Region in Northeast Siberia, in lower Upper Cretaceous (Cenomanian) deposits of Ola 92 Journal of Hymenoptera Research - % \ i I • »**„ -. j - -. ■ ..- i' Figs. 6. Cretoscolia patiens, new species. formation. minimally distant from wing margin and far ex- Etymology. — The species name is the feminine ceeding apex of cell 3rm, crossvein 3r-m probably form of the Latin adjective promissivus meaning oblique and not strongly bent. promising: this is the meaning ofthe Russian stream Description. — Sex unknown. Body size un- name Obeshchayushchiy, the type locality. known, fore wing length ca. 1 1 mm. Ocelli in low triangle, with hind ones ca. 1 .5 times closer to eye Cretoscolia patiens Rasnitsyn, new species than to each other and ca. 1.5 times closer to median Figures 5, 6 ocellus than to eye. Frons with strong elevated line running from mid ocellus to between antenna] Diagnosis.— Unlike type species, apex of cell r bases and wim sinuate impressions extending dor- Volume 2, Number 1 , 1993 93 sad from adantennal tubercles. Occipital carina complete or almost complete. Back surface of head with long longitudinal line apparently representing combined intergenal and interpostgenal sutures and indicating oral cavity as short (posterior cephalic structures are shown in dotted lines at Fig. 5). Fore wing with cell apex minimally distant from wing margi n and far exceeding apex of cell 3rm, crossvein 2r-m close to 2r-rs, 3r-m as preserved oblique, subparallel to 2r-m (possibly bent in its posterior quarter), cell 3r-m rhomboid, cu-a interstitial. Hind wing without supernumerary r-m, Cu apparently strongly bent at fork, meeting cu-ajust beyond fork. Leg moderately short, stout, probably with trochantellus delimited. Head dark, adantennal tu- bercles light, other fragments preserved (leg, metanotum, and obscure thoracic fragments) light except scutellum darker with light central area. No surface sculpture discernible. Holotype. — Unique specimen PIN #2783/260 collected at Kzyl-Zhar Hill in the north part of Karatau Range, Chiili District of Kzyl-Orda Re- gion in Kazakhstan, in lower Upper Cretaceous (Turonian) deposits. Etymology. — The name is the Latin adjective patiens, alluding to the poor state of the fossil. Floriscolia Rasnitsyn, new genus Diagnosis. — Fore wing with apex of cell r con- tiguous with wing margin, cell 3rm much longer than high. Unlike Cretoscolia hind wing with cu-a before M-Cu fork, and legs short, stout, even in male. Type species. — F. relicta, new species, from the Oligocene of western North America. Etymology. — The genus name is feminine, com- bining part of the name of the type species locality, Florissant, with the generic name Scolia. Floriscolia relicta Rasnitsyn, new species (Fig. 7) Description. — Male (judging from 13-seg- mented antenna). Body size 30 mm, fore wing length to apex of cell r 16 mm. Antenna with scape moderately short, pedicel short, ringlike. mid leg Fig. 7. Floriscolia relicta, new species, ventral view. Abbreviations: CX2, CX3 metasomal sternum; S3 = metasternal plate. mid and hind coxae; SI = ist 94 Journal of Hymenoptera Research flagellomeres becoming shorter and somewhat nar- rower apically, first almost three times as long as wide, penultimate one subquadrate. Fore wing with crossvein 2r-m arching, subvertical, 3r-m strongly bent, cell 3rm almost twice as long as high, much longer on M than on RS. Hind wing cu-a meeting M+Cu shortly before fork, joining A in smooth curve. Legs very short, outer midtibial surface apparently without spines. Metasoma somewhat constricted between first and second segments, second sternum with transverse impressed line subbasally. Metasomal apex conical, with no signs of trispinose hypopygium. No surface sculpture found except fine vertical striation of propodeal sides. Body parts and appendages dark. Holotype. — Unique specimen #28775 in AMNH collected at Florissant, Colorado, in deposits of Lower Oligocene (before mid-Tertiary). Etymology. — The species name is the feminine form of the Latin adjective relictus meaning rest, alluding to the relict nature of the insect, which existed much later than its relatives. ACKNOWLEDGMENTS My visit to the United States in 1989-1990 was supported by grants from the Museum of Comparative Zoology, Harvard University, Cambridge, MA (initi- ated by James M. Carpenter), The Smithsonian Institu- tion, Washington, DC. (initiated by Karl V. Krombein ), and The California Academy of Sciences, San Fran- cisco, CA (initiated by Wojciech J. Pulawski). My work at AMNH was made possible by David A. Grimaldi, who also gave me considerable help. An earlier version of the text was corrected both linguistically and in essence by efforts of the subject editor and two anonymous review- ers. I am particularly indebted to the subject editor for the crucial information concerning history of the terms parapsidal line, parapsis and notaulus. LITERATURE CITED Brodsky, A. K. 1991. Structure, functioning and evolu- tion of tergum in alate insects. I. Generalized scheme of structure. Entomologicheskoye Obozrenie 70: 297- 315 (in Russian, probably will be translated into English in Entomological Review). Brodsky, A. K. 1992. Structure, functioning and evolu- tion of tergum in alate insects. II. Peculiarities of organization of a wing-bearing tergal plate in insects of different orders. Entomologicheskoye Obozrenie 71: 39-59 (in Russian, probably will be translated into English in Entomological Review). Brothers, D.J. 1975. Phylogeny and classification of the Aculeate Hymenoptera, with special reference to Mutillidae. University of Kansas Science Bulletin 50: 483-648. Daly, H. V. 1964. Skeleto-muscular morphogenesis of the thorax and wings of the honey bee Apis millifera (Hymenoptera: Apidae). University of California Publications in Entomology 39: 1-77. Day, M. C. G. R. Else and D. Morgan. 1981 . The most primitive Scoliidae (Hymenoptera). Journal of Natu- ral History 15:671-684. Gibson, G. A. P. 1985. Some pro- and mesothoracic structures important for phylogenetic analysis of Hymenoptera, with a review of terms used for the structures. Canadian Entomologist 117: 1395-1443. Heer, O. 1865. Die Urwelt der Schweiz. Zurich, Fr. Schulthess. 622 pp. Matsuda, R. 1970. Morphology and evolution of the insect thorax. Memoirs of the Entomological Society of Canada 76: 431pp. Osten, T. 1987. Ein neuer Fundort von Proscolia spec- tator Day, 1981 (Hymenoptera, Aculeata). Entomo- fauna 8:361-365. Rasnitsyn, A. P. 1969. Origin and evolution of lower Hymenoptera. Transactions of the Paleontological Institute. Academy of Sciences of the U.S.S.R. 123. Nauka Press, Moscow. 196pp. (in Russian). Rasnitsyn, A. P. 1975. Hymenoptera Apocrita of Meso- zoic. Transactions of the Paleontological Institute, Academy of Sciences of the U.S.S.R. 147. Nauka Press, Moscow. 134 pp. (in Russian). Rasnitsyn, A. P. 1 977. A new subfamily of scoliid wasps (Hymenoptera). Zoologicheskiy Zhurnal 56: 522- 529 (in Russian with English summary). Rasnitsyn, A. P. 1980. Origin and evolution of Hy- menoptera. Transactions of the Paleontological In- stitute. Academy of Sciences of the U.S.S.R. 174. Nauka Press, Moscow. 192 pp. (in Russian). Rasnitsyn, A. P. 1982. Proposal to regulate the names of taxa above the family group. Z.N.(S.) 238 1 . Bulletin of Zoological Nomenclature 39: 200-207. Rasnitsyn, A. P. 1987. The importance of [not] being a cladist. Sphecos 14: 23-25. Rasnitsyn, A. P. 1988. An outline of evolution of the hymenopterous insects (order Vespida). Oriental Insects 22:115-145. Rasnitsyn, A. P. 1989. Vespida vs. Hymenoptera. Sphecos 1 8: 8. Volume 2, Number 1, 1993 95 Rasnitsyn, A. P. 1992. Principles of phylogenetics and taxonomy. Zkurnal Obshchey Biologii 53: 1 72- 1 85 (in Russian). Snodgrass, R. E. 1910. The thorax of the Hymenoptera. Proceedings of the United States National Museum 39: 37-91. Snodgrass, R. E. 1935. Principles of insect morphology. N.Y.: McGrowHill. 667 pp. Starobogatov, Ya. I. 1991. Problems in the nomencla- ture of higher taxonomic categories. Bulletin of Zoo- logical Nomenclature 48: 6-18. Tulloch, G.S.I 929. The proper use of the terms parapsides and parapsidal furrows. Psyche 36: 377-382. Zhang. Jun-feng.1989. Fossil insects from Shanwang. Shandong, China. Jinan: Shandong Science and Tech- nology Publishing House. 459 pp. (in Chinese, with English figure legends and descriptions of new gen- era). J. HYM. RES. 2(1), 1993 pp.97- 100 A New Species of Apocharips from Costa Rica (Hymenoptera: Cynipoidea, Charipidae) Arnold S. Menke Systematic Entomology Laboratory. Agricultural Research Service. USDA, c/o National Museum of Natural History. Washington D.C. 20560 Abstract. — Apocharips hansoni, new species, is described from Costa Rica. The wasp was reared from galls of Psyllidae. This is the first record of the genus Apocharips in the New World. Several unusual morphological features of the new species are discussed and illustrated. Paul Hanson of the Universidad de Costa Rica reared a few specimens of a charipid from galls of the psyllid genus Trioza Forster that were collected at high elevations in Costa Rica. Charipids reared from Psyllidae belong in the subfamily Charipinae. Menke and Evenhuis ( 1991 ) recognized five gen- era of Charipidae with the subfamily Charipinae being represented by Dilyta Forster and Apocharips Fergusson. Hanson's material belongs to the last genus and establishes that Apocharips occurs in the Western Hemisphere. The specimens represent a new species. Carver (1993) recognized a sixth charipid ge- nus, Thoreauana Girault, an Australian taxon that she removed from synonymy with Alloxysta, and assigned to Charipinae. Thoreauana has a small, basal tergum like Apocharips, but the antenna has 10-11 flagellomeres in the male and 9-10 in the female. All other genera of Charipidae have 12 male and 1 1 female flagellomeres. The genus Apocharips was described by Fergusson (1986) for a European wasp now known by the name trapezoidea (Hartig) (see Evenhuis. 1982). Menke and Evenhuis ( 1991 ) listed four Old World species in the genus, all reared from Psyllidae. The new species is assigned to Apocharips because it has a small tergum I (Fig. 9) and the veins of the marginal cell reach the wing margin. However, unlike other members of the genus, the apex of the scutellum has an apical boss (Figs. 2-6) rather than a clearly formed M-shaped carina. Thus, in Apocharips the condition of the scutellar apex varies. The presence of carinae at the apex of the scutel- lum was listed by Menke and Evenhuis ( 1 99 1 ) as an autapomorphy of the subfamily Charipinae, but it is now clear that this character has limited value. Carver (1992 (described and illustrated anew spe- cies, Alloxysta carinata (Alloxystinae), from Aus- tralia that has strong scutellar carinae apically. Thus at least one member of Alloxystinae has a character thought to be unique to Charipinae by Menke and Evenhuis. The new Costa Rican Apocharips described here further muddles the subfamily distinction since it only has a scutellar boss. The new species has most of the other attributes of the subfamily listed by Menke and Evenhuis (1991, table 1), some of which are depicted here: two mandibular teeth (Fig. 1 1 ), no frontoclypeal sulcus (Fig. 1 1 ), and pronotum with lateral carina (Fig. 1). I did not check conditonofthe spiracles on tergum VI because of the small number of speci- mens available, but assume that they are narrowly separated as in other species of the genus. The new species has another feature that is more intriguing than the condition of the scutellum. The face has converging ridges around the clypeus (Figs. 10-11). Such ridges appear to be unknown in any other member of the Charipidae, but are fairly common in the gall wasp family Cynipidae. This is evidently a parallelism. 98 Journal of Hymenoptera Research Figs. 1-6. Male thorax features of Apochahps hansoni, specimens from Volcan Poas. 1. left side of thorax. 2,3. posterolateral view of metanotum showing poorly defined apical boss (arrow). 4-6, left side, posterolateral, and rear views respectively, of metanotum showing more clearly defined apical boss (arrow). Volume 2, Number 1 , 1 993 99 Apocharips hansoni Menke, new species Black except as follows: scape and flagellomere I straw-colored; trochanters, apex of fore- and midfemora, foretibia, and foretarsomeres I-IV, straw-colored (midtibia and tarsus similar but darker). Face with numerous parallel ridges be- tween eye and mandible base (Figs. 10-11). Flagellomeres I-IV of female antenna without lin- ear tyli, but tyli present on V-XII; flagellomere II shorter than III, proportions of length of first three female flagellomeres: 6:3.5:4. Flagellomeres I-III of male antenna without tyli, but tyli present on remaining ones (Figs. 1-2); flagellomere I sinuate on outer side, longer than either II or III, propor- tions of flagellomeres I-III: 8:5.5:6. Apexofscutel- lum with a weak triangular boss that is not delimited by carinae (Figs. 2-3). or incompletely so (Figs. 4- 6). Metanotum with median longitudinal carina (Figs. 3, 6). Vein stub from marginal cell as long as flagellomere II. Female 1.7 mm long, males 1.5-2 mm long. Types. — Holotype female: Costa Rica, Cartago Prov., La Cangreja, 1950 m, March-May, 1992, Malaise trap operated by Paul Hanson (in National Museum of Natural History, Washington DC). Paratype males (four): one same data as holotype; two males, Alajuela Prov., Parque National Volcan Poas, 2500 m. May 26, 1 99 1 , ex Trioza sp. leaf gall on Phoebe or Nectandra (Lauraceae), collected by Paul Hanson; one male, same locality and host, Sept. 22, 1 99 1 , collected by Paul Hanson. Paratypes will be deposited in the Museo de Insectos, Universidad de Costa Rica, and the National Mu- seum of Natural History. Discussion. — Apocharips hansoni differs from the Old World species trapezoidea in a number of significant ways. A. hansoni has facial ridges that converge on the clypeus (Figs. 10-1 1 ), no tyli on the the first three male flagellomeres (Fig. 7), a feeble triangular boss on the scutellum (Figs. 2-6), and a carina on the metanotum (Figs. 3, 6); these features immediately separate hansoni from trapezoidea. I have examined a single female of trapezoidea (Hartig), and the figures in the well illustrated description of trapezoidea by Kierych (1979). A. trapezoidea lacks facial ridges, the male has tyli on all flagellomeres, the scutellum has an M-shaped carina apically, and the metanotum lacks a median carina. The head of hansoni in frontal view is more circular (Fig. 10) than that of trapezoidea. In the latter species the area below the eyes is more elongate and narrowed toward the mandibles. The spur on the marginal cell is longer in hansoni, particularly in the male. Distribution. — Known only from elevations between 1950-2500 m in Costa Rica. Etymology. — This tiny wasp is named after Paul Hanson who, by running many Malaise traps over a period of years, has probably sampled the micro-Hymenoptera fauna of Costa Rica more thor- oughly than anyone else. AC KNOWLEDGEMENTS The manuscript was reviewed by James Carpenter, American Museum of Natural History, New York; David Wahl, American Entomological Institute, Gainesville: and Alma Solis and David Nickle, Systematic Entomol- ogy Laboratory, USDA, Washington D.C. Their cri- tiques are much appreciated. LITERATURE CITED Carver, Mary, 1992. Alloxystinae (Hymenoptera: Cynipoidea: Charipidae) in Australia. Invertebrate Taxonomy 6:769-785. Carver, Mary. 1993. Australian Charipinae (Hy- menoptera: Cynipoidea: Charipidae ) described by A. A.Girault. Journal of the Australian Entomological Society 32:43-44. Evenhuis, H. H., 1982. A study of Hartig* s Xystus species with type designations and new synonyms (Hymenoptera: Cynipidae Alloxystinae and Charipinae). Spixiana 5:19-29. Fergusson, N. D. M., 1986. Charipidae, Ibaliidae & Figitidae. Hymenoptera: Cynipoidea. Handbooks for the Identification of British Insects 8 ( lc): 1-55. Kierych. E., 1979. Notes on the genera Dilyta Forster, 1 869. and Glyptoxysta Thomson, 1 877 ( Hymenoptera, Cynipoidea, Allosxystidae). Annates Zoologici 34:453-460. Menke, A. S. and H. H. Evenhuis, 1991. North Ameri- can Charipidae: key to genera,nomenclature, species checklists, and a new species of Dilyta Forster (Hy- menoptera: Cynipoidea). Proceedings of the Ento- mological Society of Washington 93 : 1 36- 158. 100 Journal of Hymenoptera Research Figs. 7-11. Male features of Apocharips hansoni. 7, dorsal view of scape, pedicel and flagellomeres 1-3 (and 4). 8, dorsal view of flagellomeres 4-6 enlarged from right antenna shown in fig. 7. 9, left side of abdomen. 10. 11. view of face, arrow points to facial ridges. J. HYM. RES. 2(1), 1993 pp.101-105 New Neurotoxins From Venoms Of Aculeate Hymenoptera: A Contribution To The Knowledge Of Stinging Behaviour Tom Piek Department of Pharmacology, University of Amsterdam. Meibergdreef 15. 1 105 AZ Amsterdam. The Netherlands Abstract - Several Hymenoptera produce a venom which contains a neurotoxic component. Kinins, present in venoms of vespid, scoliid, tiphiid, multillid and formicid Hymenoptera, irreversibly block the transmission in the insect CNS presynaptically by depletion. Poneratoxin, a neurotoxic compound isolated from ant venom, affects the ion current in voltage-dependent channels in nerve and muscle fibres. Philanthotoxins block the neuromuscular transmission and the synaptic transmission in the CNS of insects. The results support the idea that entomophagous Aculeata sting their prey in the CNS and explain the effects of the sting on insects and mammals. INTRODUCTION Within the phylum Arthropoda several groups include well known producers of venoms: the spi- ders, the scorpions and the hymenopteran insects. In the first seventy years of this century a number of arthropod venoms has been described. A manual of information was presented in a volume on Arthro- pod Venoms edited by Sergio Bettini ( 1978). The biochemical, pharmacological and behavioural as- pects of venoms produced by Hymenoptera were collected together by Piek (1986). Although the latter book provides the reader with extensive docu- mentation of observations and research during the last 100 years on bee. wasp and ant venoms, several of the most interesting wasp and ant neurotoxins which have a relation to the stinging behaviour of these insects were not yet chemically characterized in the first half of the 1980's. It is the aim of this paper to review the several types of neurotoxic effects of solitary wasps and thus contribute to the understanding of stinging behaviour. HYMENOPTERA AS NEUROTOXIN PRODUCERS The earliest report of a neurotoxic effect on an insect by a solitary wasp may be in the Erh-ya yin t'u or Dictionary of Old Terms, of which the Sung illustrations may originate between 500 and 400 BC (Bodenheimer 1928). The idea, that "in seven days the worm stung by the wasp was transformed into the son of the wasp," conveys the notion that the prey was not killed but was otherwise incapaci- tated. A principal question during the eighteenth and nineteenth centuries was whether prey of solitary aculeate wasps were killed or paralysed. Advocates of the killing idea were Reaumur ( 1 742 ) and Dufour (1841). Sympathizers with the idea that prey of solitary wasps were not killed but paralysed were, for example, Bartram (1744, 1749) and Audouin (1839). It fell to Fabre (1855) to settle the conflict of views by electrically stimulating weevils, stung to a complete and irreversible immobility by the sphecid wasp Cerceris tuberculata (Villers) thus demonstrating that the prey was capable of move- ment and therefore in deep paralysis, not dead. Solitary wasp venoms cause paralysis by neuro- toxic action and we now know that neurotoxic principles are also found in bee venoms, social wasp venoms and ant venoms. KININS FROM VESPID AND SCOLIID WASP VENOMS Kinins are neurotoxic components of wasp and ant venoms, causing in the insect central nervous system a presynaptic block of the cholinergic trans- mission by means of an irreversible depletion of transmitter substance (acetylcholine), probably by means of a non-competitive inhibition of the pre- synaptic choline-uptake (Piek et al. 1987, 1990; Piek 1991). 102 Journal of Hymenoptera Research Wasp kinins are polypeptides of 9-18 amino- acid residues containing a bradykinin-like sequence as part of the molecule. The bradykinin-like se- quence is either identical to the vertebrate bradyki- nin, or differs in a single OH-group (prolin be- comes hydroxyprolin, Hyp'-bradykinin) or differs in a single CH3-group (Thrh-bradykinin). A brady- kinin-like substance was discovered as a venom constituent of the wasp Paravespula vulgaris (L.) (Jacques and Schachter, 1 954) and was called wasp kinin (Schachter and Tain 1954). Although the chemical characterization of this wasp kinin is still unknown, other social wasp kinins have been char- acterized chemically (for reviews see Nakajima 1986 and Piek 1991). Despite the fact that wasp kinins have been known for more than 35 years, their neurotoxic actions had not been discovered before the demon- stration of the presence of kinins in the venom of the solitary waspMegascoliaflavifrons (F.) (Piek et al. 1983, 1984b, Yasuhara et al. 1987). A point of interest is that this wasp stings larvae of the Euro- pean rhinoceros beetle Oryctes nasicornis L. pro- ducing an irreversible paralysis, by successively penetrating the ventral side of all segments, which contain nerve ganglia ( Piek et al. 1 983 ). This scoliid wasp probably injects its venom into the nerve ganglia, a phenomenon which has commonly been observed for many solitary aculeate wasps (see also section on philanthotoxins). The idea that these wasps sting into the nerve ganglia prompted study of the effect of the venom and its fractions, and of purified or synthesized toxins, by means of microperfusion of an insect ganglion. This became the start of a series of experiments on the neurotoxic action of threonine-6-bradykinin (ThiJ,BK ), the most active kinin in the venom of M.flavifrons (Yasuhara et al. 1 987) and of Colpo interrupta (F.) (Piek et al. 1990). When a venom solution, prepared of isolated venom reservoirs of M.flavifrons was injected into the haemolymph of an Oryctes nasicornis larva, or when a female M.flavifrons was forced to sting the larva, no paralysis occured ( Piek et al. 1 983). How- ever, the venom preparation was very active, as a blocker of synaptic transmission, when injected ( by microperfusion) into the sixth abdominal ganglion of the cockroach, Periplaneta americana L. (Piek et al. 1987). It was shown that Thr6BK irreversibly blocks synaptic transmission from the cereal nerve XI of the cockroach to a giant interneuron in the sixth abdominal ganglion (Hue and Piek 1988. 1989). The presence of kinins as producers of neuro- toxic insecticidal effects in the venoms of Vespidae, Scoliidae, Tiphiidae, Mutillidae and Formicidae might be resolved as a toxinological argument for the phylogenetic relationship of these groups (Piek 1991, 1992). However, part of this view is in conflict with other evidence (Brothers 1975). PONERATOXIN, A NEUROTOXIC ANT VENOM COMPONENT Compared to the information available for bee and wasp venoms, knowledge about neurotoxic ant venoms is limited. Nevertheless, ant venoms have provided new tools for the study of neurophysiol- ogy, such as piperidine alkaloids in fire ant venoms (review: Schmidt 1 986) and poneratoxin (Piek et al. 1991 a,b). Following en venomation of man by the ponerine ant Paraponera clavata (F.), Schmidt et al. (1984) reported uncontrollable trembling which was not caused by pain alone. The venom contains at least two fractions which block specifically neuronal signals in the insect central nervous system (CNS) ( Piek et al. 1 99 1 a). One of the fractions of the crude venom was pharmacologically characterized as a kinin. Although the chemical structure of this ant kinin is still unknown, its pharmacological action is comparable to the wasp kinins described in the preceding section. The second neurotoxic fraction proved to be the most potent blocker of CNS functions. It contained a very potent neurotoxic peptide of 25 amino acid residues, called poneratoxin (Piek et al. 1991a). This has been synthesized by Professor Terumi Nakajima (Tokyo). At concentrations varying from 108 to 10-6M the synthetic poneratoxin (PoTX) blocks synaptic transmission in the insect CNS in a concentration-dependent way and it depolarizes giant interneurons. At comparable concentrations PoTX affects the electrical activity of isolated cock- roach axons, as well as of isolated frog and rat skeletal muscle fibres. The explanation of these Volume 2, Number 1, 1993 103 actions is the finding that PoTX prolongs action potentials and thus induces slow automatic activity. This is a consequence of a slow sodium ion-current activation at unusual negative values of potential and due to slow deactivation (Piek et al. 1991b Duval etal. 1991, 1992). This explains the insecti- cidal action of a sting of the ant into an insect prey, and also the fibrillation of skeletal muscles of man (Schmidt etal. 1980)andinsects(Pieketal. 1991b). As a venom reservoir of a single ant specimen {P. clavata) may contain about 1 ug poneratoxin (Piek et al. 1991a), injection of its content may result, for small insects, in a final concentration of between 1 0 5 and 1 0 4M. Even a tenth of the venom reservoir content injected into the CNS immedi- ately and irreversibly blocks neuronal functions. For vertebrates about 30 stings of Paraponera clavata per kg can be lethal (LD5(): 33 stings/kg; Schmidt et al. 1980). If this results in about 30 ug of poneratoxin per kg, the final concentration of poneratoxin will be in the order of 10'8T0~7M, a level which is probably lethal. The uncontrollable trembling and unbearable pain caused by a sting by P. clavata is explained by the hyperactivity of the nervous network caused by prolongation of action potentials. It is concluded that poneratoxin alone could explain the reversible neurotoxicity of the venom of P. clavata, but the kinin present in the venom, may contribute to the insecticidal action consider- ably by blocking irreversibly the synaptic neu- rotransmission. PARALYSIS OF PREY BY PHILANTHOTOXINS The two first examples of neurotoxins (kinins and poneratoxin) are polypeptides produced by vespoid Hymenoptera. Our knowledge of venoms of those wasps which belong to a quite different group, the Apoidea spheciformes (or sphecid wasps ) is relatively poor. The venom and its constituent neurotoxins has been well described for only a single species, i.e. that of the sphecid wasp Philanthus triangulum {¥.). The venom contains at least two different toxins that are antagonists for the glutamatergic neuromuscular transmission in in- sects (Piek and Spanjer 1986). The two toxins are chemically characterized as B-philanthotoxin (-B- PTX) and -philanthotoxin (PTX-4.3.3) respec- tively (Karst et al. 1990, 1991, Karst and Piek, 1991). These philanthotoxins are polyamine-like structures that block both the insect neuromuscular transmission and the nicotinic synaptic transmis- sion in the insect central nervous system (Hue and Piek 1989, Karst et al. 1990. 1991, Karst and Piek 1991). STINGING BEHAVIOUR In his Souvenirs Entomologiques Fabre ( 1879- 1910) presented the view that solitary wasps sting their victims in the CNS. He observed prey having a concentrated CNS (buprestid beetles, weevils and some beetle larvae) to be stung once and observed that prey with a more diffuse CNS were stung more than once. Among his examples were Sphex spp. which sting crickets three times, once in each of the three main nerve ganglia, and Ammophila spp. which sting caterpillars in every segment contain- ing a major nerve ganglion. Based on observations over more than twenty years, Steiner (1986) tested in sphecid wasps six different hypotheses concerning sting number, lo- cation of sting, sting direction and other character- istics. Conceivably, the number, location and direc- tion of successive stings could have been affected by (1) soft spots in the integument of the prey (Ferton's soft spots hypothesis; Steiner 1986), (2) body segmentation, (3) leg bases, (4) complete set of ganglia or (5) ganglia involved in locomotion and defence. The null hypothesis would be random stinging. Steiner (1986) concluded that although a wide spectrum of stinging methods could not easily be encapsulated in a single simple formula, the locomotor ganglia hypothesis of stinging is the best-fitting one for a number of aculeate wasps which prey on large or powerful insects. These wasps give at least one different sting for each clearly separate nerve centre involved in locomo- tion, attack, defence or resistance of the prey. In a single case the localization in a cross section of the mesothorax of Mitsca domestica L. of radio- actively labelled venom of the sphecid wasp Mellinus an'ensis L. has been demonstrated (Piek 1978, see also Steiner 1986). The extensive docu- mentation on stinging behaviour in relation to the 104 Journal of Hymenoptera Research effects of stinging on prey (Steiner 1986, Piek and Spanjer 1986) suggests a general rule: entomopha- gous Aculeata sting into the CNS of the prey. The blocking action in the insect CNS of the venoms of Phi Ian thus triangulum (Hue and Piek 1989) and of Megascolia flavifrons (Piek et al. 1987) also sup- ports Steiner' s conclusion. Several unpublished pilot studies in our labora- tories indicate that the venoms of sphecid wasps other than P. triangulum did not affect the insect neuromuscular transmission. We may speculate that the ability of/3, triangulum to paralyse its prey (workers of the honeybee) by a peripheral effect on muscle contraction has been developed because of the dangerous defensive behaviour of the prey. When, for example, a female P. triangulum is brought together with ten honeybee workers, the wasp is sometimes killed by one of the last bees to be attacked. Therefore, it may be safer for the wasp to give a random sting, which quickly but revers- ibly incapacitates the bee. Subsequently a sting is given into the thoracic ganglion complex and the process is often completed by a sting into the suboesophageal ganglion. This complete stinging sequence results in a long-term paralysis. A different, but to a certain degree comparable stinging behaviour has been described for Ampulex compressa F. and Liris nigra F. A sting in the thorax of the cockroach transiently paralyses the victim. During that short-lived immobility of the cock- roach, the wasp stings carefully into the suboesophageal ganglion. Only this latter sting results in a delayed and irreversible change of behaviour of the cockroach (Steiner, 1986, Piek et al., 1984, 1989). It might be clear that the explanation of the atypical venom composition of P. triangulum has to be supported by studies of venoms of other bee- hunting or wasp-hunting sphecid wasps. It may be a challenge to students of the biology of the solitary wasps to collect arguments in favour or against the above mentioned view. LITERATURE CITED Audouin, V. 1839. Deuxieme lettre pour servir de materiaux a 1'histoire des insectes contenant des observations sur les moers des Odyneres.A/»irt/e.v des Sciences Naturelles 2: 1 04- 113. Bartram, J. 1744. An account of some curious wasps nests made of clay in Pensilvania. Philosophical Transactions of the Royal Society of London 43:363- 365. Batram, J. 1749. A description of the great black wasp from Pensilvania. Philosophical Transactions of the Royal Society of London 46:278-279. Bettini, S. 1978. Arthropod Venoms. Springer Verlag. Bodenheimer, F. S. 1928. Materialen zurGeschichte der Entomologie his Linne, Vol. I. II. W. Junk, Berlin. Brothers. D. J. 1975. Phylogeny and classification of the aculeate Hymenoptera. The University of Kansas Science Bulletin 50:483-648. Dufour, L. 1841. Observations sur les metamorphoses du Cerceris bupresticida et sur l'industrie et 1" instinct entomologique de cet Hymenoptere. Annates des Sciences Naturelles 2:353-370. Duval, A.. C. O. Malecot, M. Pelhate and T. Piek. 1991 Poneratoxin converts fast voltage-dependent sodium channels into slow operating ones at negative poten- tials. Pesticide Science 32:374-375. Duval, A., C. O. Malecot, M. Pelhate and T. Piek. 1992. Poneratoxin, a new toxin from an ant venom, reveals an intercon version between two gating modes of the Na Channels in frog skeletal muscle fibres. Pfliigers Archiv 420:239-247. Fabre, J. H. 1 855. Observations sur les moers de Cerceris et sur la cause de la long conservation des coleopteres dont ils approvisionment leurs larves. Amies de Sciencias Naturaes 4: 129-150. Fabre, J. H. 1879-1910. Souvenirs Entomologiques. Delagrave, Paris. Hue. B. and T. Piek. 1988. Effects of kinins and related peptides on synaptic transmission in the insect CNS, In G. G. Lunt, ed., Neurotox'88. International Con- gress Series 832:27-33. Jaques. R. and M. Schachter. 1954. The presence of histamine, 5-hydroxytryptamine and a potent slow- contracting substance in wasp venom. British Jour- nal of Pharmacology 99:53-57. Karst, H. and T. Piek. 1991. Structure-activity relation- ship of philanthotoxins-II. Effect of the glutamatergic gated ion channels of the locust-muscle fibre mem- brane. Comparative Biochemistry and Physiology 98C:479-489. Volume 2, Number 1, 1993 105 Karst, H.. R. H. Fokkens, N. de Haan, G. Heuver. B. Hue. C. Kruk, N. M. M. Nibbering,T. Piek, W. Spanjer, Y. C. Tong and W. van der Vliet. 1990. Beta- philanthotoxin, a novel glutamatergic antagonist for insect neuromuscular transmission. Comparative Bio- chemistry and Physiology 97C:3 1 7-327. Karst, H., T. Piek, J. van Marie, A. Lind and J. van Weeren- Kramer. 1991. Structure-activity relation- ship of philanthotoxins-I. Pre- and postsynaptic inhi- bition of the locust neuromuscular transmission. Comparative Biochemistry and Physiology 98C :47 1 - 477. Nakajima, T. 1986. Pharmacological biochemistry of vespid venoms. In: T. Piek, ed.. Venoms of Hy- menoptera, pp. 309-327. Academic Press, London. Piek, T. 1978. Wespegif als natuurlijk insecticide. Natuur enTechniek46:l5S-l73. Piek. T. 1986. Venoms of Hymenoptera: Biochemical, Pharmacological and Behavioural Aspects. Aca- demic Press, London. Piek, T. 1991. Neurotoxic kinins from wasp and ant venoms. Toxicon 29:139-149. Piek, T. 1992. A toxinological argument in favour of the close relationship of Vespidae. Scoliidae. Tiphiidae, Mutillidae and Formicidaet Hymenoptera). Proceed- ings of Experimental and Applied Entomology 3:99- 104. Piek, T. and W. Spanjer. 1986. Chemistry and pharma- cology of solitary wasp venoms. In: T. Piek, ed.. Venoms of Hymenoptera, pp. 161-307. Acadmic Press, London. Piek, T., A. Buitenhuis, R. T. Simonthomas, J. G. R. Ufkes and P. Mantel. 1 983. Smooth muscle contract- ing compounds in the venom of Megascoliaflavifrons (Hym. -Scoliidae) with notes on the stinging behaviour. Comparative Biochemistry and Physiol- ogy 75C:145-152. Piek, T„ J. H. Visser and R. L. Veenendaal. 1984a. Change in behaviour of the cockroach. Periplaneta americana, after being stung by the wasp Ampulex compressa. Entomologia Experimentalis etApplicata 35:192-203. Piek, T., P. Mantel and C. J. W. van Ginkel. 1984b. Megascoliakinin, a bradykinin-like compound in the venom of Megascoliaflavifrons ( Fab. ) ( Hymenoptera: Scolidae). Comparative Biochemistry and Physiol- ogy 78C473-474. Piek, T., B. Hue. L. Mony. T. Nakajima, M. Pelhate and T. Yasuhara. 1987. Block of synaptic transmission in insect CNS by toxins from venom of the wasp Megascoliaflavifrons ( Fab. ). Comparative Biochem- istry and Physiology 87C287-295. Piek, T., B. Hue. A. Lind, P. Mantel. J. Van Marie and J. H. Visser. 1989. The venom of Ampulex compressa - effects on behaviour and synaptic transmission of cockroaches. Comparative Biochemistry and Physi- ology 92C: 175-183. Piek, T., B. Hue, P. Mantel, T. Nakajima, M. Pelhate and T. Yasuhara. 1990. Threonine6-bradykinin in the venom of the wasp Colpa interrupta (F.) presynapti- cally blocks nicotinic synaptic transmission in the insect CNS. Comparative Biochemistry and Physiol- ogy 96C: 157-162. Piek, T.. A. Duval. B. Hue, H. Karst, B. Lapied, P. Mantel, T. Nakajima, M. Pelhate and J. O. Schmidt. Poneratoxin, a novel peptide neurotoxin from the venom of the ant, Paraponera clavata. Comparative Biochemistry and Physiology 99C:487-495. Reaumur(Ferchauld, R. A. ). 1 742. Memoires pour servir a I'histoire des insectes, T. VI. Imprimerie Royale, Paris. Schachter, M. and E. M. Thain. 1954. Chemical and pharmacological properties of the potent slow con- tracting substance (kinin) in wasp venom. British Journal of Pharmacology 9:353-359. Schmidt, J. O. 1986. Chemistry, pharmacology and chemical ecology of ant venoms. In: T. Piek, ed., Venoms of the Hymenoptera, pp. 425-508. Academic Press, London. Schmidt, J. O., M. S. Blum and W. L. Overal. 1984. Hemolytic activities of stinging insect venoms. Ar- chives for Insect Biochemistry and Physiology 1 : 155- 160. Steiner, A. 1986. Stinging behaviour of solitary wasps. In:T. Piek.ed., Venoms of Hymenoptera, pp. 63-160. Academic Press, London. Yasuhara, T., P. Mantel, T. Nakajima and T. Piek. 1 987. Two kinins isolated from an extract of the venom reservoirsof the solitary wasp Megascoliaflavifrons. Toxicon 25:527-535. J. HYM. RES. 2(1), 1993 pp.107-1 16 Syntomopus Walker: The Nearctic Species with a Review of Known Host Associations (Hymenoptera: Pteromalidae) Steven L. Heydon Boliart Museum. Department of Entomology, University of California, Davis. California 95616 Abstract. - Syntomopus Walker is a cosmopolitan genus of 1 3 described species. Syntomopus is defined, its relations to other pteromalid genera are discussed and a host list is presented for the species. Known hosts include mostly stem-mining Agromyzidae. but stem-mining Lepidoptera. and possibly Cynipidae are also hosts. The species of the United States and Canada are reviewed. Syntomopus affinis Ashmead, 1 896 is synony mized with 5. americanus Ashmead. 1894 and a new Nearctic species, S. arpedes, n. sp., is described. Syntomopus Walker contains 1 3 described spe- cies: 5. shakespearei (Girault), 1913 from the Aus- tralian region; S. agromyzae Hedqvist, 1972, 5. incisus Thomson, 1878,5. incurvus Walker, 1833, S. oviceps Thomson, 1878, S. pallipes Rudow, 1886, and S. thoracicus Walker, 1833 from the Palearctic region; 5. fuscipes Huang, 1991 from the Oriental region; S. gracilis De Santis, 1976 (in De Santis et al., 1976), S. incidoideus Howard, 1896. and S. parsii De Santis, 1976 from the Neotropical region; and S. affinis Ashmead. 1896 and S. americanus Ashmead, 1 894 from the Nearctic re- gion. In this paper, I synonymize S. affinis with S. americanus and describe a new Nearctic species, S. arpedes, n. sp. Terminology in this paper follows that of Gra- ham (1969), except that genal concavity is used instead of genal hollow and club is used instead of clava. In addition, the gastral terga are numbered TI-T7 beginning with the first tergite after the petiole. The following abbreviations are used; the median ocellar diameter is MOD, the ocellar-ocu- lar distance is OOL. the posterior ocellar distance is POL, the lateral ocellar distance is LOL, the multiporous plate sensilla are MPP sensilla, the lowerocularline is LOcL, and the antennal funicular segments are Fl through F6. The units of measure- ment given in the descriptions can be converted to millimeters by multiplying by 0.02. The acronyms for the museums from which specimens were ex- amined are given in the Acknowledgments. Genus Syntomopus Walker Syntomopus Walker, 1833:371, 372. (Type spe- cies: Syntomopus thoracicus Walker, 1 833; sub. desig. by Westwood, 1839:69; examined). Forster. 1856:52, 56. Thomson, 1878:17, 23. Ashmead, 1904:330, 331. Schmiedeknecht, 1909:374, 375, 376-377. Nikol'skaya, 1963:247-248. Peck, Boucek, and Hoffer, 1 964:40. Graham, 1 969: 1 24, 1 37- 1 40. Hedqvist, 1972:210-215. Dzhanokmen, 1978:76, 79-80. Burks, 1979:787. Boucek. 1988:238,466. Merismorella Girault, 1926:1. (Type species: Merismorella shakespearei Girault; monotypy: not seen). Boucek, 1988: 466 (synonymy). Description. — Head, mesosoma, coxae, peti- ole, gaster metallic dark blue or green; scape metal- lic or nonmetallic. Head with clypeus having three broad symmetrically arranged clypeal denticles (Fig. 1 ); lateral part of mouth margin with short genal concavity; antennal torulus distinctly above LOcL. Antenna with scape cylindrical, 5X as long as wide; flagellum compact, with segments cylin- drical and typically transverse in females (quadrate in S. agromyzae); MPP sensilla in single row; club of female without large patch of micropilosity, tip lacking spine. Maxilla of male with palp slender, stipites unenlarged. Mesosoma flattened dorsally (Fig. 2) except in S. agromyzae; pronotal collar long, length 1/4-1/3 its width, dorsal level of collar below that of vertex, humeral angles squared, ante- rior edge rounded; notaulus shallow; scutellum 108 Journal of Hymenoptera Research typically about as long as wide (longer than wide in S. agromyzae), lacking anterior median groove, with two pairs of lateral setae, frenal area nearly indistinguishable from remainder of scutellum; dorsellum crescent-shaped; propodeum with me- dian panels long (width about 1 .5X length), median carina (except in S. incisus) and plicae well devel- oped and connected posteriorly by W-shaped ca- rina. Fore wing with relative lengths of veins as follows: submarginal > marginal > postmarginal > stigmal; costal cell with at least one complete row of setae; basal cell bare; basal vein setose or bare; speculum developed, open posteriorly. Petiole longer than wide, cylindrical; with complete basal flange continuous laterally and ventrally; without median carina; lateral setae present. Gaster of fe- male ovate acuminate; hypopygium extending to near tip of T7; in both sexes hind margin of Tl sinuous laterally, typically emarginate medially (entire in S. oviceps). Discussion. — Finding a suite of character states to define Syntomopus is complicated by intermedi- ate forms between it and Thinodytes Graham, Maidens Graham, and Ploskana Boucek. The most distinctive characteristic of most Syntomopus spe- cies is the flattened mesosoma (Fig. 2), but this character state is of limited value for defining the genus. Flattened thoraces, similar to those of most Syntomopus species, occur throughout the Pteromalidae in many genera including Ploskana, Ksenoplata Boucek, and Anogmus Forster. Some Syntomopus species, such as S. agromyzae and some undescribed Neotropical species, have a nor- mally arched mesosoma. As noted by Boucek (1988), the pronotal collar of Syntomopus is large, being 1/4 to 1/3 as long as wide and rectangular in dorsal view (Fig. 2). The pronotum of Ploskana is similarly lengthened, but it is distinctly narrowing anteriorly (see fig. 3, Boucek 1976). Besides hav- ing the character states defining the Halticoptera- group [those miscogasterine genera characterized by areticulately sculptured body, acarinate pronotal collar, weakly developed notauli, weakly delimited frenum, propodeum with sharp median carina and plicae connected posteriorly by W-shaped carina, petiole with a basal bracing consisting of an anteri- orly directed lateral and ventral flange, and the hind margin of the first gastral tergum being sinuous laterally and usually emarginate medially; Heydon 1988], Syntomopus can be defined relative to other related genera by possession of the following two autapomorphies: 1-three symmetrically arranged clypeal denticles ( Fig. 1 ) and 2-an enlarged pronotal collar with squared humeral angles (Fig. 2). Genera of related groups such as the Cyrtogaster-group ( Heydon 1 989) and Nodisoplata Graham also have three symmetrically arranged clypeal denticles, but this symmetrical arrangement of clypeal denticles is unique for Syntomopus within the Halticoptera- group. Graham ( 1969) placed Syntomopus as the clos- est relative of Sphegigaster Spinola. This relation was echoed by Boucek ( 1976) in his description of Ploskana, which he described as having similari- ties to both of the former two genera. However, a close relationship between Syntomopus and Sphegigaster is unlikely since there are no synapomorphies supporting such a relationship between them. Character states they share in com- mon are either plesiomorphic, such as the rounded anterior edge of the pronotal collar, or synapomorphiesbothSphegigasterandSyntomopus also share with the other genera of the Halticoptera- group, such as the shallow notauli, short postmarginal vein, obliterated frenal sulcus, long reticulate petiole, and sinuous lateral margin of T 1 . Sphegigaster lacks character states that define the Halticoptera-group such as the W-shaped carina connecting the median carina and plicae, and the median emargination of the first gastral tergum. In Sphegigaster, species lack all traces of propodeal carinae, and the hind margin of T 1 is entire mesally . Biology. — Syntomopus is exceptional among the Pteromalidae because hosts are known for many of the described species (Table 1 ). Syntomopus species are parasitoids, emerging from the pupal stadium of insects boring the stems of plants — commonly Asteraceae. Their hosts are mostly Diptera, but S. arpedes, S. americanus, and S. incurvus have been reared from lepidopteran stem borers, and S. incisus has been reared from a cynipid gall. From the illustration, it is clear that the two pteromalid parasitoids identified as Syntomopus Volume 2, Number 1, 1993 109 c o co ■~ o CD L. ■*- to o X c 0. CM ■^• r- o~> oo t— T to £ > a; X C/3 CD 5 "co CO 01 O CO S y _j To co CO co S CD >; CO 5 -i "C CD ° ~ ■+~* O « s .CO CO "^; fc co CD CO Q. O co co c CO '5 -Q < CO o en CD £5 CO CO X X CO o 3 CO P a, CD ro ~3 CL CO 2 o CL ^ CO X CD CO CD CO T3 CO CO "D X! .^ 3 CO N "n a CO >^ >, '3 ■o O E E CD 3 CO CO O CD o CO N o CO < CO 1_ o i_ . CO Q.< CO . . co ro £® E .9- 8 9 .3 O CO CO N CO i_ O '3 cd .3 '5 X I £ E 5 a> Q. u a) o b o X CO CO CO cd """" D) CD i to _c I «* 3: o. 3 a o o CD 3 3 CO .o 3 1w en CD CO CO o E »^ CD p CD o Q. 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D) CD < -o „ CO CO ^ CD E .9- ■9 Q .3 - — - 3 CD CD CJ) CO CD co -Q O O .CtJ .O '& O CO CD CD C "■ CD CO CO CD O co E £ to ■S c CD c CD CO CO I 9 3> co c -2 CD CO < CD CD CD CD CO co O) .c .c c CO co CO 1— 3 o CD X CD O c CD Q. CO '3 9 co CD CO 9r CD 3. CO CD CO O O CD 5 o 'co 3 CO 3. CO -c CO 5 o CO CO CO CO 3 3 3 3 3. 3 a 3 O O o O E E s E p o o o -*— -i— •*— *— 3 3 c c >* ^ X is CO CO CO CO CD 0 N CD .03 CO 00 co en oo CD CD E co CD CO CD O CO O) CO CZ CO CD XI c o 0) c CD N CD CO o~ CO 3) CO c -2 D. Q. CO s E 9 I a> c 'CO 1— > CO X CO -^ CO 0 55 CO 3 9 3 E 3 Volume 2, Number 1, 1993 111 species in Bruzon, Martinez, and Calderon (1968) are not Syntomopus. Syntomopus arpedes Heydon. new species Figs. 2, 3 Holotype, female. — Color: Anterior of head, dorsum of mesosoma dark green, face and scutel- lum more blue; occiput, neck, pleural regions, coxae, petiole dark blue; gaster dark brown with metallic reflections on Tl . Antenna with scape and pedicel yellow-brown with strong metallic green reflections; remainder brown. Legs with trochant- ers and femora brown with strong green reflections; tibiae yellowish brown mesally, paler at tips; fore tarsus yellow-brown; middle and hind tarsi white. Wing veins pale yellow-brown, parastigma more reddish brown. Sculpture. — Clypeus smooth with fine striae laterally; frenum coriaceous; dorsellum smooth; Tl-6 smooth; T7 coriaceous. Structure. — Body length 2.3 mm. Head ovate in anterior view; width 1 .2X height (36.5:3 1 .0), 2.8X length (36.5: 1 3.0) (Fig. 3); front of head flat, scrobes absent; lateral teeth of clypeus very weak; genal concavity extending 1/3 malar distance; eye height 2. IX length (19:9), 2.4X malar distance (19:8), length 3.0X temple length (9:3); ratio of MOD, OOL, POL, LOL as 3:6:9:4; torulus IX own diam- eter above LOcL. Antenna with length of pedicel plus flagellum 0.79X head width (29.0:36.5); ratio of lengths of scape, pedicel, annelli, Fl-6, club as 11.0:4.0:1.0:3.0:2.5:2.5:2.5:2.5:2.5:8.0; widths of F 1 , F6, club as 3 :4:4; club with patch of micropilosity ventrally on terminal segment. Mesosoma flat- tened dorsally (Fig. 2). length 1.9X width (60.0:31.5), width 2. IX height (31.5:15.0); pronotum with sides weakly convergent anteriorly, humeral angles squared, length 0.35X width (9.5:27.0); propodeum in same plane as rest of mesosoma, median carina complete but weakly developed, plicae sharp but fading out just at ante- rior margin of propodeum, nucha acarinate anteri- orly. Fore wing length 2.2X width (85:39); ratio of lengths of submarginal, marginal, postmarginal, stigmal veins as 37:20: 13:8; costal cell with single complete row of setae: basal cell with single seta in right wing, without seta in left wing; basal vein with four setae in left wing, two in right. Petiole length 1.6X width (12.5:8.0); with four pairs of lateral setae directed anteriolaterally. Gaster length 1.4X width (38:27); hind margin of Tl emarginate mesally; hypopygium extending to end of T7. Allotype, male. — Color: Similar to holotype except all metallic areas dark blue. Structure: Body length 1.8 mm. Head width 2.4X length (31:13). Antenna with length of pedicel plus flagellum 1 . 1 X head width (35:31); ratio of lengths of scape, pedicel, annelli, Fl-6, club as 10.0:3.0: 1 .0:4.0:4.0:3.5:4.0: 3.5:3.5:8.5; widths of Fl, F6, club as 3:3:3; MPP Figures 1-2. Syntomopus species. 1, americanus, female clypeus. 2, arpedes, female habitus. 112 Journal of Hymenoptera Research sensilla short, extending less than 1/2 length of funicular segments, only one or two visible per segment at a time; flagellar pilosity dense, fine, semierect. Petiole length 1 .8X width ( 1 1 :6). Gaster length 1.1X width (20:18). Variation. — The body color of the males varies from blue, like in the allotype, to green, like in the holotype. The body length of the females varies from 1.7 to 2.3 mm, and the body length of males varies from 1 .8 to 2. 1 mm. The ratio of head width divided by length averages 2.62±(S.E.=)0.029 (n=ll, range=2.5-2.8) for females and 2.5±0.023 (n=8, range=2.4-2.5) for males. Two of 12 females have setae on the basal vein and three of seven males do, but only one or two setae are usually present. Discussion. — This species is similar to S. americanus, but the difference in the head shape, particularly of the females, is quite distinct (com- pare Figs. 3 & 4). The ratio of head width to length varies from 2.5-2.8 for females and 2.4-2.5 for males of S. arpedes, but from 2.2-2.4 for females and2.1-2.4formalesofS. americanus. In addition, the vertex of S. arpedes females has a pinched appearance, while the vertex of S. americanus females is more evenly rounded anterioposterior^. From the descriptions in De Santis et al. (1976), S. arpedes most closely resembles S. parisii in having the dorsum of the thorax very flat and the pronotum with the humeral angles squared. S. arpedes differs from S. parisii in having the scape metallic to the base and the side denticles of the clypeus much reduced compared to the central denticle. S. parisii has the scape yellow and the middle denticle of the clypeus only a little larger than the lateral denticles. Txpe Material.— The holotype (USNM), allo- type (USNM), and six female and three male paratypes (CMNH, USNM) were reared from a Zinnia stem borer in September 1940 by R. M. Bohart in Westwood Hills, Los Angeles County, California. An additional 14 paratypes were col- lected as follows (INHS, UCDC, USNM): United States. ALABAMA: 1 9 . CALIFORNIA: 5 mi w. Yuba City, 5 & 1 1. II. 1971 [reared from Xanthium strumarium (Asteraceae)], 49, 26; Needles. 30.1.1977, 19; southern California, 11.IX.1950 (Zinnia plants), 1 6 . ILLINOIS: University of Illi- nois South Farms (nr. Champaign), 27. VI. 1981, 19. MARYLAND: Eldorado, 17.IX.1930 [ex. Epiblema strenuana infested Ambrosia (Asteraceae)], 1 9. TEXAS: Alpine, 30.VIII.1971 [Happlopapus (=Machaeranthera) gracilis (Asteraceae)], 1 9 . Mexico. NUEVO LEON: 9 mi s. Monterrey, 11.VIII.1972, 1 9 ; in car from Guaymas at Nogales, 22.IX.1950, 1 6. Etymology. — The species name is from the Greek arpedes, meaning even or flat, and refers to the flat head of this species. Biology. — The only determined host of S. arpedes is a tortricid lepidopteran, Epiblema strenuana (Walker) infesting Ambrosia (Asteraceae). Syntomopus arpedes has been reared in association with a number of Asteraceae, includ- ing Zinnia stem-borer material from Westwood Hills, California, Xanthium strumarium L. from near Yuba City, California, and from Machaeranthera gracilis (Nuttall) Shinners in Texas. Syntomopus americanus Ashmead Figs. 1 & 4 Syntomopus americanus Ashmead, 1894:51-52. Webster, 1894:36. Dalla Torre, 1898: 167. Figures 3-4. Syntomopus species. 3, arpedes, female head, dorsal view. 4, americanus, female head, dorsal view. Volume 2, Number 1, 1993 113 Nason, 1906:152. Schmiedeknecht. 1909:376. Girault, 1918:128. Glick, 1939:46. Hansberry. 1940:199, 711. Shread, Brigham. and Smith, 1 94 1 :495^96. Lange, 1944:394-395. Cassidy . Romney, Buchanan, and York, 1950:7. Peck, 1951:538. Peck, 1963:610. Burks, 1979:787. Syntomopus affinis Ashmead, 1896:228, syn. n. Dalla Torre, 1898:167. Nason, 1906:152. Schmiedeknecht, 1909:376. Girault. 1918:128. Peck, 1951:538. Peck, 1963:609-610. Burks, 1979:787. Ashmead ( 1 896) gave the following differences between S. americanus and his new species S. affinis: 1. Fl-5 elongate and F6 quadrate in S. americanus. while all the funicular segments trans- verse in S. affinis. 2. All the tibiae pale colored in S. americanus. while the middle and hind tibiae dark in 5. affinis. 3. The median emargination of Tl deep in S. americanus. but running almost to the base of the first tergum in S. affinis. The type of S. americanus was misidentified as a female; how- ever, and the differences listed above are those commonly found between males and females of a single common Nearctic Syntomopus species. The deeply cleft T 1 must have been an error in observa- tion because this state was not seen by me on the type or any other specimen of Nearctic Syntomopus. On the basis of my reexamination of the types of these two species and a comparison of the variation between the types and variation observed in other Nearctic Syntomopus material, I am synonymizing S. affinis with S. americanus. Discussion. — Compared with the Palearctic Syntomopus species, S. americanus most closely resembles S. incurvusaadS. thoracicus. Ma\esofS. americanus differ from males of these Palearctic species by having the funiculus more slender, with all its segments, except sometimes F6, elongate. All the male funicular segments, except Fl, are trans- verse in 5. thoracicus. while F4-6 are transverse in S. incurvus (Graham 1969). Syntomopus americanus females differ from 5. incurvus females by never having the anterior corners of the pronotum promi- nent and by having the stigmal vein shorter relative to the marginal vein. The length of the marginal vein averages 2.2±(S.E.=)0.023 (n=10) times that of the stigmal vein in S. americanus, but varies between 2.3 and 2.5 times in S. incurvus. Females of S. americanus have pale colored tibiae, not black like those of S. thoracicus. The ratio of head width divided by length averages 2.27±(S.E.=)0.025 (n= 1 0, range=2.2-2.4) for females and 2.27±0.020 (n=10, range=2. 1-2.4) for males of S. americanus. Material examined. — Syntomopus americanus is among the most commonly collected species of miscogasterine pteromalids, and I examined 224 specimens from the following U.S. states and Ca- nadian provinces and territories (ICCM, CNCI, FSCA, INHS, SEMC, UCDC. UCRC, USNM): Arizona. California. Colorado, Delaware, Florida, Illinois, Iowa, Idaho, Maryland, Massachusetts, Michigan. Minnesota, Missouri, New York, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah. Virginia, Washington, Alberta, Brit- ish Columbia, Manitoba. Ontario. Quebec, Nova Scotia, Yukon Territory. Biology. — Syntomopus americanus has been reared from a number of stem-mining Diptera, mostly Agromyzidae, but there is one record from a stem-boring cochylid lepidopteran. There is also a possible record from a cynipid gall on white poplar, but I believe that the gall of the poplar- galling agromyzid, Hexomyza schineri Giraud, was mistaken for a cynipid gall. The following is a list of host records from specimens examined: United States. CALIFORNIA: Salinas, 20.X.1943, Agromyza (=Melanagromyza) virens Loew (Diptera: Agromyzidae)(USNM). DELAWARE: Newark, 6 & 7. V. 1935. ragweed borer material(USNM). MICHIGAN: Gogebic Co.. 1 5. V. 1968, in gallery of Saperda concolorLeConte (Coleoptera: Cerambycidae)(USNM). NEW YORK: Ithaca, Winter 1925.1926, Agromyza (=Melanagromyza) virens (USNM); 21.11.1939, 6 & 15.111.1939, Agromyza (=Melanagromyza) angelicae Frost (Diptera: Agromyzidae)(USNM). OHIO: Eaton Mountain, 10 & 14.VI.1934, ex Agromyza (=Melanagromyza) virens (USNM). PENNSYLVANIA: 19. XI. 1939, ex stems of Vernonia noveboracensis (L.) Michaux (USNM). Canada. QUEBEC: St. Romuald, 13.VI.1958, Agromyza (=Hexomyza) schineri on Populus tremula tremuloides (Michaux) Loeve & Loeve (CNCI). MANITOBA: Falcon Lake, 8.VII.1965, cynipid[?] gall on white poplar (CNCI); Riding 114 Journal of Hymenoptera Research Mountain National Park, 7. VIII. 1966, cynipid[?] gall on white poplar (CNCI). NOVA SCOTIA: Simpson Field Station (Rest. Co.), 5. VIII. 1960, Agromyza (=Hexomyza) schineri (CNCI). ONTARIO: Ancaster, various dates in December 1966 and January 1977, Melanagromyza martini Spencer (CNCI), 19.XII.1966, Phytomyza flavicornis Fallen (Diptera: Agromyzidae) (CNCI); Vinland Station, 23.V.1936, ex Phalonia voxcana Kft. (Lepidoptera: Cochylidae) in stems of Prenanthes alba L.(CNCI); Windsor, 1948, Agromyza sp. in hollyhock [Melanagromyza hicksi Steyskal ?] (CNCI). In addition, Syntomopus americanus has been collected in association with the following plants: alfalfa at Mesa, Arizona; Ambrosia at Sioux City, Iowa and Maiden, Massa- chusetts; ragweed at St. David, Ontario; Helianthus annmis L. at Webster. Missouri; Salix at Sioux City, Iowa and Logan Canyon, Utah; Betula at 58 miles east of Dawson, Yukon; and Urtica dioica L. at Ancaster, Ontario. There are several host records for Syntomopus americanus in the literature. This species was reared in the spring from stems of Ambrosia trifida L., probably from pupae of Agromyza sp. (Webster 1894). Syntomopus americanus emerged in Janu- ary and February along with adults of its host from pupae in stems of hollyhock. Althaea rosea (L.)(Malvaceae), in the lab (Hansberry 1940). The host is given as Agromyza (^Melanagromyza) angelicae Frost; however, this agromyzid is a stem borer in Angelica spp. (Spencer and Steyskal 1 986). The stem-mining agromyzid of hollyhock is Melanagromyza hicksi Steyskal and this may be the actual host in the study of Hansberry ( 1 940). Schread et al. (1942) reported Syntomopus americanus as a primary parasite of dipterous larvae in stems of the dwarf ragweed. Ambrosia artemisiaefolia L. Syntomopus americanus was also given as a major parasite of Agromyza (-Melanagromyza) virens puparia in stems of guayule, Parthenium argentatwn Gray(Asteraceae)(Lange 1944;Cassidyetal. 1950). Parasite records of Syntomopus americanus in the studies by Webster, Hansberry , Lange, and Cassidy et al. were verified by me through examination of voucher material in collections. ACKNOWLEDGEMENTS I wish to thank the following persons for the loan of material used in this study: G. A. P. Gibson. Canadian National Collection (CNCI); G. C. Eickwort, Cornell University (CUIC); L. A. Stange, Florida State Collec- tion of Arthopods (FSCA); G. E. Wallace, Carnegie Museum of Natural History (ICCM); W. E. LaBerge. Illinois Natural History Survey (INHS); R. Brooks, Snow Entomological Collection at the University of Kansas (SEMC); J. D. Pinto, University of California at Riverside (UCRC); E. E. Grissell, United States Na- tional Museum (USNM). The acronym used for the collection of the Bohart Museum at the University of California at Davis is UCDC. Thanks also go to both Dr. R. McGinley and the Smithsonian Institution for the Smithsonian Postdoctoral Fellowship and to Dr. D. Miller and the U.S. Department of Agriculture for sup- port during the research phase of this project. LITERATURE CITED Ashmead, W. H. 1894. Descriptions of thirteen new parasitic Hymenoptera, bred by Prof. F. M. Webster. Journal of the Cincinnati Society of Natural History 17:45-55. Ashmead, W. H. 1896. Descriptions of new parasitic Hymenoptera. Transactions of the American Ento- mological Society 23: 179-234. Ashmead, W. H. 1904. Classification of the chalcid flies or the Superfamily Chalcidoidea, with descriptions of new species in the Carnegie Museum, collected in South America by Herbert H. Smith. Memoirs of the Carnegie Museum l:i-ix, 225-551, pis. 31-39. Askew, R. R. 1970. Observations on the hosts and host food plants of some Pteromalidae [Hym., Chalcidoidea]. Entomophaga 15:379-385. Boucek, Z. 1976. African Pteromalidae (Hymenoptera): new taxa, synonymies and combinations. Journal of the Entomological Society of Southern Africa 39:9- 31. Boucek, Z. 1988. 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CatalogusHymenopterorum hucusque descriptorum systematicus etsynonymicus. Vol. 5. Chalcididae et Proctotrupidae. Leipzig. 598 pp. De Santis, L., N. B. Diaz, and I. del Carmen Redolfi. 1976. La mosca del girasol (Diptera, Agromyzidae) y sus himenopteros parasitoides. Dusenia 9:31-38. Dzhanokmen, K. A. 1978. [Identification of the insects of the European part of the USSR. Vol. 3. Hy- menoptera. Second Part. Pteromalidae.]. Opredeliteli Faune USSR 120:57-228. Forster, A. 1856. Hymenopterologische Studien. Vol. 2. Chalcidiae und Proctotrupii. Ernst ter Meer, Aachen. 152 pp. Girault, A. A. 1918. New and old West Indian and North American chalcid-flies ( Hym. ). Entomological News 29:125-131. Girault, A. A. 1926. New pests from Australia, IV. A. A. Girault: Brisbane. 2 pp. Glick, P. A. 1939. The distribution of insects, spiders, and mites in the air. United States Department of Agriculture. Technical Bulletin 673:1-150. Graham, M. W. R. de V. 1969. The Pteromalidae of north-western Europe ( Hymenoptera: Chalcidoidea). Bulletin of the British Museum (Natural History) Entomology, Supplement 16:1-908. Hansberry . R. 1 940. A new pest of hollyhock {Anthomyza angelicae Frost). Journal of Economic Entomology 33:199. Havranek, D. 1 987 . Melanagromyza tomaterae ( Diptera: Agromyzidae) a tomato pest in the states of Tachira and Merida, Venezuela. Florida Entomologist 70:294-295. Hedqvist, K.-J. 1972. Notes on Chalcidoidea (Hym.). I. The genus Syntomopus Walk. (Pteromalidae, Miscogasterinae.Sphegigasterini). Entomologisk Tidskrift 93:210-215. Heydon, S. L. 1988. The Sphegigasterini: A cladistic analysis and generic classification with reviews of selected genera (Hymenoptera: Pteromalidae). Ph.D. Thesis, University of Illinois, Urbana. Illinois (un- published). Heydon, S. L. 1989. Relationships among genera of the Cyrtogaster-group with a review of the species of North America north of Mexico (Hymenoptera: Pteromalidae ). 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Israel Program for Scien- tific Translations, Jerusalem. 593 pp. Peck, O 195 1 . Superfamily Chalcidoidea. pp. 410-594. In.C. F. W. Muesebeckand K. V. Krombein (Eds.). Hymenoptera of America North of Mexico — Synop- tic Catalog. Agricultural Monograph No. 2. United States Department of Agriculture. 1420 pp. Peck, 0. 1 963. A catalogue of the Nearctic Chalcidoidea. Canadian Entomologist. Supplement 30:1-1092. Peck. O.. Z. Boucek, and A. Hoffer. 1964. Keys to the Chalcidoidea of Czechoslovakia (Insecta: Hy- menoptera). Memoirs Entomological Society of Canada 34:1-120. Rudow.F. 1886. NonnulliPteromalini ado.de Stephani- Perez in Sicilia lecti. // Naturalista Siciliano 5:265- 268. Schmiedeknecht. O. 1909. Hymenoptera family Chalcididae. In, M. P. Wytsman (Ed.). Genera Insectorum. Vol. 97. M. P. Wytsman. 550 pp., 8 pis. Schread. J. C, W. T. Brigham, and G. R. Smith. 1942. Alternate host study of the parasites of the oriental fruit moth. Connecticut Agricultural Experiment Station Bulletin (New Haven) 461:490-502. Spencer, K. A., and G. C. Steyskal. 1 986. Manual of the Agromyzidae (Diptera) of the United States. United States Department of Agriculture, Agricultural Hand- book 638:1^178. 116 Journal of Hymenoptera Research Thomson, C. G. 1 878. Hymenoptera Scandinaviae. Vol. 5. Pteromalus (Swederus) continuatio. H. Ohlsson, Lund. 307 pp. Walker, F. 1833. Monographia Chalcidum. Entomo- logical Magazine 1:367-384. Webster, F. M. 1 894. Biological notes on reared para- sitic Hymenoptera of Ohio and Indiana, with descrip- tions of thirteen new species, by W. H. Ashmead. Journal of the Cincinnati Society Natural History 17:34-45. Westwood, J. O. 1 839. Synopsis of the genera of British insects. 1-158 pp. Bound with, Westwood, J. O. ( Ed. ). An introduction to the modern classification of insects: founded on the natural habits and corre- sponding organization of the different families. Vol. 2. Longman, Orme, Brown, Green, and Longmans. J. HYM. RES. 2(1), 1993 pp.1 17-168 Systematic studies on Pseudomyrmex acacia-ants (Hymenoptera: Formicidae: Pseudomyrmecinae) Philip S. Ward Department of Entomology. University of California. Davis. CA 95616 Abstract. — The obligate acacia-ants ( Pseudomyrmex ferrugineus group) are well known as defensive inhabitants of swollen-thorn acacias in the northern Neotropics. A taxonomic revision of these ants leads to the recognition of ten species: P. ferrugineus (F. Smith), P. flavicornis (F. Smith), P. janzeni, sp. nov., P. mixtecus, sp. nov., P. nigrocinctus (Emery), P. particeps, sp. nov., P. peperi (Forel), P. satanicus (Wheeler), P. spinicola (Emery), and P. veneficus (Wheeler). The following new synonymy is proposed: P. nigrocinctus = P. alfari (Forel) = P. bicinctus (Santschi) = P. peltatus (Menozzi); P. spinicola = P. atrox (Forel) = P. gaigei (Forel) = P. infernalis (Wheeler) = P. scelerosus (Wheeler). Diagnostic descriptions and taxonomic comments are also provided for ten other unrelated species of Pseudomyrmex which have become secondarily associated with swollen-thorn acacias either as obligate and, in at least one case, parasitic occupants (P. nigropilosus (Emery), P. simulans Kempf and P. subtilissimus (Emery); P. reconditus, sp. nov., may also belong in this category ) or as facultative inhabitants ( P. boopis (Roger), P. gracilis (Fabricius), P. hesperius, sp. nov., P. ita (Forel). stat. nov., P. kuenckeli (Emery) and P. opaciceps, sp. nov.). A cladistic analysis of the P. ferrugineus group yields the following result which appears to be fairly robust insofar as there is congruence among the trees derived from worker-, queen-, and male-based character sets: {(nigrocinctus + particeps) + {peperi + ({satanicus + spinicola) + ferrugineus complex))). The "ferrugineus complex" comprises five species whose phylogenetic relationships are not fully clarified. The composite data set (47 characters from all three castes) supports the following partial resolution: {ferrugineus + janzeni + {flavicornis + {mixtecus + veneficus))). The cladogram of the P. ferrugineus group indicates that speciation in the group has occurred primarily as a consequence of geographical isolation, and that the ants and their host acacias have experienced diffuse coevolution rather than strict cospeciation. INTRODUCTION merits have appeared in the ecological literature. In this paper I present a taxonomic revision of the Pseudomyrmex ferrugineus (F. Smith) and re- obligate acacia-ants {Pseudomyrmex ferrugineus lated species of ants form a well-defined mono- group) and an assessment of their phylogenetic phyletic group, the members of which nest exclu- relationships. I also attempt to clarify the identities sively in the hollow, swollen thorns of several New of other, unrelated species of Pseudomyrmex which World Acacia species. Because of their aggressive have become secondarily associated with swollen- behavior and predictable occurrence on the acacias, thorn acacias. these ants have received considerable attention The earlier taxonomic literature on acacia-ants from tropical biologists (Belt 1874; Safford 1922; is scattered in more than a dozen papers containing Skwarra 1934a. 1934b; Wheeler 1942; Janzen 1966, descriptions of various species, subspecies, and 1973). The landmark studies of Janzen (1966, "varieties". Two of the more comprehensive treat- 1967b) provided strong experimental evidence of ments are those of Emery (1890) and Wheeler the mutualistic nature of the Pseudomyrmex/ Aca- ( 1942). In presenting the results of his ecological cia association, and the relationship between the studies Janzen (1966, 1967b, 1973) summarized two organisms is often cited in discussions of his understanding of acacia-ant taxonomy. Ward coevolved mutualisms (e.g. Gilbert 1983; Beattie (1989) provided a brief diagnosis of the P. 1985; Futuyma 1986). At the same time, the ferrugineus group, together with taxonomic and systematics of the acacia-ants has been neglected, nomenclatural notes on the commoner species, with the result that misidentifications and misstate- 118 Journal of Hymenoptera Research CISC CUIC MATERIALS AND METHODS Collections Material for the present study was examined in the following collections: AMNH American Museum of Natural History, New York, NY, USA ANSP Academy of Natural Sciences, Philadel- phia, PA. USA BMNHThe Natural History Museum, London, U.K. CASC California Academy of Sciences, San Fran- cisco, CA, USA CHAH C.H.A. Hespenheide Collection, Univer- sity of California at Los Angeles, C A, USA California Insect Survey, University of California at Berkeley, CA, USA Cornell University Insect Collection, Ithaca, NY, USA EBCC Estacion de Biologfa Chamela, Jalisco, Mexico FFIC Fernando Fernandez Collection, Santa Fe de Bogota, Colombia GBFM Graham B. Fairchild Museo de Invertebrados, Universidad de Panama, Panama GCWC G.C. & J. Wheeler Collection, Silver Springs, FL, USA Instituto Nacional de Biodiversidad (col- lections previously held in MNCR: Museo Nacional de Costa Rica), San Jose, Costa Rica Illinois Natural History Survey Insect Col- lection, Champaign, IL, USA J.T. Longino Collection, Evergreen State College, Olympia, WA, USA KSUC Kansas State University Insect Collection, Manhattan, KS, USA LACM Natural History Museum of Los Angeles County, Los Angeles, CA, USA MCSN Museo Civico di Storia Naturale, Genoa, Italy MCZC Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA MHNG Museum d'Histoire Naturelle, Geneva, Switzerland MNHN Museum National d'Histoire Naturelle, INBC INHS JTLC MZSP NHMB NHMV PSWC SEMC UCDC UCRC USNM WPMC ZMHB ZMUC ZMUH ZSMC Paris, France Museo de Zoologia da Universidade de Sao Paulo, Brazil Naturhistorisches Museum, Basel, Swit- zerland Naturhistorisches Museum, Vienna, Aus- tria P.S. Ward Collection, University of Cali- fornia at Davis, CA, USA Snow Entomological Museum, University of Kansas, Lawrence, KS, USA Bohart Museum of Entomology, Univer- sity of California at Davis, CA, USA UCR Entomological Collection, Univer- sity of California at Riverside, CA, USA National Museum of Natural History, Washington, DC, USA W.P. MacKay Collection, El Paso, TX, USA Zoologisches Museum, Museum fur Naturkunde der Humboldt-Universitat, Berlin. Germany Zoologisk Museum, University of Copenhagen, Denmark Zoologisches Institut und Zoologisches Museum der Universitat Hamburg, Ger- many Zoologische Staatssammlung, Munich, Germany Special mention should be made of the very large and important series of Pseudomyrmex col- lected by D.H. Janzen from 1963 to 1974 and now housed in the Natural History Museum of Los Angeles County (LACM). The Janzen material includes a large number of pinned specimens (usu- ally glued to the side of the pin rather than point- mounted ) and an extensive alcohol collection (partly overlapping with the pinned series but including additional accessions). Janzen's field notes per- taining to the collection of these ants have also been deposited in LACM. Obligate acacia-ants (P. ferrugineus group) constitute the bulk of the col- lected material. They occur as long nest series from throughout Central America, with very useful queen- male-worker associations, making this material of inestimable value to the current revision. Volume 2, Number 1, 1993 119 When the Janzen collection was received at LACM in 1984 most specimens had only code numbers associated with them — among the pinned specimens a single individual per nest series typi- cally contained a code number, with the remaining specimens being unlabelled — and in some instances difficulties arose in retrieving full data for coded specimens from Janzen' s field notes. In other cases the field notes contradicted the apparent identity or composition of a nest series. This latter problem applied mainly to pinned specimens; the alcohol material appeared to be reliably labelled or coded, i.e. the contents of the vials agreed with the field notes. Thanks to the efforts of Roy Snelling and Jack Longino, who incorporated the Janzen collec- tion into the LACM, many of these discrepancies or uncertainties were resolved, but there remains a residue of "problem material" for which collection data are lacking or ambiguous. Among the pinned specimens this comprises twelve drawers in the LACM collection which have been specifically set aside from the main collection. None of this prob- lematical material has been cited in the present study, but I have examined it and determined that no additional species are represented there. Al- though omission of this material means the poten- tial loss of some locality data, I have examined the entire alcohol collection and point-mounted repre- sentative samples so that geographic coverage re- mains extensive. The main pinned series of LACM acacia-ants, i.e. that for which accurate data labels are available, comprises 30 drawers and approxi- mately 20,000 specimens, the great majority of which were collected by Janzen. Metric Measurements and Indices All measurements were made under a Wild microscope at 50X power, using an orthogonal pair of Nikon micrometers wired to a digital readout. Measurement conventions follow those described in Ward (1985, 1989). Note that a full-face or dorsal view of the head involves positioning the posterior margin and the anterolateral margins (above the mandibular insertions) so that they lie in the same plane of view. The following measurements and indices are cited in this study (the first six measurements are taken with the head in a full-face, dorsal view): HW Head width: maximum width of head, in- cluding the eyes. VW Vertex width: width of the posterior portion of the head (vertex), measured along a line drawn through the lateral ocelli. HL Head length: midline length of head proper, from the anterior clypeal margin to the mid- point of a line drawn across the •'occipital" (i.e. posterior) margin. EL Eye length: length of compound eye; note that this is measured with the head in full face, dorsal view, unlike EW(below). OD Ocellar distance: distance from the middle of the median ocellus to the midpoint of a line drawn between the lateral ocelli. OOD Oculo-ocellar distance: distance from the middle of the median ocellus to the midpoint of a line drawn across the posterior margins of the compound eyes (this distance is nega- tive in value if the posterior margin of the compound eye exceeds the median ocellus). MFC Minimum frontal carinal distance: minimum distance between the frontal carinae, poste- rior to their fusion with, or approximation to, the antennal sclerites. ASD Antennal sclerite distance: maximum dis- tance between the lateral margins of the me- dian lobes of the antennal sclerites, measured in full-face, dorsal view of the head. ASO Antennal sclerite distance, outer margins: maximum distance between the outer, lateral margins of the antennal sclerites. CLW Width of median clypeal lobe, measured between the anterolateral angles (in Pseudomyrmex satanicus and P. spinicola only; see Figs. 10, 11). MD4, MD5. MD8. MD9 A series of mandibular measurements (see Ward 1989, figure 2). MD4: distance along the basal margin of the mandible from the base to the mesial basal tooth; MD5: length of the basal margin; MD8: distance along the masticatory margin from the apex to the fourth tooth, counting from the apex; MD9: length of the masticatory margin. 120 Journal of Hymenoptera Research PL WF2 FL FW DPL BF DF MP PH EW Eye width: maximum width of compound eye, measured along its short axis in an oblique dorsolateral view of the head. SL Scape length: length of the first antennal segment, excluding the radicle. LF1 Length of first funicular segment: maximum measurable length of the first funicular seg- ment (pedicel), including its basal articula- tion in workers and queens but excluding the basal articulation in males (where it is usu- ally hidden). LF2 Length of second funicular segment: maxi- mum measurable length of the second funicular segment. LF3 Length of third funicular segment: maxi- PPL mum measurable length of the third funicular segment. Width of second funicular segment. Profemur length: length of the profemur, measured along its long axis in posterior view (see Ward 1985, figure 3). Profemur width: maximum measurable width of the profemur, measured from the same view as FL, at right angles to the line of measurement of FL. Diagonal length of the propodeum: length of the propodeum, measured in lateral view along a diagonal line drawn from the "metapleural" lobe to the metanotal groove (see Ward 1985, figure 2). Length of the basal (=dorsal) face of the propodeum, measured in lateral view from the metanotal groove to the point on the surface of the propodeum which is maxi- mally distant from the diagonal propodeal line. Length of the declivitous face of the propodeum, measured in lateral view from the "metapleural" lobe to the point on the surface of the propodeum which is maxi- mally distant from the diagonal propodeal line. Depth of metanotal groove ("mesopropodeal impression"), measured in lateral view from the bottom of the metanotal groove to a line drawn across the dorsal surface of the mesonotum and propodeum. Petiole length: length of the petiole, mea- sured in lateral view from the lateral flanges of the anterior peduncle to the posterior mar- gin of the petiole (see Ward 1985, figure 4). PND Petiolar node distance: distance from the lateral flanges of the anterior petiolar pe- duncle to the maximum height of the node, measured from the same view as PL and along the same line of measurement (see Ward 1985, figure 4). Petiole height: maximum height of the peti- ole, measured in lateral view at right angles to PL, but excluding the anteroventral pro- cess. Postpetiole length: length of the postpetiole, measured in lateral view, from the anterior peduncle (of the postpetiole) to the point of contact with the fourth abdominal tergum, excluding the pretergite (see Ward 1985, figure 4). DPW Dorsal petiolar width: maximum width of the petiole, measured in dorsal view. MPW Minimum petiolar width: minimum width of the petiole, measured in dorsal view, anterior to DPW. PPW Dorsal postpetiolar width: maximum width of the postpetiole, measure in dorsal view. LHT Length of metatibia: maximum measurable length of metatibia, excluding the proximal part of the articulation which is received into the distal end of the metafemur (see Ward 1989, figure 5). CI Cephalic index: HW/HL 01 Ocular index: EW/EL REL Relative eye length: EL/HL REL2Relative eye length, using HW: EL/HW 001 Oculo-ocellar index: OOD/OD VI Vertex width index: VW/HW FCI Frontal carinal index: MFC/HW FCI2 Frontal carinal index, using ASD: MFC/ASD ASI Antennal sclerite index: ASD/ASO SI Scape index: SL/HW SI2 Scape index, using EL: SL/EL FLI Funicular length index: (LF2 + LF3)/WF2 FI Profemur index: FW/FL PD1 Propodeal index: BF/DF MPI Metanotal index: MP/HW NI Petiole node index: PND/PL Volume 2, Number 1, 1993 121 PLI PLI2 PWI PWI2 PWI3 PWI4 PPWI Petiole length index: PH/PL Petiole length index, using PPL: PPL/PL Petiole width index: DPW/PL Petiole width index, using PPW: DPW/PPW Petiole width index, using MPW: MPW/ DPW Petiole width index, using LHT: DPW/ LHT Postpetiole width index: PPW/PPL Other Conventions Other terminology follows the usage in Ward (1989). Note that descriptions of surface sculpture and integument reflectance apply to observations made under soft light, with an opaque ( Mylar) filter placed between the specimens and source of illumi- nation. Palp formula refers to the number of max- illary palp segments followed by the number of labial palp segments; 5p4,3 indicates a condition intermediate between 5,3 and 4,3, i.e. partial fusion of the fourth and fifth maxillary palp segments. Listing of synonymy under each species is re- stricted to citation of the original descriptions (with full reference given for all previously proposed junior synonyms) and new nomenclatural combi- nations. For ecologists a more useful summary of name usage is offered in Table 1, which indicates the correspondences between the names appearing in the biological literature on acacia-ants and the currently valid scientific names. The reader will appreciate that there has been considerable misidentification of these ants. In the lists of material examined of each species, I have cited only locality and collector ("c.u." signifies collector unknown), with the source col- lections listed together at the beginning. Additional locality information is sometimes provided in square brackets, to facilitate location of the collecting site. Considerable effort was expended to determine the coordinates (latitude and longitude) of each collect- ing site, and this was then used in conjunction with the public domain software program Versamap (version 1.20) to plot the distributions of each species (Figs. 67-72). Cladistic Analysis A set of 47 characters, representing the most discrete or quantifiable differences among species or groups of species in the P. ferrugineus group, was used for phylogenetic analysis. Twenty of these characters were worker-based ( 1 1 of these manifested the same conditions in queens), 8 were queen-based, and 19 were taken from male mor- phology, primarily male genitalia. The characters and character states are as follows: 1. Worker, median clypeal lobe (0) laterally rounded or subangulate, ( 1 ) laterally with sharp angles or teeth (Figs. 10, 11). 2. Worker and queen, frontal carinae (0) rela- tively well separated, median lobes of anten- nal sclerites less exposed ( Figs. 1 2- 1 9, 32), ( 1 ) closely adjacent and median lobes of antennal sclerites more exposed (Figs. 10, 1 1, 32). 3. Worker and queen, palp formula (0) 5,3, ( 1 ) 4,3. 4. Worker, head (0) broader, relative to HL, DPL and PL, (1) narrower; see regressions of HL, DPL and PL on HW (Figs. 36-38). 5. Worker, scape (0) short, relative to HL. ( 1 ) longer; regression of SL on HL lying above that of other species. 6. Worker, conspicuous pit-like impression on midline of head (0) absent. ( 1 ) present. 7 . Worker, petiole ( 0 ) short relative to postpetiole. PLI2 0.77, ( 1 ) longer relative to postpetiole, PLI2<0.77. 8. Worker and queen, petiole (0) without a well differentiated anterior peduncle, i.e. weakly constricted in dorsal view and with little or no inflection of the anterior face of the petiole in lateral profile (Figs. 22, 23), ( 1 ) with a well differentiated peduncle (Figs. 20, 21, 24-29). 9. Worker and queen, petiole, dorsal view, angulate posterolateral corners (0) absent, (1) moderately developed, preceded by convex or sinuate sides (e.g. Figs, 20, 27), (2) very promi- nent, preceded by more or less straight sides (Fig. 24). 10. Worker and queen, petiole (0) shorter and higher, worker PLI 0.71, queen PLI 0.64, 122 Journal of Hymenoptera Research ( 1 ) more slender, worker PLI < 0.72. queen PLI < 0.64. 1 1 . Worker, DPW relative to HW (0) narrow, ( 1 ) broader, (2) very broad; see regression of DPW on HW (Fig. 41). 12. Worker, plot of PWI3 by HW lying in (0) upper left ( 1 ) lower right (2 ) lower left region, of Fig. 39. 1 3. Worker and queen, plot of PWI4 by HW lying in (0) center and lower right ( 1 ) upper left (3) lower left region, of Fig. 40. 14. Worker, postpetiole (0) broad, PPWI > 1.30, ( 1 ) narrow, PPWI 1.00-1.30. 1 5. Worker, metatibia (0) short, relative to HL, ( 1 ) relatively long; see regression of LHT on HL (Fig. 30). 1 6. Worker and queen, head sculpture (0) densely punctulate, subopaque to sublucid, at least on upper third of head, ( 1 ) densely punctulate. opaque, (3) punctulate-coriarious, opaque (matte). 17. Worker and queen, propodeum, posterolat- eral portions (0) sublucid. without overlying rugulo-punctate sculpture, ( 1 ) supopaque to opaque, with rugulo-punctate sculpture. 18. Worker and queen, petiolar node (0) lacking conspicuous suberect pubescence, ( 1 ) with such pubescence. 1 9. Worker and queen, standing pilosity on exter- nal faces of tibiae (0) present, ( 1 ) absent. 20. Worker and queen, head and gaster (0) yel- low- to orange-brown, ( 1 ) reddish-brown to medium or dark brown, ( 2 ) very dark brown to black (excluding mandibles, clypeus and scape). 21. Queen, size (0) small, HW 0.85, ( 1 ) medium to large, HW 0.85. 22. Queen, head shape, for a given LHT (0) elon- gate, ( 1 ) less elongate, (2) broad (see Fig. 52). 23. Queen, petiole (0) short, relative to HW, PL/ HW < 0.71,(1) longer, PL/HW 0.71. 24. Queen, petiole (0) short, relative to HL, ( 1 ) longer: see regression of PL on HL (Fig. 46). 25. Queen, regression of PH on HW lying in (0) upper ( 1 ) middle (2) lower region, in Fig. 47. 26. Queen, petiole, dorsal view (0) narrow, rela- tive to HL, (2) broader; regression of DPW on HL lying above that of other species. 27. Queen, metatibia (0) short, relative to HL, LHT/HL < 0.62, ( 1 ) longer, LHT/HL > 0.66. 28. Queen, metatibia (0) short, relative to HW, ( 1 ) longer; see regression of LHT on HW (Fig. 31). 29. Male, head (0) narrower, CI 0.82-0.94 and HW < 0.96, ( 1 ) broader, CI 0.94 and/or HW 0.96 (regression of HL on HW lying below that of other species). 30. Male, scape index (SI) (0) 0.22-0.30. ( 1 ) 0.29- 0.35, and regression of SL on HW lying above that of other species. 3 1 . Male, scape length, relative to EL and HL (0) long, SI2 0.43-0.56, SL/HL 0.22, ( 1 ) shorter, SI2 0.33-0.43, SL/HL 0.21 (and regression of SL on HL lying below that of other species). 32. Male, compound eye length, relative to HW (0) long, REL2 0.56-0.63, (1) shorter, REL2 0.49-0.58, and regression of EL on HW lying below that of other species. 33. Male, petiole (0) less slender. PLI > 0.45, ( 1 ) more slender, PLI < 0.50, and regressions of PH and DPW on LHT lying below those of other species. 34. Male, sternite IX, posterior margin (0) con- vex, ( 1 ) with a moderate concavity, less than semicircular (Fig. 54), (2) with a deep, semi- circular concavity (Fig. 55). 35. Male, paramere, lateral view, posterodorsal extremity(O) rounded, ( 1 ) angulate or ex- panded. 36. Male, paramere, lateral view, posterodorsal extremity (0) not projecting caudad. ( 1 ) pro- jecting caudad, as in Figs. 56, 57. 37. Male, paramere, lateral view, posterodorsal extremity (0) not developed as a lobe-like protrusion, whose mesial face is a saucer-like concavity, ( 1 ) so developed (Figs. 61-66). 38. Male, paramere, lateral view, posterodorsal extremity (0) well separated from mesiodorsal lobe, ( 1 ) close to mesiodorsal lobe, enclosing a narrow space between it and the lobe (Figs. 58,61-66). 39. Male, paramere, digitiform mesiodorsal lobe (0) absent, ( 1 ) present, slender, directed poste- Volume 2, Number 1, 1993 123 riorly or posterodorsally (Figs. 56-60, 63-65 ), (2) present, stubby, directed more or less dor- sally (Figs. 61, 62). 40. Male, paramere, mesial face of posterodorsal extremity (0) simple in form, not expanded mesially, ( 1 ) expanded mesially, partly ob- scuring the mesial dorsoventral ridge in poste- rior view. 41. Male, aedeagus, posterior margin (0) entire, not medially pointed, ( 1 ) toothed, and medi- ally pointed. 42. Male, aedeagus, posterior margin (0) bent posterolaterally, ( 1 ) bent anterolateral^, (2) bent anterolaterally but with the medial point redirected posteriorly. 43. Male, aedeagus, laterally bent portion of pos- terior margin (0) continuous with the margin of the posterodorsal extremity.! 1 ) discontinu- ous with margin of posterodorsal extremity (elevated laterally), the two connected by a gradual slope, (2) discontinuous with margin of posterodorsal extremity, elevated laterally, and separated by a trenchant rise (posterior view) from the posterodorsal extremity. 44. Male, aedeagus, plate-like expansion of posterodorsal extremity (0) absent, ( 1 ) mod- erately developed, (2) strongly developed. 45. Male, aedeagus, external face (0) without a large, central elevated area, (1) with a central elevated area, delimited posteroventrally by a weak ridge or carina, (2) with a central el- evated area, delimited posteroventrally by a strong lamellate carina. 46. Male, aedeagus, external face, afore-men- tioned carina (if present) (0) well separated from the toothed posterior margin, ( 1 ) running close to and more or less parallel with the toothed posterior margin but separated by a deep groove, (2) converging posterodorsally with the toothed posterior margin. 47. Male, aedeagus, posteroventral extremity (0) broadly rounded, ( 1 ) subangulate, ( 2 ) angulate with a tooth-like protrusion. The data set was analyzed using Fairis' Hennig86 program. Characters 12, 13 and 1 6 were considered unordered. As an outgroup I chose Pseudomyrmex fervidus (F. Smith), a Central American species which shares a number of (mostly worker) features in common with the P. ferrugineus group: 5,3 palp formula, similar mandibular dentition, well devel- oped metanotal groove, abundant pilosity on mesosoma dorsum, relatively small eyes, and a similar habitus with respect to size and color. In a few instances the outgroup species spanned the phenotypic gap between two discrete states in the ingroup; it was then coded as unknown for that character. In addition to seeking the most parsimo- nious tree for the entire data set (rooted with the outgroup), I also compared the cladograms based on three subsets, derived from the worker, queen, and male characters sets, respectively. For this second analysis the queen character set included the eight characters assessed only in queens (2 1 -28) plus those manifested identically in workers and queens (2, 3. 8-10, 13, 16-20), for a total of 19 characters. 124 Journal of Hymenoptera Research Figs. 1-9. Pseudomyrmex workers, lateral view of mesonotum, propodeum and petiole, with pilosity shown in outline; Figs. 4 and 5 include a frontal view of worker head. 1 , P. boopis (Costa Rica); 2, P. ita (Costa Rica): 3, P. kuenckeli (Costa Rica); 4, P. hesperius (Mexico, paratype); 5. P. opaciceps (Guatemala, paratype); 6, P. gracilis (Mexico); 7. P. nigropilosus (Costa Rica); 8. P. reconditus (Nicaragua, holotype); 9, P. simulans (Panama). Volume 2, Number 1, 1993 125 1 mm Figs. 10-19. Pseudomyrmex ferrugineus group, workers, full-face dorsal (=frontal) view of head with pilosity shown in outline (except on mandibles); Fig. 19 includes a lateral view of head. 10, P. satanicus (Panama); 1 1. P. spinicola (Costa Rica); 1 2, P. peperi (Guatemala); 1 3, P. nigrocinctus (Costa Rica); 14, P. particeps (Costa Rica, holotype); 15. P. mixtecus (Mexico, holotype); 16, P. flavicornis (Nicaragua); 17, P. veheficus (Mexico); 18, P. ferrugineus (Mexico); 19. P. janzeni (Mexico, holotype). 126 Journal of Hymenoptera Research -V~ 1 mm Figs. 20-29. Pseudomyrmex ferrugineus group, workers, dorsal view of petiole paired with lateral view of mesonotum, propodeum, petiole and, in Fig. 28, postpetiole. Standing pilosity shown in outline. 20, P. satanicus; 21, P. spinicola; 22, P. nigrocinctus; 23, P. particeps; 24, P. peperi; 25, P. flavicornis; 26, P. mixtecus; 27, P. ferrugineus; 28, P. veneficus; 29, P.janzeni. These are the same individuals illustrated in Figs. 10-19. 127 workers spinicola, satanicus - D other species 31 queens + spinicola, satanicus 1.4- D other species ♦ 1.3 - ♦ + ** * 1.2 - ♦ * V * + + /cPn t.1 - :'v*i^ 1 - $$** 0.9 - D DO ye 08 - " o o 0 7 - n — r 1 1 1 — — i — 32 workers + spinicola, satanicus □ other species ft!-, n o a ^ o a °„ B ° *-B 6?B °0 D a oe°# ft„D Don 0 % ibdo J workers 0.28 - + X □ spinicola, northern popns. spinicola, southern popns. satanicus 0 27 - P 0.26 - X ♦ a i u 0 25 - X X X + "* o d a D 0 24 - 0 23 -< x x + x + a o 0 °0 Q ° O 0.22 - + x + 021 - 0.94 0 98 102 1.06 1 14 1 18 1.22 1.26 workers 1.35 - + spinicola, northern popns. X spinicola, southern popns. o 1 3 - 1 25 - 1.2 - 1 15 - □ satanicus * * x x xx X * ♦ X* X + * ♦a d B * D D 0 a o 11 - x xx xxx + 1.05 - * 1 - X 0.95 - , , ~T 1 1 1 1 i 1 35 0 94 0 98 1 02 1.06 i 14 1 IB 1.22 1.26 workers D + spinicola. northern popns. o D 0 78 - X spinicola. st mt hern popns. □ satanicus ° DD 0.74 - 0.72 - * 0.7 - xx * + + * + O a + 0.68 - 0.66 - 0.64 - ** X xx x + a ♦ D 0.62 - X * + 0.6 - + 0 58 - + 0.56 - X * 0 54 - * + 0 52 0. 4 0.98 1 02 .06 i.i 1.14 1 18 1.22 1.26 36 workers peperi nigrocinctus, purticcps I others ° a, °o a 1 '■'Bi workers D a 1 05 - + peperi ■ nigrocinctus, particeps I - D others 0.95 - g o^o at, 0.9 - + + +Vt-*+ D<^$£rfi *^1^ o 0 8- 0.75 - D O 0.7 - x x x DO a 06 - 1 1 1 Figs. 30-37. Scattergram plots of various metric measurements and indices in workers and queens of the Pseudomyrmexferrugineus group, "other species" refers to all others in the P. ferrugineus group. 128 Journal of Hymenoptera Research 38° ' workers +■ pepen X nigrocincius, particeps 0.75 - a others "off ° 0.7 - "n? n,"> ° a ♦ + + o X"1*" °°°cP ao 0 6 - i **f* 9PqAjSo o 0.55 - 05 - *♦* < ° ° aj? o 0.45 - „ *** n OQ □ 0.4 - , , 1 1 1 39 0 6- x * workers x +- peperi M « **>txxx x nigrocincius, particeps 0.56 - O others 0.54 - 0.52 - * * a G 0 5 - * ° °d. °o o D42 - ++ G 0 4- 0.38 - 0.36 - + j * fl (9 * WtL fl* o g 0 34 - 03° ^^gLj^1 X 8 0 "111° O n°3b 0 0 3 - *♦ *x °° 0.28 - x Bf>x o 0 26 - 3&» x^x O 0.24 - x * 0 22 - * 1 1- 1 1 1 42 workers ♦ 0.49 - 0.48 - + paniceps D nigrocincius ♦ ♦ 0.47 - + • 0.46 - +. 0.45 - * 0.44 - 0.43 - 0.42 - * a * o a CD D a □ 0 G D O a a 0 41- a a 0.4 - 0.39 - G 43 091 0.93 095 097 0 99 1.01 103 1.05 107 1.09 workers * 0 49 - 0.48 - + a particeps nigrocincius + ♦ 0.47 - ♦ 0.46 - ♦ 0.45 - 4 0.44 - 0.43 - 0.42 - * + a a OqD o a a a a G a 0° 0.41 - d a a 0 4 - D 0.39 - -, . 1 — T 1 1 1 0 72 LHT 44^: O 7 0.68 0.66 - 0.64 - 062 0-6 - 0.58 - 056 0.54 - 0.52 ■ 05 • 0.4B - 0.46 - 0.44 - 0 42 - 0 85 workers • veneficits : mixtecus ] flavicornis 45 workers a 0.45 - + veneficus a a 0.44 - X mixtecus 0 43 - LI flavicornis 0.42 - ° a 0 0 41- 0 4- a 9 a - o°* 0.39 - 0.38 - 0 37 - 0.36 - 0 35 - X X «" 0 G 0 a 0 0 0 □ 0.34 - * 0 0.33 - 0 0.32 - 0.31 - 0 3 - 0.29 - k + □ 0 28 - £ 0.27 - 1 , — , — — , r 1 , Figs. 38-45. Scattergram plots of various metric measurements and indices in workers of the Pseudomyrmex ferrugineus group, "others" refers to all other species in the P. ferrugineus group. 129 queens + veneficus x mixtecus □ ferrugineus, flavicornis A janzeni ,dB £ooJ** <* 47 ' queens D 0.56 - ■+■ veneficus x mixtecus x a ° D ferrugineus. flavicornis * D A janzeni *< X X D ° dP a «. nigrocinctus , parttceps x D 5* 05 - & peperi D a Oj, a 0.48 - • + o C nn B D D 0.46 - • + + 4 ° B a a 0.44 - • • ♦ ♦ D ° 0.42 - •P" i * 0.4 - •• ♦♦.» 0 38 - 0.34 - 48 workers 0.42 - + D janzeni Mexican ferrugineus a G 04 - + 0 m 0.39 - 0.38 - D a 0.37 - a * D ° D 0.36 - + D a 0.35 - o 0.34 - 0.33 - a a a o a D o a 0.32 - a 0 31 - 0.3 - * * -i 1 1 r— — i 1 1 — 49 1.04 - queens +■ flavicornis a o * 1.02 - D ferrugineus t ♦ 1 - 0.98 - A janzeni a D a D o + + 0.96 - 0.94 - a a a o o □ <* ° a a J 0.92 - 0 9 - a D O D ♦ 0.88 - D 0.86 - 0 84 - a o ° o 0.82 - A 0B - 0.78 - A A* 0 76 - . - ■ 0 92 0 94 0 96 0 98 1 1.02 1.04 1 06 1.08 1.1 1.12 1. 50 workers + flavicornis a 0.59 - a ferrugineus D * 0.58 - * + 0.57 - 0.56 - °v o° D * + 0.55 - D U ca a + + * 0.54 - 0.53 - a D D + + 9 aj° ° o a 0 5 - % o 0.49 - oQ °Q 0.48 - a 0.47 - + 0.46 - a 0.45 - 51: + 0 53 - + * 0.52 - 0.51 - 0 5 - a * + + + 0.49 - 0.48 - 0 D D a 0 ♦ + 0.47 - 0.46 - 0.45 - D 1 B ° DO % o % a a + D 3° D a a a 0.44 - 0.43 - 0.42 - 0.41 - a workers a o a a 8 D D Iff a o ° D ° D 0 a 0 4 - 0.39 - + a flavicornis ferrugineus 0 0 a 52 0.84 0.62 0.B 0.78 0.76 - 0.74 0.72 0.7 - 0 66 - 066 0.64 0.62 0.6 • A* DD O a D *n <° u % "'"n *M 1°°*° • nn»" J9 P queens +■ spinicola X salanicus D ferrugineus complex A others 53 workers ^ ■*- gracilis 0.75 - X nigropilosus * w X X X u opaciceps 0.7 - X> " X A ♦ simulans reconditus 0.65 - »* A J ♦ 0.6 - 0.55 - ♦ t * *.+ % * 0.5 - 0.45 - a D # + * * + ♦ * + 0 4- Figs. 46-53. Scattergram plots of various metric measurements and indices in Pseudomyrmex workers and queens. 46-52. P. ferrugineus group; "others" refers to all other species in the P. ferrugineus group; "P. ferrugineus complex" refers to a complex of five species: ferrugineus, flavicornis, janzeni, mixtecus and veneficus; 53, P. gracilis group. 130 Journal of Hymenoptera Research KEY TO PSEUDOMYRMEX SPECIES ASSOCIATED WITH SWOLLEN-THORN ACACIAS (BASED ON WORKERS AND QUEENS) The following key includes all species of Pseudomyrmex which have been found inhabiting swollen- thorn acacias in Mexico, Central America, or Colombia. Pseudomyrmex ants can be distinguished from others by their possession of a distinct postpetiole (i.e. "waist" consists of two nodes), well developed sting, relatively large eyes (eye length more than one-third head length), and short antennal scapes (one half head width or less). In the key below, species of Pseudomyrmex which are believed to be obligate inhabitants of acacia are in bold print. These species are typically rather aggressive (but this is not true of P. subtilissimus or P. nigropilosus),wh\\e the remaining facultative inhabitants are timid, generalist, stem-nesting Pseudomyrmex which usually occupy swollen-thorn acacias only sporadically. Couplets 11-19 cover the P. ferrugineus group, the principal group of obligate acacia-ants and the focus of this study. Taxonomic comments on the other acacia-inhabiting species are presented in a later section of the paper (pp. 153- 162). Worker sizes exclude nanitic workers, i.e. the first-emerging miniature workers associated with colony-founding queens. 1 . Standing pilosity very sparse on the head, including the gula (underside), and on the mesosoma; 1,0, and 0-1 pairs of erect setae on the pronotum, mesonotum, and propodeum, respectively, of the worker 2 — Standing pilosity common to abundant on most parts of the body, including the gula and mesosoma; worker usually with more than 10 standing hairs visible in outline on the mesosoma dorsum, not arranged in isolated pairs 4 2. Very small, light brown species (worker and queen HW < 0.60), with elongate head (CI < 0.66) and low, dorsally flattened petiole (PLI < 0.76) (Nicaragua, Costa Rica) subtilissimus (Emery) — Larger species (worker and queen HW > 0.70). with broader head (CI > 0.70) and higher petiole ( PLI > 0.80) (Figs. 1,2) 3 3. Smaller species (worker and queen HW < 1.00), with posterodorsally angulate petiole (Fig. 2) (Mexico to Colombia) ita (Forel) — Larger species (worker and queen H W > 1 . 1 5 ), with posterodorsally rounded petiole ( Fig. 1 ) ( Mexico to Ecuador, Brazil) boopis (Roger) 4. Head with scattered, fine punctulae on a smooth, shiny background; punctulae on upper third of head separated by several times their diameters or more 5 — Head opaque to sublucid, more coarsely and densely punctulate, the punctulae subcontiguous on most parts of the head 6 5. Larger species (HW> 1.20), with broad head (CI 1.1 2) and abundant long pilosity (Fig. 3) (Mexico to Argentina, Brazil) kuenckeli (Emery) — Small species (HW < 0.72), with elongate head (CI 0.80) and shorter, sparser pilosity (Fig. 4) (Mexico) hesperius, sp.nov. 6. Eyes relatively large and elongate (e.g. Fig. 5), eye length more than one-half head length (worker and queen REL 0.52-0.65); pronotum laterally submarginate; outer surfaces of tibiae usually with standing pilosity (may be very short); larger species, worker HW > 1.20; palp formula 6,4 7 - Eyes smaller (Figs. 10- 19), usually less than one-half head length (worker and queen REL 0.38-0.50); pronotum laterally rounded; outer surfaces of tibiae without standing pilosity; medium-sized species, worker HW < 1 .28; palp formula 5,3or 4,3 {ferrugineus group) 1 I 7. Petiole long and slender, with a well developed anterior peduncle (worker and queen PLI 0.42-0.57) Volume 2, Number 1, 1993 131 (Figs. 5,6) 8 — Petiole less elongate, with a short anterior peduncle (PLI > 0.59) (Figs. 7-9, 53) 9 8. Head densely punctulate-coriarious, presenting a matte appearance: head and mesosoma black, with a contrastingly pale orange petiole, postpetiole, and gaster; petiole very slender, worker PLI 0.42-0.47 (Figs. 5, 53) (southern Mexico, Guatemala) opaciceps, sp. nov. — Head densely punctulate but retaining a subopaque to sublucid (not matte) appearance; color variable but without the preceding pattern in Mexico or Guatemala; petiole usually less slender, worker PLI 0.46-0.57 (Figs. 6, 53) (throughout the Neotropics) gracilis (Fabricius) 9. Larger species (worker HW 1 .47- 1 .54, queen HW 1 .66), with broad head (worker CI 1 .00- 1 .02, queen CI 0.92) (Nicaragua) reconditus, sp. nov. — Smaller species (worker HW 1 .2 1 - 1 .4 1 , queen HW 1.15-1.36); head more elongate ( worker CI 0.84- 0.90, queen CI 0.77-0.80) 10 10. Standing pilosity short, pale and inconspicuous (Fig. 9); pronotum sharply margined laterally; petiole longer, worker PLI 0.61-0.66, queen PLI 0.63-0.68; color black (Panama) simulans Kempf — Standing pilosity long and conspicuous, with long curved black setae arising from the propodeum and petiole (Fig. 7); pronotum with blunter lateral margination; petiole short and high, worker PLI 0.69- 0.77, queen PLI 0.68-0.75; color variable, usually pale or bicolored (Mexico to Costa Rica) nigropilosus (Emery) 1 1. Median clypeal lobe of worker concave, with sharp lateral angles or teeth (Figs. 10, 1 1); legs long in relation to body size (Figs. 30. 3 1 ); larger species (worker HW > 0.92, worker LHT > 0.88, queen HL > 1.40, queen LHT > 1.05); frontal carinae closely contiguous, worker FCI2 0.24-0.42 (Fig. 32); propodeum punctulate to coriarious-imbricate, posterolateral portions sublucid with little or no overlying, coarse, rugulo-punctate sculpture 12 — Median clypeal lobe of worker laterally rounded or subangulate (without sharp angles or teeth) (Figs. 12-19); legs shorter in relation to body size (Figs. 30, 3 1 ); size variable but if as large as the preceding ( worker H W > 0.92, etc. ) then frontal carinae relatively well separated, worker FCI2 > 0.43 (Fig. 32), and posterolateral portions of propodeum opaque to subopaque, overlain by coarse (although often weak and ill-defined) rugulo-punctate sculpture 13 12. Larger species (worker HW> 1.09, queen HW> 1. 20); head broader, its posterior margin straight and rounding rather sharply into the sides (Figs. 10, 34); median clypeal lobe of worker longer and narrower (Fig. 33 ); worker with a conspicuous, pit-like impression on midline of head, anterior to the median ocellus; palp formula 4,3 (Panama) satankus (Wheeler) — Smaller species (worker HW 0.94-1 . 15, queen HW 0.94 -1.14), with head a little less broad and its posterior margin rounding more gently into the sides (Figs. 10, 34); median clypeal lobe of worker notably shorter and broader (Fig. 33); worker usually lacking a pit-like impression on mid-line of head; palp formula almost invariably 5,3, rarely 5p4,3 (Honduras to Colombia spinicola (Emery) 13. Smaller species (worker HW 0.74-0.90, queen HW 0.76-0.85); head, propodeum, and petiole more elongate, for a given head width (Figs. 36-38) 14 ■ Larger species (worker HW 0.85-1.21, queen HW 0.84- 1 . 19); head, propodeum, and petiole shorter, for a given head width (Figs. 36-38) 16 14. Petiole and postpetiole very broad (worker PWI 0.63-0.75, worker PWI3 0.33-0.46, worker PPWI 1 .41-1.83; queen PWI2 0.69-0.78) (Figs. 40, 41), the petiolar node with conspicuous posterolateral angles, in dorsal view (Fig. 24); head very finely and densely punctulate-coriarious, presenting a matte (opaque) appearance; palp formula 4,3 (Mexico to Nicaragua) peperi (Forel) • Petiole and postpetiole relatively narrow (worker PWI 0.49-0.61, worker PWI3 0.50-0.61, worker PPWI 1 .03- 1 .30; queen PWI2 0.57-0.63 ), the petiolar node without conspicuous posterolateral angles 132 Journal of Hymenoptera Research (Figs. 22,23); head densely punctulate, sublucid to subopaque, but without a matte appearance; palp formula 5,3 15 15. Workers and queens light orange-brown, with a fuscous patch on anterior third of abdominal tergite IV (first gastric tergite); eyes relatively short (worker EL/LHT 0.56-0.61, queen REL2 0.58-0.66) (Figs. 13, 42, 43); queen head less elongate (queen CI 0.67-0.72) (Guatemala to Costa Rica) nigrocinctus (Emery) Workers and queens entirely dark brown; eyes longer (worker EL/LHT 0.59-0.64, queen REL2 0.69- 0.70) (Figs. 14, 42, 43); queen head more elongate (CI 0.61, in the two known specimens) (Costa Rica) particeps, sp. nov. 16. Small species (worker HW 0.85-0.95, queen HW 0.84-0.96) with head, gaster, and at least part of mesosoma very dark brown to black; body pubescence dense, decumbent to suberect, and conspicu- ous, especially on the petiolar node (Fig. 28); standing pilosity often (not always) sparse; head weakly shining (western Mexico) veneficus (Wheeler) — Body pubescence dense but predominantly appressed, petiolar node without conspicuous suberect pubescence; usually larger (worker HW 0.89-1.21. queen HW 0.96-1.19) with more conspicuous standing pilosity; color and head sculpture variable 17 17. Head and gaster (typically also mesosoma) very dark brown to black; head densely punctulate and opaque 18 — Body lighter in color: light orange-brown to medium brown, rarely dark brown; head at least weakly sublucid between ocelli and upper margin of the compound eye 19 18. Smaller species, worker HW 0.89-1.03, queen HW 0.96-1.01; petiole relatively longer and higher (Figs. 44-47) (southern Mexico) mixtecus, sp. nov. — Larger species, worker HW 0.99- 1.21, queen HW > 1.10; petiole relatively shorter and lower (Figs. 44-47) (Guatemala to Costa Rica) .flavicornis (F. Smith) 19. Head and mesosoma light orange-brown, the gaster similar or slightly darker; underside of head (gula) with conspicuous suberect pubescence (Fig. 19); profile of worker mesosoma as in Fig. 29; smaller species (worker HW 0.93-1.03, queen HW 0.96-1.00) with shorter, higher petiole (Figs. 46-49) (western Mexico) Janzeni, sp. nov. - Gaster (and usually head) medium to dark brown, mesosoma variable; gular pubescence usually more appressed and inconspicuous; in profile worker mesosoma usually with basal face rounding more gradually into declivitous face (Fig. 27); size variable but larger on average (worker HW 0.92- 1 . 1 5,queen HW 0.92- 1.12), with longer and lower petiole ( Figs. 46-49) (eastern and southern Mexico to Honduras) ferrugineus (F. Smith) KEY TO MALES OF THE OBLIGATE ACACIA-ANTS, PSEUDOMYRMEX FERRUGINEUS GROUP Although isolated acacia-ant males are unlikely to be encountered, the following key is offered as a supplement for determination of species in the P. ferrugineus group. It can be used to confirm worker- or queen-based identifications, but some couplets require examination of the male genitalia. 1 . Posterior margin of subgenital plate (sternite IX) with a shallow (less than semicircular) concavity (Fig. 54); scape short, SI2 0.33-0.43, SL/HL 0.21 2 - Posterior margin of subgenital plate (sternite IX) with a deep, semicircular concavity (Fig. 55); scape longer, SI2 0.43-0.56, SL/HL 0.22 3 2. Paramere, in lateral view, with a slender finger-like mediodorsal lobe and angulate posteroventral corner (Fig. 57) particeps - Paramere, in lateral view, with a stubbier mediodorsal lobe and more gently rounded posteroventral Volume 2, Number 1, 1993 133 corner (Fig. 56) nigrocinctus Scape and compound eye longer, relative to HW (SI 0.29-0.35; REL2 0.56-0.62 (n=6)); head narrower, CI 0.82-0.94, HW 0.81-0.95; lateral view ofparamere as in Figs. 58a, 58b peperi Scape and compound eye shorter (SI 0.22-0.30, REL2 0.49-0.58 ); head broader, CI 0.94 and/or H W 0.96; lateral view ofparamere not as in Figs. 58a, 58b 4 Paramere, in lateral view, with posterodorsal corner well separated from mediodorsal lobe (Figs. 59- 60) 5 Paramere, in lateral view, with posterodorsal corner bent upward and enclosing a space between itself and the mediodorsal lobe which is subequal to the area of the latter (Figs. 61-65) 6 Lateral view of paramere as in Figs. 59a and 59b: mediodorsal lobe relatively broad and partly enclosing a space between itself and the posterodorsal corner; larger species, HW 1.06-1.09 (n=5) satanicus Paramere typically as in Fig. 60a, with mediodorsal lobe more slender and more distant from posterodorsal corner (Fig. 60b depicts a less typical male, from Colombia); smaller species, H W 0.92- 1.05 (n=12) spinicola Mediodorsal lobe of paramere stout, directed more or less dorsally (Figs. 61, 62) 7 Mediodorsal lobe ofparamere more slender and directed posterodorsally (Figs. 63-65) 8 Body pubescence dense and conspicuous, suberect on dorsum of head, propodeum and petiole; smaller species, HW 0.79-0.88 (n=7) veneficus Body pubescence less dense and less conspicuous, predominantly appressed or decumbent on the propodeum and petiole; larger species, HW 0.88-0.97 (n=6) mixtecus Smaller species, HW 0.93-0.96 (n=6) janzeni Larger species, HW 0.99-1.19 (n=22) ferrugineus and flavicornis PSEUDOMYRMEX FERRUGINEUS GROUP Introduction Worker, diagnosis. — Medium sized species ( H W 0.74- 1 .26, HL 0.86- 1 .42); head varying from mod- erately elongate to rather broad (CI 0.75-0.97), with relatively short eyes (REL 0.39-0.50, REL2 0.45- 0.62) (Figs. 10-19). Masticatory margin of man- dible with 6, rarely 7. teeth. MD8/MD9 0.70; mesial tooth on basal margin notably closer to apicobasal angle than to proximal tooth, MD4/ MD5 0.74. Palp formula 5,3, reduced to 4,3 in two species. Anterior margin of median clypeal lobe somewhat blunt-edged, in dorsal view convex, straight or concave, laterally rounded or with sharp angles. Frontal carinae separated by about basal scape width in most species but more closely con- tiguous in two (FCI 0.03-0. 1 0, FCI2 0.24-0.75, ASI 0.52-0.73), fusing anterolaterally with antennal sclerites. Funicular segments II and III about as broad as long (FLI 1 .46-2.45). Profemur slender (FI 0.35-0.41 ). Pronotum laterally rounded. Metanotal groove well marked (MPI 0.04-0.09). Basal and declivitous faces of propodeum moderately well differentiated and subequal in length (PDI 0.94- 1.30), in profile the juncture between the two subangulate or gently rounded (Figs. 20-29). Peti- ole relatively long (PL/HL 0.44-0. 63), always much longer than high or wide (PLI 0.47-0.7 1 , PWI 0.46- 0.75), small anteroventral tooth present; in two species anterior peduncle of petiole weakly differ- entiated and posterolateral corners of petiolar node not expanded (these are presumably the plesiomorphic conditions in the group), in other species petiole with distinct anterior peduncle and with expanded, (sub)angulate posterolateral cor- ners. Postpetiole broader than long (PPWI 1.03- 1.85), with small anteroventral tooth. Body sculp- ture varying from densely punctulate or punctulate- coriarious to coriarious-imbricate, the integument sublucid to opaque; dorsum of head never with extensive smooth, shiny interspaces (punctulae usually separated by their diameters or less); propodeum of some species overlain by a coarser but weak rugulo-punctate sculpture. Standing pi- losity common, present on the scapes, head, entire mesosoma dorsum (10 or more standing hairs vis- ible in profile), petiole, postpetiole and gaster, 134 Journal of Hymenoptera Research 54 57 58b 60a 60b 63a 61b 63b 62 mm Figs. 54-66. Pseudomyrmexferrugineus group, male terminalia. Figs. 54-55: sternite IX; Figs. 56-65: left paramere. lateral view, caudal end to right; Fig. 66: left paramere, mesial view. 54, P. particeps (Rincon, Costa Rica); 55, P. mixtecus (near Tehuantepec, Mexico); 56, P. nigrocinctus (lOmi. NW Liberia, Costa Rica); 57, P. particeps ( Rincon, Costa Rica); 58, P. peperi (58a: 3km ENE Chiapa de Corzo, Mexico; 58b: Nueva Ocotepeque, Honduras I; 59, P. satanicus (59a: 3mi. SW Gatun Dam, Panama; 59b: Marajal, Panama); 60, P. spinicola (60a: Madden Dam, Panama; 60b: Aracataca, Colombia); 6 1 , P. mixtecus (61a: 57.8mi. S Chilpancingo, Mexico; 61b: near Tehuantepec. Mexico); 62, P. veneficus (5km E Chamela, Mexico); 63. P.flavicornis (63a: Rio Oro, Costa Rica; 63b: 3.6mi. W Choluteca, Honduras); 64, P.janzeni (64a: 60mi. SE Acaponeta, Mexico; 64b: 4mi. E San Bias. Mexico); 65, P. ferrugineus (65a: Escuintla-Cd. Guatemala, Guatemala; 65b: 10.8mi S Pichucalco, Mexico); 66, P. ferrugineus (10.8mi S Pichucalco, Mexico). Volume 2, Number 1, 1993 135 absent from the extensor faces of tibiae. Appressed pubescence dense on most of body, including head and abdominal tergite IV. Color varying from light yellow- or orange-brown to black. Queen diagnosis. — Similar to worker except for caste-specific differences. Larger in size ( HW 0.76- 1 .36. HL 1 .05- 1.81). head more elongate (CI 0.60- 0.80). Ocular indices differing slightly: REL 0.38- 0.48. REL2 0.51-0.70. Median clypeal lobe nar- rower and more protruding, anterior margin convex or straight, laterally rounded or subangulate. Peti- ole and postpetiole generally more slender (PL/HL 0.57-0.72, PLI 0.43-0.63, PWI 0.47-0.67, PPWI 1.06-1.50). Forewing with 2 cubital cells. Male, diagnosis. — Head varying from longer than broad to slightly broader than long (CI 0.82- 1.04 in a sample of 70 males belonging to all species); compound eye large, prominent (REL2 0.49-0.62 ). Mandibles with 8+ teeth or denticles on masticatory margin. Palp formula as in females, but somewhat more variable (males with 5p4,3 commoner than in workers or queens). Surface of median clypeal lobe convex, its anterior margin subtriangular in shape (dorsal view) with sides converging medially to a rounded point. Petiole and postpetiole more slender than in workers (PLI 0.40-0.55. PWI 0.35-0.51) and simpler in shape. Posterolateral corners of sternites IV-VIII not nota- bly protruding ventrally. Subgenital plate (sternite IX) with a conspicuous posteromedial concavity (Figs. 54, 55). Posterior margin of pygidium (terg- ite VIII) convex, directed posteroventrally. Paramere with several characteristic features: a finger-like, posterodorsally directed mediodorsal lobe; angulate or expanded posterodorsal extrem- ity; and mesial dorsoventral ridge which joins the mediodorsal lobe posteriorly. Aedeagus with ex- panded posterodorsal corner, a medial protrusion on the posterior margin, numerous small teeth (15+) on the posterior margin, and on the outer face a raised ridge curving posterodorsally from a basal origin. Comments. — Workers and queens of the P. ferrugineus group can be distinguished from all other Pseudomyrmex by their possession of the following combination of traits: mandibles with 6- 7 teeth; palp formula 5,3 or 4,3; standing pilosity common on mesosoma dorsum but absent from external faces of tibiae; worker metanotal groove conspicuously impressed; and head densely punctulate, sublucid to opaque. The relatively short eyes (worker REL 0.50, queen REL 0.48) and slender petiole (worker PLI 0.7 1 , queen PLI 0.63) are also characteristic. Among the eight other major species groups of Pseudomyrmex (diagnosed in Ward. 1989 (only the P. viduits and P. oculatus groups have workers and queens approach- ing these conditions. Those of the P. vidmts group have a shinier head, a shorter and more robust petiole (worker PLI > 0.70, worker PWI > 0.70). and standing pilosity on the tibiae (reduced in one species ), while workers and queens of the P. oculatus group have a palp formula of 6,3 (reduced to 5,3 only in smallest species with worker and queen H W < 0.67). tectiform and sharp-edged median clypeal lobe with a broadly convex margin (dorsal view), elongate eyes ( worker REL 0.48-0.6 1 , worker REL2 0.62-0.86, queen REL0.43-0.57, queen REL2 0.68- 0.89), and short petiole (worker PLI 0.67-1.06, queen PLI 0.57-0.94). Among taxonomically iso- lated species not belonging to one of the major species groups. P.fervidus (F. Smith ) bears perhaps the closest phenetic resemblance to the P. ferrugineus group, but its workers and queens can be distinguished by their shinier and less densely punctulate head, shorter petiole (worker PLI 0.71- 0.76, worker PL/HL 0.4 1-0.44 (n=9): queen PLI 0.65, queen PL/HL 0.49), and standing pilosity on the outer faces of the tibiae. In addition the queens of P. fen'idus have a distinctive, pointed median clypeal lobe not seen in P. ferrugineus group queens. Males of the Pseudomyrmex ferrugineus group can be characterized by their palp formula, medi- ally subangulate clypeal lobe, emarginate subgenital plate, configuration of the paramere, and shape of the aedaegus. They are approached most closely in this combination of traits by males of P. haytianus (Forel) and two undescribed Central American species (P. sp. PSW-02 and P. sp. PSW-54) al- though, curiously, the workers and queens of those species do not bear a close resemblance to those of the P. ferrugineus group. All species in the P. ferrugineus group are obligate inhabitants of Central American swollen- thorn acacias, a biological trait not characterizing any other species group of Pseudomyrmex. al- 136 Journal of Hymenoptera Research though a few species in the otherwise quite differ- ent P. gracilis group and one species in the P. subtilissimus group have independently developed an obligate association with the acacias. Distribution. — Members of the P. ferrugineus group are found from eastern (San Luis Potosi, Tamaulipas) and western (Sinaloa) Mexico south through Central America to northern Colombia (Fig. 67). Although no single species spans the entire range of the group, their collective distribu- tion is virtually identical to that of the swollen- thorn acacias (compare Fig. 67 with Janzen 1974:3). Synonymic List of Species P. ferrugineus (F. Smith 1877) Mexico to Hondu- ras = P. fulvescens (Emery 1890) (Ward 1989) = P. canescens (Wasmann 1915) (Ward 1989) = P. wasmanni (Wheeler 1921) (replacement name for canescens) = P. bequaerti (Wheeler 1942) (Ward 1989) = P. saffordi (Wheeler 1942) (Ward 1989) = P. vesanus (Wheeler 1942) (Ward 1989) = P. bequaerti (Enzmann 1945) (Brown 1949) = P. honduranus (Enzmann 1945) (Ward 1989) P.flavicornis (F.Smith 1877) Guatemala to Costa Rica = P. belti (Emery 1890) (Ward 1989) = P. obnubilus (Menozzi 1927a) (Ward 1989) = P.fellosus (Wheeler 1942) (Ward 1989) P. janzeni Ward, sp. nov. Mexico P. mixtecus Ward, sp. nov. Mexico P. nigrocinctus (Emery 1890) Guatemala to Costa Rica = P. alfari (Forel 1906) syn. nov. = P. bicinctus (Santschi 1922) syn. nov. = P. peltatus (Menozzi 1927) syn. nov. P. particeps Ward, sp. nov. Costa Rica P. peperi (Forel 1913) Mexico to Nicaragua = P. convarians (Forel 1913) (Ward 1989) = P. saffordi (Enzmann 1945) (Ward 1989) P. spinicola (Emery 1890) Honduras to Colombia = P. atrox (Forel 1912) syn. nov. = P. gaigei (Forel 1914) syn. nov. = P. infernalis (Wheeler 1942) syn. nov. = P. scelerosus (Wheeler 1942) syn. nov. = P. infernalis (Enzmann 1945) (Brown 1949) = P. scelerosus (Enzmann 1945) (Brown 1949) P. satanicus (Wheeler 1942) Panama P. veneficus (Wheeler 1942) Mexico = P. venificus (Enzmann 1945) (Brown 1949) SPECIES ACCOUNTS Pseudomyrmex ferrugineus (F. Smith 1877) (Figs. 18.27,65,66,70) Pseudomyrma ferruginea F. Smith 1877:64. Lec- totype worker, Mexico (BMNH) [Examined]. Pseudomyrma belti racefulvescensEmery 1890:64. Lectotype worker, Guatemala ( Beccari ) ( MCS N ) [Examined] [Synonymy by Ward 1989:437; see also Janzen 1967b:391]. Pseudomyrma canescens Wasmann 1915:321. Syntype workers, Tampico.Mexico(Brakhoven) (MCSN, MCZC) [Examined] [Synonymy by Ward 1989:437]. Pseudomyrma wasmanni Wheeler 1921:92. Re- placement name, now unnecessary, for P. canescens Wasmann 1915 (necF. Smith 1877). Pseudomyrma belti subsp. bequaerti Wheeler 1942:164. Lectotype worker, Puerto Castilla, Honduras (J. Bequaert) (MCZC) [Examined] [Synonymy by Ward 1989:437]. Pseudomyrma belti subsp. saffordi Wheeler 1942:162. Lectotype worker, Chicoasen, Chiapas, Mexico (G. N. Collins) (MCZC) [Ex- amined] [Synonymy by Ward 1989:437]. Pseudomyrma belti subsp. vesana Wheeler 1942:163. Holotype (unique syntype) worker, Cordoba, Mexico (F. Knab) (MCZC) [Exam- ined] [Synonymy by Ward 1989:437]. Pseudomyrma belti subsp. bequaerti Enzmann 1945:80. Syntype workers, Puerto Castilla, Honduras (J. Bequaert) (MCZC) [Examined] [Objective synonym of P. belti bequaerti Wheeler; Brown 1949:42]. Pseudomyrma kuenckeli var. hondurana Enzmann 1945:87. Lectotype worker, Honduras (Bates) (MCZC) [Examined] [Synonymy by Ward 1989:437]. Pseudomyrmex ferruginea [sic] (F. Smith); Janzen 1966:252. Pseudomyrmex ferrugineus (F. Smith); Kempf Volume 2, Number 1, 1993 137 C Sf B E c 2 = j 2 H -c S- 2 a. en o ~^i —2 -^ — ™ ^ aa A £x a E a ~ S 3 3 "Si -C -C -Xj -c -c __.^ - ! ~ C- ^ " X 4 ,2 XX C S > ^ .£ 3 d u 0» 6 5 c — cu OJ G cl, 2 B £ ?. o ,4j f"T dJ ~ £ o -a > $■ 2 §3 ^ -£ >* C ^c :J OJ U -c OJ a. •— ' ? *. 138 Journal of Hymenoptera Research 1972:218. Worker measurements (n = 69 ). — HL 0.99- 1.33, HW 0.92-1.15. MFC 0.054-0.108, CI 0.81-0.94, REL 0.42-0.48, REL2 0.48-0.54, OOI 1.39-3.16. VI 0.60-0.78, FCI 0.054-0.101, SI 0.41-0.46, SI2 0.79-0.9 1 . NI 0.6 1 -0.72, PLI 0.54-0.69, PWI 0.56- 0.73, PPWI 1.34-1.70. Worker diagnosis. — Medium-sized species ( H W > 0.91; LHT 0.75-1.06) with broad head (CI > 0.80); anterior margin of median clypeal lobe straight or weakly concave, rounded laterally; palp formula 5,3; frontal carinae well separated (FCI > 0.05) and median lobe of antennal sclerite not strongly ex- posed (FCI2 0.45-0.69); mesosomal profile typi- cally as in Fig. 27, with mesonotum notably in- clined and with basal face of propodeum rounding gradually into declivitous face, but deviations from this pattern occur; petiole relatively short, high and wide (see relevant metrics: PLI. PWI). with a dis- tinct anterior peduncle (PWI3 0.36-0.50); postero- lateral angles of petiole moderately developed but not as pronounced as in P. peperi (compare Figs. 24 and 27); postpetiole broad. Head densely punctulate, predominantly opaque or subopaque but at least weakly shining on upper third of head between ocelli and compound eye; mesosoma punctulate to punctulate-coriarious. subopaque to sublucid; pos- terior portions of propodeum opaque to subopaque and usually overlain by larger but weak, irregular punctures or rugulae. Petiole, postpetiole and gaster with fine piligerous punctures, sublucid. Standing pilosity common: pubescence dense but fine and appressed on most surfaces. Color variable, from light reddish- or yellowish-brown to very dark brown, gaster (and usually head) somewhat darker than the mesosoma; mandibles, scapes, fronto- clypeal complex, and apices of legs usually lighter. Comments. — Workers and queens of P. ferrugineus can be recognized by features of head morphology (laterally rounded median clypeal lobe, well separated frontal carinae and correspondingly limited exposure of the median lobes of the anten- nal sclerites, and moderately broad worker head; see Fig. 18), head sculpture (densely punctulate and (sub)opaque. but weakly shining on upper third of head between the ocelli and compound eye), and coloration (variably brown, not black or orange- brown). This species is most likely to be confused with the allopatric P.janzeni and the partly sympa- tic P.flavicornis. See under those species for more specific discussion. Distribution and biology. — P. ferrugineus is distributed from eastern and southern Mexico to El Salvador and Honduras (Fig. 70). It is a common species and colonies have been recorded from all swollen-thom acacia species growing within its range, i.e. Acacia chiapensis, A. collinsii, A. cookii, A. cornigera, A. gentlei, A. globulifera. A. hindsii, A. janzenii, A. mayana and A. sphaerocephala. P. ferrugineus is usually monogynous ( Janzen 1 967b, 1973) but a few alcohol nest series from Guate- mala, belonging to apparently mature colonies (as judged by the presence of alates), contained more than one dealate queen. Janzen (1966, 1967b) conducted a massive experimental study of the interaction between P. ferrugineus and Acacia cornigera in Mexico, and the results of these ex- periments, together with copious additional obser- vations by Janzen, showed conclusively that the ants protect the acacia from herbivores and compet- ing plants (especially vines). P. ferrugineus was also the subject of a study on kinship and nestmate recognition among workers ( Mintzer 1 982; Mintzer et al. 1985) which demonstrated a worker-based and probably inherited component to colony odor. Statements about the biology of "P. ferruginea" from regions south of El Salvador and Honduras (e.g. Janzen 1983) refer to a different species, P. spinicola. Material examined (AMNH. BMNH. CASC, CHAH, CISC, CUIC, INHS, LACM, MCSN, MCZC, MHNG, MNHN, MZSP. NHMV, PSWC, SEMC, UCDC, USNM, WPMC).— BELIZE £?//;:<*: 2.2miW Belize, rd.to Chetumal (D.H.Janzen); 3.8mi NW Belize, rd.to Chetumal (D.H.Janzen); 4.9mi SW Belize, rd.to Cayo (D.H.Janzen); Belize (Baker; c.u.); Manatee [River] (J.D.Johnson; c.u.); nr. Belize (N.L.H.Krauss); Cayo: 36.1 mi SW Belize (D.H.Janzen); 36. lmi [S]W Belize (U.Kansas Mex.Exped.); El Cayo [=San Ignacio] (N.L.H.Krauss); Pine Mtn. Ridge, Mecal R., 415m (G.D.Alpert); San Ignacio (S.E.SchoenigkCorocfl/: 1 3. 5miSSta. Elena (Lou- isville) (D.H.Janzen); 15mi S Sta. Elena (Louis- ville) (D.H.Janzen); Orange Walk: 5mi SE Orange Volume 2, Number 1, 1993 139 Walk, rd.to Belize (D.H.Janzen); Toledo: Punta Gorda (H.Broomfield). EL SALVADOR Chalatenango: 4.7mi NW La Palma. 880m (D.H.Janzen); 5.5mi SE La Palma, 1130m (D.H.Janzen). GUATEMALA Alta Verapaz: San Joaquin, nr. San Cristobal Verapaz, 1 080m ( D.H.Janzen ); Trece Aguas (Schwarz & Barber): Chimaltenango: Yepocapa (H.T.Dalmat): Coatepeque: 2mi W Coatepeque (D.H.Janzen); EI Progreso: 4.9mi SW Sanarate, 780m (D.H.Janzen); Escuintla: 1.7mi S Escuintla, 370m [on CA-2] (D.H.Janzen); 12.6mi NE Escuintla, id. to Cd. Guatemala, 1120m (D.H.Janzen); 15km E Escuintla [on CA-9] (D.H.Janzen); 3mi N Escuintla [on CA-9] (D.H.Janzen); 3mi S Escuintla [on CA-9] (D.H.Janzen); 43km S Cd. Guatemala [=15km E Escuintla] (D.H.Janzen); 6.8mi S Escuintla, 280m [on CA-2] (D.H.Janzen); 8.3mi N Escuintla [on CA-9] (D.H.Janzen); 9.2mi N Escuintla, 900m [on CA-9] (D.H.Janzen); Escuintla (W.M.Wheeler); Pantaleon (Champion); Guatemala: 16.2mi NE Cd.Guatemala ( D.H.Janzen); 1 9km S Cd.Guatemala [on CA-9] (D.H.Janzen); 20mi SE Cd.Guatemala, 1060m [on CA-1] (D.H.Janzen); 6.2mi NE Cd.Guatemala, 700m (D.H.Janzen); 7.9mi S Cd. Guatemala, 1 360m [on CA-9] (D.H.Janzen): 8. lmi NE Cd. Guatemala, 850m (D.H.Janzen); Cd. Gua- temala (Champion); Cd. Guatemala, 980m (D.H.Janzen); Escuintla-Cd.Guatemala [=19km S Cd. Guatemala] (D.H.Janzen); Huehuetenango: 12.4mi SE Mex. border at Cd. Cuauhtemoc (D.H.Janzen); 12.5mi SE Mex.border at Cd. Cuauhtemoc (D.H.Janzen); 37.6mi NW Huehuetenango, 900m (D.H.Janzen); 7. lmi SE Mex.borderatCd. Cuauhtemoc (D.H.Janzen);9.3mi SE Mex.border at Cd. Cuauhtemoc (D.H.Janzen); Izabal: 1.1 mi NE Quirigua, 120m (D.H.Janzen); 2. lmi SW Morales, 50m (D.H.Janzen); Lagolzabal, lkm NE El Estor [= 1.5km NE El Estor] (D.H.Janzen); Los Amates (Kellerman); Murciellago (D.H.Janzen); Quirigua (W.M.Wheeler); Jutiapa: 6.7mi N San Cristobal, 280m (D.H.Janzen); 6.9mi N San Cristobal, 290m (D.H.Janzen); 9miSW Jutiapa, 950m (D.H.Janzen); Peten: 70km NW Tikal (W.R.Tschinkel); Tikal (T.H.Hubbell; N.L.H.Krauss; W.R.Tschinkel); Quezaltenango: 7.2mi NE San Felipe, on Retalhuleu-QuezaltenangoRd. (D.H.Janzen); 7. 5mi NE San Felipe, on Retalhuleu-Quezaltenango Rd. (D.H.Janzen); Retalhuleu: 1.3mi E Champerico (D.H.Janzen); 2mi NE Champerico (D.H.Janzen); 5mi W Retalhuleu ( D.H.Janzen); 5mi W Retalhuleu, Hwy. CA-2, at Rio Nil (D.H.Janzen); Champerico (Baker; F.Knab); Puenta Samala, 3.8mi NE San Felipe (D.H.Janzen); Retalhuleu (Slott); SantaRosa: 25mi SE Escuintla, 200m [on CA-2] ( D.H.Janzen); Solola: "Pacific slope", 3000ft. (c.u.); Suchitepequez: Patulul (W.M.Wheeler); Zacapa: lOmi SW El Lobo, 170m [on CA-9] [=9.2mi NE Piedras de Afilar] (D.H.Janzen); 2.6mi SW El Lobo, 100m [on CA-9] [=16.6mi NE Piedras de Afilar] (D.H.Janzen); 8. lmi SWLos Amates, 160m [on CA-9] [=8.0mi NE El Lobo] (D.H.Janzen); 8.2mi NE Piedras de Afilar, 160m [on CA-9] [ = 12.2mi NE Rio Hondo] (D.H.Janzen); dept. unknown : "Guatemala" ( Beccari ); Concepcion, 1400ft. (C.N.Ainslie); Mimosa, "Cocepcion" [Concepcion] (C.N.Ainslie). HONDURAS Atidntida: Tela (quarantine New Orleans, U.S.A.) (T.J.Baker); Colon: Puerto Castilla (J.Bequaert); Comayagua: "Comayaena" (S. Passoa); 1 1.7miS San Antonio, 830m (D.H.Janzen); 1 5.7mi N Siguatepeque, 530m (D.H.Janzen); Minas de Oro (J.B.Edwards); Copan: 10.4mi S Sta. Rosa de Copan, 980m (D.H.Janzen); 1 1 .9mi S Sta. Rosa de Copan, 1130m (D.H.Janzen); 17.3mi N Sta. RosadeCopan,780m(D.H.Janzen); Cortes: 24.6mi SW San Pedro Sula, 240m (D.H.Janzen); 6.8mi S San Pedro Sula. 480m [=20.9mi SW Quimistan] (D.H.Janzen); San Pedro Sula (S.C.Bruner; W.M.Mann); Ocotepeque: 4.4mi E [Nueva] Ocotepeque, 1 3 10m (D.H.Janzen); Santa Barbara: 7.3mi E Quimistan (D.H.Janzen); 13.7mi SW Quimistan, 320m (D.H.Janzen); Yoro: Coyoles, W of Olanchito (Echternacht); dept.unknown: "Hon- duras" (Bates). MEXICO Camp.: 0.1 mi STenabo( D.H.Janzen); 0.8mi E Campeche (D.H.Janzen); 10.6mi E Campeche (D.H.Janzen) ; 20mi E Campeche, Hwy. 180(D.H.Janzen);29miE&12miS Campeche ( Ruinas Edzna)(D.H.Janzen); 48mi NE Puerto Real (Isla Aguada), Hwy. 180 (D.H.Janzen); Ruinas Edzna (U.Kansas Mex.Exped.); Chis.: 10 mi NE [NW?] Tapachula [on Hwy. 200?] (D.H.Janzen); 140 Journal of Hymenoptera Research 10.8mi S Pichucalco (D.H.Janzen); 11km SE Pichucalco, 400m (P.S.Ward); llmi E Arriaga (D.H.Janzen); 1km WSW Palenque, 80m (P.S.Ward); 26km E Cintalpa (W.MacKay); 2mi S Pichucalco (D.H.Janzen); 32mi W [San] Cristobal de las Casas, Hwy.190 (D.H.Janzen); 3km ENE Chiapa de Corzo, 500m (P.S.Ward); 3mi N Soyalo [on Hwy.195] (D.H.Janzen); 4mi NW Ocosingo (R.C.Bechtel & E.I.Schlinger; R.F.Smith); 4mi S SimojoveKR.C.Bechtel & E.I.Schlinger; E.I.Schlinger); 56.9mi NE [NW?] Tapachula [on Hwy.200?] (D.H.Janzen); 5mi SE Tapilula [on Hwy.195] (D.H.Janzen); 6.9mi N Tapilula (D.H.Janzen); 7mi SW Teapa [on Hwy.195] (D.H.Janzen); 8.5mi S La Trinitaria, 1160m (U.Kansas Mex.Exped.); 8.5mi S La Trinitaria, Hwy.190 (D.H.Janzen); 8mi W Las Cruces, Hwy.190, 660m (D.H.Janzen); 96km S Tuxtla Gutierrez, 732m (D.E. & J.A.Breedlove); Acapetahua Las Bugamvillas (F.Diaz); Arriaga (D.H.Janzen); Cd. Cuauhtemoc (D.H.Janzen); Chicoasen (G.N.Collins); El Real (Goodnight & Stannard); Ixtacomitan (R.Andrews); Llano Grande (G.N.Collins); Palenque (c.u.); Pichucalco (G.N.Collins); Rio Huixtla, Huixtla (J.G.Pereira); Ruinas Palenque (E.M.Fisher); San Sebastian [near Tuxtla Gutierrez; see Safford 1922:393] (G.N.Collins); Santo Domingo, 15mi SE [SW?] Simojovel (R.F.Smith); Tapilula (D.H.Janzen); Tonala, 40m (D.H.Janzen); Tonola [prob.=Tonala] (A.Petrunkewitch); Tuxtla Gutierrez (N.L.H.Krauss; W.P.Stoutamize); Yaxoquintela (J.E.Rawlins); Yerba Santa (G.N.Collins); Gro. :10mi NE Acapulco (D.H.Janzen); 15.8mi S Chilpancingo (D.H.Janzen); 18mi S Chilpancingo (F.D.Parker;F.D.Parker & L.A.Stange); 25.4mi S Chilpancingo (D.H.Janzen); 55mi N Acapulco, Hwy.95 (Cornell Univ. Mex. Field Party; c.u.); 57.8mi S Chilpancingo (D.H.Janzen); 59.9mi N Acapulco (D.H.Janzen); 62.4mi N Acapulco (D.H.Janzen); 74km N Acapulco (W.MacKay); Acapulco (L.J.Lipovsky); Revolcadero (N.L.H.Krauss); San Geronimo de Juarez (W.von Hagen); Hgo.: 2km W Orizatlan, 245m (W. Mac Kay);Mo/\:15miSCuernavaca(E.S. Ross; W.S.Ross); Cuernavaca (W.M.Wheeler); Oax.: 1 1 .4- 1 7.0mi W Tehuantepec (D.H.Janzen); 1 mi W Temascal (D.H.Janzen); 22.2mi N Puerto Escondido, 700m (D.H.Janzen); 25mi W Tehuantepec (D.H.Janzen); 3.2mi NETehuantepec (D.H.Janzen); 42km N San Pedro Pochutla, 850m (W.MacKay); 44mi W Tehuantepec (E.E.Gilbert & C.D.MacNeil); 5mi E Temascal (D.H.Janzen); 9.6km E Santiago Astata, 1 0m (W.MacKay ); Bahias de Huatulco (W.MacKay); Pinotepa Nacional (S.W.T.Batra); Salina Cruz (D.H.Janzen); Tehuantepec (F.Knab; W.P.Stoutamize); Temascal (H.V.Daly; D.H.Janzen); Temascal, 25m (D.H.Janzen);Tuxtepec(J.CamelaG.; W.M.Mann); Valle Nacional (G.V.Halffter); Q.Roo: 12.2mi S Peto, Q.Roo-Yucatan border (D.H.Janzen); 16.9mi W Cd. Chetumal. id. to Peto (D.H.Janzen); 22.5mi S Felipe Carillo Puerto (D.H.Janzen); 6.4mi E Polyuc (D.H.Janzen); 7mi W Felipe Carillo Puerto (D.H.Janzen); 8.1 mi S Felipe Carillo Puerto (D.H.Janzen); 8mi S Felipe Carillo Puerto (D.H.Janzen); Sian Ka'an (A.Dejean); Sian Ka'an Reserve, nr. Felipe Carillo Puerto (A.Dejean); Vallarta( A.Dejean); S.L.P.:27miN Tamazunchale (D.H.Janzen); 40-50mi NW Cd. del Maiz (W.S.Ross); 4miNValles, 300ft. (W.S.Creighton); Cd. Valles (D.H.Janzen); El Bonito, 7mi S Cd. Valles, 300ft. (P.H. & M.Arnaud); El Salto (A.Mintzer; c.u.); Huichihuayan (L.J.Lipovsky); Rio Amahac, Tamazunchale, 300ft. (W. S. Creighton); Tamazunchale (D. H. Janzen; W. S. Ross); locality not specified, prob. Tanquian [see Safford 1923:390] (Safford); Tab.: 0.6mi S Parafso on id. to Cardenas (D.H.Janzen); 0.9mi S Chontalpa (D.H.Janzen); 12.8mi S Chontalpa (D.H.Janzen); 2.1mi E Frontera (D.H.Janzen); 3 mi W Cardenas (D.H.Janzen); 30.2mi W Cd. El Carmen (D.H.Janzen); 37.8mi E Coatzacoalcos, Hwy.180 (D.H.Janzen); 6.6mi S Chontalpa (D.H.Janzen); Chontalpa, 26mi S Cardenas (D.H.Janzen); Cardenas (D.H.Janzen); Teapa (J.C. & D.Pallister; H.H.Smith; W.P.Stoutamize); Tamps.: 22.7mi S Cd. Victoria (D.H.Janzen); 41mi S Cd. Victoria (C.W.Obrien); 50mi N Valles (G.E.Bohart); 5mi N Cd. Mante (A.Mintzer); 7km WSW El Encino, 140m (P.S.Ward); Antiguo Morelos (c.u.); Cd. Madero (F.Infante M.); Ciudad Mante (N.E. & M.A.Evans; N.L.H.Krauss); El Limon (H.E.Evans); Forlon (L.J.Lipovsky); Gonzales (c.u.); Llera (W.E.LaBerge); Mesa de Llera (A.Mintzer); N of Antiguo Morelos (A.Mintzer); Rio Guayalejo at Volume 2, Number 1, 1993 141 Hwy.85 ( A.S.Menke & L. A.Stange); S of Cd. Mante (A.Mintzer);Tampico(Brakhoven; D.L.Crawford; H.Jourdan; N.L.H.Krauss: Locke; E. Palmer; E.A.Schwarz; W.P.Stephen; c.u. ); Tampico, dunes at Cd. Madero (D.H.Janzen); Xicotencatl (H.C.Millender); Ver.: "N.M.,Vera Cruz" (Townsend); "Vera Cruz" (G.Seurat; H.H.Smith); lOmi W Veracruz (G.E.Bohart); 14km ENE La Tinaja, 50m (P.S.Ward); 15mi W Veracruz (U.Kansas Mex.Exped.); 16km E Cuilahuac [=Cuitlahuac](W.MacKay);24.9miNWAcayucan (D.H.Janzen); 28km N Cardel, Morrode la Mancha (V.Rico-Gray); 30mi S Acayucan (F.D.Parker); 3mi N Sayula (R.C.Bechtel; R.C.Bechtel & E.I.Schlinger); 4mi NE Minatitlan (R.C.Bechtel & E.I.Schlinger); 4mi NW Rinconada Antigua, 1 350ft. (U.KansasMex.Exped.); 4mi W Puente Nacional, 900ft. (U.Kansas Mex.Exped.); 6.5km N Tierra Blanca, 50m (W.MacKay); 7mi S Cardel. 600ft. (c.u. ); 9km NNW Sontecomapan, 20m (P.S.Ward); Boca del Rio (U. Kansas Mex.Exped.); Buen Pais (R.C.Bechtel & E.I.Schlinger); Camaron (E.Skwarra); Cordoba (F.Knab;R.R.Snelling; c.u.); Cotaxtla Exp. Sta., Cotaxtla (D.H.Janzen); Est. Biol. Los Tuxtlas (H.A.Hespenheide); Est. Biol. "Los Tuxtlas", nr. San Andres Tuxtla (G.Ibarra M.); Fortin (c.u.); Jalapa (Rangel; W.M.Wheeler; c.u.); Jalapilla, mun. Jilotepec (G.Aleman); Los Cocos ( A. Petrunkewitch); Los Tuxtlas, 10km NNW Sontecomapan, 200m (P.S.Ward); Mirador (E.Skwarra); Mocambo (D.H.Janzen); Orizaba (c.u.); Palma Sola (Halffter & Reyes); Panuco (F.Parker & D.Miller): Playa Azul, Catemaco (W.P.Stoutamize); Pueblo Nuevo, nr. Tezonapa (Cornell Univ. Mex. Field Party); Remutadero (E.Skwarra); Santa Lucrecia [=Jesus Carranza] (F.Knab;P.Knab);Tamarindo (E.Skwarra); Tamos (F.C. Bishop); Tinajas [presumably La Tinaja, on Hwy. 1 50] (F.D.Parker & L. A.Stange); Tlacocintla (E.Skwarra); Veracruz (G.E.Bohart; N.L.H.Krauss; E.Skwarra; L.A.Stange); Yuc: 14.8mi S Ticul, "Hwy. 180" [prob.Hwy.261] (D.H.Janzen); 8mi E Merida (rd. to Pto. Juarez) (D.H.Janzen); Merida (D.H.Janzen; N.L.H.Krauss); Merida (S margin of town) (D.H.Janzen); Tekax, 33mi W Peto (D.H.Janzen); Temax (Gaumer); state unknown: "Mex"( "Norton"). Pseudomyrmex flavicornis (F. Smith 1 877 ) (Figs. 16,25,63,69) Pseudoniynna flavicornis F. Smith 1877:67. Lec- totypeworker.Nicaragua(BMNH) [Examined]. PseudomyrmabeltiEmery 1890:63. Syntype work- ers, Alajuela, Costa Rica (BMNH, MCSN) [Ex- amined] [Synonymy by Ward 1989:438]. Pseudoinyrma belti var. obnubila Menozzi 1927a:273. Syntype worker, San Jose, Costa Rica (H. Schmidt) (NHMB) [Examined] [Syn- onymy by Ward 1989:438]. Pseudoinyrma belti subsp. fellosa Wheeler 1942:160. Syntype workers, Nicaragua (W. Fluck); Granada, Nicaragua (C. F. Baker) (AMNH. LACM, MCZC) [Examined] [Syn- onymy by Ward 1989:439]. Pseudomyrmex flavicornis (F. Smith); Kempf 1972:218. Worker measurements (n = 29). — HL 1 .06- 1 .42, HW 0.99-1.21, MFC 0.075-0.114, CI 0.83-0.94, REL 0.39-0.45, REL2 0.45-0.51, OOI 1.28-2.71, VI 0.59-0.73, FCI 0.068-0.098, SI 0.40-0.46, SI2 0.82-0.97, NI 0.61-0.68, PLI 0.57-0.67, PWI 0.60- 0.72, PPWI 1.36-1.80. Worker diagnosis. — Similar to P. ferrugineus (q.v.) except as follows. Larger, with shorter eyes, on average (Figs. 16,50). Head densely punctulate, opaque; overlying rugulo-punctate sculpture on propodeum tending to be better developed than in P. ferrugineus. Pilosity and pubescence denser on average. Head black, gaster and postpetiole dark brown to black, mesosoma and petiole varying from black to a contrasting lighter brown or red- dish-brown; mandibles, scapes, fronto-clypeal com- plex, and apices of legs brown. Comments. — Key traits of this species are the laterally rounded median clypeal lobe, large size ( worker HW > 0.98; queen HW 1. 1 2- 1.1 9, n= 13), broad opaque head (worker CI > 0.82; queen CI 0.73-0.76) and dark color. P. flavicornis is one of three species in the P. ferrugineus group whose workers and queens have a black or very dark brown body (mesosoma sometimes contrastingly lighter). The other two, P. mi.xtecus and P. veneficus, are allopatric to P. flavicornis and smaller in size; 142 Journal of Hymenoptera Research other distinguishing features are mentioned in the key and discussed under those species. A tendency towards lighter coloration of the mesosoma in north- ern populations of P. flavicornis sometimes makes it difficult to distinguish this species from sympa- tric dark-colored P. ferrugineus. Even the darkest workers and queens of the latter species are, how- ever, smaller (an average difference in workers, almost absolute in P. ferrugineus queens which have HW 0.96- 1 . 12 (n= 37)) with longer eyes (Fig. 50) and shorter scapes for a given relative head breadth (Fig. 5 1 ); and they show some reflectance of light on the upper third of the head between the ocelli and compound eye in contrast to the more or less opaque-headed P. flavicornis. In addition, P. ferrugineus queens have more elongate heads (CI 0.68-0.73) than those of P. flavicornis. Distribution and biology. — This is a monogy- nous species ranging from Guatemala to Costa Rica (Fig. 69), which inhabits Acacia collinsii and, less frequently, A. cornigera and A. hindsii. It was one of the first acacia-ants to be brought to the attention of naturalists, thanks to an early account of its biology by Thomas Belt (1874) (under the name Pseudomyrma bicolor). In the more recent litera- ture P. flavicornis has usually been referred to as "P. belti", but note that there is not a perfect correspondence in name usage (Table 1 ). Material examined (AMNH, ANSP, BMNH, CASC, CUIC, INBC, LACM, MCSN, MCZC, MZSP, NHBM, NHMV, PSWC, SEMC. UCDC, USNM).— COSTA RICA Alajuela: Alajuela (A.Alfaro); Atenas(A.Alfaro);OjodeAgua(A.Alfaro);Tacares (A.Alfaro); Turrucares (A.Alfaro); Guanacaste: 1.4mi N La Cruz, 200m (D.H.Janzen); 10.7miNW Liberia (D.H.Janzen); 1km S Canas (D.H.Janzen); 2mi E Playa Coco (D.H.Janzen); 2mi SE Canas [=2mi S Canas] (D.H.Janzen); 4km S Canas(D.H.Janzen); 5km S Liberia (D.H.Janzen); 6mi E. 6mi S Canas (D.H.Janzen); 6mi W Liberia (D.H.Janzen); 7km N Canas (D.H.Janzen); Bahia del Coco (A.Alfaro); Ballena, Rio Tempisque (A.Alfaro); El Coco (R.J.Hampton); FincaTaboga, 6mi S, 6mi W Canas (D.H.Janzen); Hda. La Paeifica, 5km NW Canas (E.R.Heithaus); Hda. La Paeifica, nr. Canas, 50m (P.S.Ward); La Cueva, 12km N Liberia (D.H.Janzen); Liberia (A.Alfaro; M.G.Naumann); Palo Verde (D.E.Gill; H.A.Hespenheide; D.H.Janzen; D.Whitacre); Palo Verde, 50m (D.M.Olson); Palo Verde, <100m (J.Longino); RioCorobici,nr.Canas(R.M.Bohart); Santa Cruz (P.P.Calvert); Santa Rosa Natl. Pk. (F.Joyce); Santa Rosa Natl. Pk., 300m (J.Longino; P.S.Ward); Santa Rosa Natl. Pk., 5m (P.S.Ward); Santa Rosa Natl. Pk., <5m (P.S.Ward); Tempisque (A.Alfaro); Heredia: Lagunilla (C.H.Ballow); Puntarenas: 1km NE Tarcoles, 20m (P.S.Ward); 4km E Tivives, 5m (L.S.Farley); Barranca.near Puntarenas (A.Alfaro); San Jose: Bebedero (A.Alfaro); Rio Oro (D.H.Janzen); San Jose (Nauck;H. Schmidt); Villa Colon (A.Alfaro); Villa Colon, 600-700m (J.Longino); prov. unknown: "Costa Rica"(c.u.); Ciruela( J. F.Tristan). EL SALVADOR Ahuachapan: 7.8mi S Hachadura, 50m (D.H.Janzen); Chalatenango: 5.4miNLaPalma,850m(D.H.Janzen);LflL/Z? 0.86), laterally rounded median clypeal lobe, and uniform orange-brown color. P. janzeni is evidently closely related to P. ferrugineus (as surmised by Janzen 1973); all of the metric measurements and indices of these two species overlap, although there is a tendency for P. janzeni workers to have shorter, higher petioles (Fig. 48). Workers and queens of P. janzeni are perhaps best distinguished from those of P. ferrugineus by the combination of lighter orange-brown color, suberect gular pubescence (best seen in a backlit lateral view of the head), and the flatter profile of the worker mesosoma (see description above and Fig. 29). While some individuals of the highly variable P. ferrugineus approach these conditions there is no indication of a convergence towards this morphol- ogy in western Mexico (Guerrero) where popula- tions of P. ferrugineus come closest to those of P. janzeni. Distribution and biology. — First recognized by Janzen (1967a, 1969, 1973) as a distinct but undescribed species, P. janzeni is confined to a limited area in western Mexico (Fig. 70) where it is sympatric with the much darker colored and com- 144 Journal of Hymenoptera Research moner P. veneficus. Colonies occupy Acacia hindsii and are polygynous; additional details of the life history can be found in Janzen's (1973) paper on polygynous acacia-ants. Material examined. Type material listed above, plus the following (LACM. MCZC, PSWC, UCRC, USNM).— MEXICO Jai: Puerto Vallarta(J.A.Comstock); Nay.: 14.5mi E San Bias (D.H.Janzen); 2mi E San Bias (R.van den Bosch); 31mi N Tepic (D.H.Janzen); 36mi N Tepic (D.H.Janzen); 4mi E San Bias (M.Irwin; M.Irwin & E.I.Schlinger; E.I.Schlinger); 5mi E San Bias (F.Parker & D.Miller); Compostela (c.u.); Rio Palillo, 14mi E San Bias (D.H.Janzen); Tepic (H.A.Scullen); Sin.: 20mi E Villa Union (E.I.Schlinger). Pseudomyrmex mixtecus Ward, sp. nov. (Figs. 15,26,55,61,69) Holotype worker.— MEXICO, Guerrero: 25.4 mi. S. Chilpancingo, lO.viii. 1966, D. H. Janzen #M0088 10966 (LACM). HW 0.97, HL 1.07, EL 0.48, PL 0.55, PH 0.35. Paratypes. — Same data as holotype, and three other accession numbers (M0078 10966, M0098 10966, M0 108 10966) with same locality, date, and collector: series of 43 workers, 34 queens and 17 males (AMNH, BMNH. CASC. EBCC, GBFM, INBC, LACM, MCZC, MZSP, PSWC, UCDC, USNM). Additional non-type material is listed below. Worker measurements (n= 13 ). — HL 0.94- 1 . 1 9, HW 0.89-1.03, MFC 0.054-0.073, CI 0.86-0.95, RELO.42-0.47, REL2 0.46-0.52 OOI 1 .22-2.28, VI 0.6 1 -0.73, FCI 0.056-0.073, SI 0.43-0.45, SI2 0.86- 0.97, NI 0.60-0.65, PLI 0.60-0.68, PWI 0.60-0.68, PPWI 1.40-1.73. Worker diagnosis. — Similar to P. ferrugineus (q.v.) except as follows. Size smaller (HW< 1.04, LHT < 0.90), head broad (CI > 0.85); frontal carinae separated by about basal scape width or less (FCI2 0.45-0.54). Basal and declivitous faces of propodeum forming a less obtuse angle in profile than typical for P. ferrugineus (compare Figs. 26 and 27). Head densely punctulate, opaque. Stand- ing pilosity rather common, usually some setae exceeding 0.12 mm and 0.20 mm in length on mesosoma dorsum and petiole, respectively. Pu- bescence dense but appressed. Very dark brown to black, appendages lighter. Comments. — P. mixtecus is distinguished from all other species, except P. veneficus and P. flavicornis, by its laterally rounded median clypeal lobe, broad head, and black (or very dark brown) body. It differs from P. veneficus by the fully opaque head, absence of conspicuous suberect pu- bescence on the petiole, and larger size. P. mixtecus is evidently closely related to P. flavicornis but averages smaller in size (compare worker HW and LHT values), a difference which is absolute in queens (queen HW 0.96- 1.01 (n=8), whereas queen H W > 1 . 1 1 in P. flavicornis). In addition the petiole is relatively longer and higher, for a given head width, in both workers and queens of P. mixtecus (Figs. 44-47). Distribution and biology. — P. mixtecus is known only from the Mexican states of Guerrero and Oaxaca (Fig. 69). Colonies have been collected from Acacia hindsii and A. collinsii. but little more has been recorded about their biology. Janzen's field notes indicate that this species is monogynous. Material examined. Type material listed above, plus the following (CUIC, LACM, MCZC, MZSP, PSWC, SEMC. USNM, WPMC).— MEXICO Gro.: lOmi NE Acapulco (D.H.Janzen); 29.6mi N Acapulco, 1400ft. (D.H.Janzen); 30mi N Acapulco, Hwy.95 (Cornell Univ. Mex. Field Party); 57.8mi S Chilpancingo. Hwy.95 (D.H.Janzen); 74km N Acapulco (W.MacKay); Acapulco (Baker; F.Knab; N.L.H.Krauss; L.J.Lipovsky); Puerto Marques (N.L.H.Krauss); San Geronimo de Juarez (W.von Hagen); Oax.: 1 1 .4-17.0mi W Tehuantepec (D.H.Janzen); 13.8mi W Tehuantepec. 1500ft. (D.H.Janzen); 19km N San Pedro Pochutla, 200m (W.MacKay); 6.0mi E Niltepec, Hwy.190. 100m (D.H.Janzen). Pseudomyrmex nigroeinctus (Emery 1890) (Figs. 13,22,56.72) Pseudomyrma nigrocincta Emery 1 890:64. Syntype workers, queens, males. Alajuela, Costa Rica (A. Alfaro) (BMNH. MCSN. MCZC, MHNG) [Examined]. One syntype worker from MCSN Volume 2, Number 1. 1993 145 here designated LECTOTYPE. Pseudomyrma alfariForel 1906:228. Twosyntype workers, Tivives, embouchure de Jesus-Maria, Costa Rica (A. Alfaro) (MHNG) [Examined]. One syntype here designated LECTOTYPE. Syn. nov. Pseudomyrma nigrocinta var. bicincta Santschi 1922:347. Syntype workers, Costa Rica (MHNG, NHMB) [Examined]. One syntype from NHMB here designated LECTOTYPE. Syn. nov. Pseudomyrma peltata Menozzi 1927a:273. Three syntype workers, SanJose, Costa Rica (H. Schmidt) (NHMB) [Examined]. Syn. nov. Pseudomyrmex nigrocincta [sic] (Emery); Janzen 1966:252. Pseudomyrmex nigrocinctus (Emery); Kempf, 1972:221. Worker measurements {a = 2 1 ).— HL 0.89- 1 .08, HW 0.74-0.85. MFC 0.035-0.051, CI 0.75-0.84, REL 0.40-0.45, REL2 0.51-0.56, OOl 1.39-2.76, VI 0.62-0.78, FCI 0.044-0.065, SI 0.44-0.48. SI2 0.8 1 -0.89, NI 0.58-0.64, PLI 0.59-0.68, PWI 0.49- 0.61, PPWI 1.10-1.30. Worker diagnosis. — Small species with elon- gate head and short eyes (REL 0.45, REL2 0.56, EL/LHT 0.61). Palp formula 5,3. Median clypeal lobe rather narrow, its surface and anterior margin convex. Frontal carinae separated by about basal scape width (FCI 0.055). Metanotal groove well marked; basal and declivitous faces of propodeum subequal (Fig. 22). Petiole short (PLI > 0.57), its anterior peduncle broad in dorsal view (PWI3 0.50- 0.61) and not well differentiated from the node (Fig. 22). Petiole lacking expanded posterolateral corners. Postpetiole less broad than in most other species in the P. ferrugineus group (see PPWI values). Head densely punctulate and subopaque, becoming sublucid posteriorly where the punctulae are separated by shiny interspaces. Mesosoma punctulate to (laterally) coriarious-imbricate, sublucid, becoming subopaque on the propodeum. Standing pilosity moderately common (as in Fig. 22); pubescence dense and closely appressed. Or- ange-brown, often with anterolateral fuscous patches on abdominal tergite IV (these form a distinct transverse black band in queens). Comments. — Workers and queens of P. nigrocinctus are easily distinguished from all other acacia ants, except P. particeps (see below), by their small size ( HW < 0.86 in both castes), elongate head in the worker (worker CI < 0.85), and narrow petiole and postpetiole ( worker PWI3 0.50, worker PPWI 1 .30, queen PWI2 0.57-0.63 ). The orange color and short eyes are also characteristic. Distribution and biology. — P. nigrocinctus is found from Guatemala to Costa Rica, with most records coming from the southern end of its range (Fig. 72). Colonies are monogynous, and have been collected from Acacia collinsii, A. cornigera and A. hindsii. Records from Acacia gentlei and A. globulifera (Beulig & Janzen 1969:59) need to be confirmed because of possible confusion with P. peperi. Janzen's (1967b) observations on "P. nigrocincta" in Mexico refer to P. peperi. On the other hand descriptions of the biology and behavior of P. nigrocinctus in Costa Rica (Janzen 1973. 1974. 1975. 1983: Beulig & Janzen 1969) are reliably attributed to P. nigrocinctus. Material examined (AMNH, ANSP, INBC, LACM, MCSN, MCZC, MHNG, MZSP, NHMB, PSWC, USNM, WPMC).— COSTA RICA Alajuela: Alajuela (A.Alfaro); Atenas (A.Alfaro); Cascajal (A.Alfaro); Escobal (A.Alfaro); Ojo de Agua (A.Alfaro); Turrucares (P.P.Calvert); Guanacaste: 1.4mi N La Cruz (D.H.Janzen); 10.7mi NW Liberia (D.H.Janzen); lOmi NW Liberia, 70m (D.H.Janzen); lOmi NW Liberia, 70m [= 1 0.7mi NW Liberia] (D.H.Janzen); 2mi S Canas (D.H.Janzen); 4km N Canas (D.H.Janzen); 5km S Liberia (D.H.Janzen); 7km N Canas (D.H.Janzen); El Coco ( R.J.Hampton); Finca Taboga. 6mi S, 6mi W Canas (D.H.Janzen); Garita (A.Alfaro); Hda. La Pacifica, nr. Canas, 50m (P.S.Ward): La Cueva, 12km N Liberia (D.H.Janzen); Palo Verde (D.E.Gill; D.H.Janzen); Palo Verde, 50m (D.M.Olson); Santa Cruz (P.P.Calvert); Santa Rosa Natl. Pk., 290m (P.S.Ward); SantaRosaNatl.Pk.,300m(J.Longino; P.S.Ward); Santa Rosa Natl. Pk.. 5m (P.S.Ward); Santa Rosa Natl. Pk., <5m (P.S.Ward); Tempisque (A.Alfaro); Puntarenas: 2km E Tivives, <5m (L.S.Farley); Tivives (A.Alfaro); San Jose: 3.5km NE Santiago de Pur (D.H.Janzen); San Jose 146 Journal of Hymenoptera Research (H.Schmidt; c.u.); prow unknown: "Costa Rica" (c.u.). GUATEMALA Zacapa: 2.0mi NE Rio Hondo, 1 90m [on CA-9] ( D.H.Janzen); 22.3mi S W Quirigua [onCA-9](D.H.Janzen). HONDURAS Choluteca: 7.4miNECholuteca, 150m (D.H.Janzen). NICARAGUA Boaco: 1 1.7mi E San Benito (D.H.Janzen); Esteli: 13.1mi N San Isidro (D.H.Janzen); 2.5mi N Condega, 620m (D.H.Janzen); 6.8mi N San Isidro. 780m (D.H.Janzen); 7.5mi NW San Isidro, 550m (D.H.Janzen); Leon: Izapa (J.M.Maes); Madriz: 3mi W Somoto, 650m (D.H.Janzen); Matagalpa: 15.8mi NW Sebaco (D.H.Janzen); 2.6mi N Dario ( D.H.Janzen); 4. 5mi SE Dario (D.H.Janzen); 4mi S Dario, 350m (D.H.Janzen); Rivas: 1km W Peiias Blancas (D.H.Janzen); C.R. border, lmi N Peiias Blancas, <5m [ = lmi NW Penas Blancas] (D.H.Janzen); Isla Ometepe (F.Joyce). Pseudomyrmex particeps Ward, sp. nov. (Figs. 14, 23. 54, 57. 72) Holotype worker.— COSTA RICA, Puntarenas: Rincon, Peninsula Osa, 3.iii. 1965, D.H. Janzen #111 (LACM). HW0.83, HL 1 . 10, EL 0.50, PL 0.50, PH 0.31. Paratopes. — Same data as holotype: series of 82 workers, 14 males, one queen (AMNH. BMNH, CASC, GBFM. INBC, JTLC, LACM, MCZC, MZSP, PSWC, UCDC, USNM). Additional non- type material listed below. Worker measurements (n= 12).— HL0.93-1 . 10, HW 0.77-0.83, MFC 0.037-0.050, CI 0.75-0.84, REL 0.44-0.48, REL2 0.55-0.60, OOI 1.47-1.96, VI 0.65-0.75, FCI 0.048-0.062, SI 0.45-0.49, SI2 0.78-0.83, NI 0.53-0.62, PLI 0.58-0.66, PWI 0.55- 0.60, PPWI 1.03-1.26. Worker diagnosis. — Very similar to P. nigrocinctus (q.v.) except as follows. Eyes longer (REL2 0.55-0.60, EL/LHT 0.59-0.64) (Figs. 14, 42, 43). Front of head more strongly shining. Medium to dark brown; gaster uniformly dark brown or black; mandibles, fronto-clypeal com- plex, and appendages lighter brown. Comments. — P. particeps is obviously a very close relative of the allopatric P. nigrocinctus, but there are consistent differences between the two in eye size and color which exceed the limits of variation seen throughout the much wider range of P. nigrocinctus. Workers in the type series of P. particeps also have more elongate heads than those off. nigrocinctus but this distinction is not seen in other samples. Differences between queens of the two species are more striking with the two known queens of P. particeps having more elongate heads (CI 0.61, compared with 0.67-0.72 in a sample of 13 P. nigrocinctus queens) and longer metatibiae relative to head width (LHT/HW 1.12 versus 0.97-1.07 in P. nigrocinctus). Additional alates of P. particeps are needed to confirm these differ- ences and the apparent distinctions in male genita- lia (see male key). Distribution and biology. — P. particeps is a rare species known only from the Osa Peninsula and one adjacent locality, in Costa Rica (Fig. 72 ). It appears to be associated exclusively with Acacia allenii. a forest species (see Janzen, 1974 for more informa- tion aboutthehostplant). In contrast, P. nigrocinctus is found farther north in more open habitats where it typically inhabits Acacia collinsii. The differ- ences in worker morphology between P. particeps and P. nigrocinctus (darker color and more elon- gate head and/or eyes in the former) parallel those observed between populations of P. spinicola from the same areas (see below under P. spinicola), suggesting similar selection pressures associated with more forested habitats and partial (P. spinicola) or exclusive {P. particeps) occupancy of a different Acacia species. Material examined. Type material listed above, plus the following (JTLC, LACM, PSWC).- COSTA RICA Puntarenas: 4mi S Rincon (D.H.Janzen); Bahia Drake, Osa Penin. (F.Joyce); Corcovado Natl. PL, Sirena, 50m (J.T.Longino); Rincon ( A. R.Moldenke);&w./asT: 16.7miSWSan Isidro on Hwy.22, 160m (D.H.Janzen). Pseudomyrmex peperi ( Forel 1 9 1 3 ) (Figs. 12,24,58,71) Pseudomyrma peperi Forel 1913:213. Syntype workers, Patulul, Guatemala (Peper) (MHNG) [Examined]. One syntype here designated LECOTYPE. Volume 2, Number 1, 1993 147 Pseudomyrma spinicola race convarians Forel 1913:214. Syntype worker, Patulul, Guatemala (Peper) (MHNG) [Examined] [Synonymy by Ward 1989:452[. Pseudomyrma sabanica [sic] var. saffordi Enzmann 1945:89. Syntype workers, Yerba Santa, Chiapas, Mexico (G. N. Collins) (MCZC) [Ex- amined] One syntype here designated LECTO- TYPE. [Synonymy by Ward 1989:452]. Pseudomyrmex peperi (Forel); Kempf 1972:222. Worker measurements (n= 53). — HL0.86- 1.13, HW 0.76-0.90, MFC 0.034-0.064, CI 0.76-0.89, REL 0.45-0.50, REL2 0.54-0.62, OOI 1.15-2.06, VI 0.59-0.79. FCI 0.042-0.071, SI 0.44-0.49, SI2 0.76-0.88. NI 0.62-0.7 1 , PLI 0.54-0.65, PWI 0.63- 0.75, PPWI 1.41-1.83. Worker diagnosis. — Small species ( HW < 0.92 ) with moderately elongate head (Fig. 12); anterior margin of median clypeal lobe straight or slightly produced medially, laterally rounded or subangulate (never sharply angulate as in P. spinicola and P. satanicus). Palp formula 4,3, rarely 5p4,3. Frontal carinae separated by about basal scape width. Mesosomal and petiolar profile typically as in Fig. 24, but in some workers basal and declivitous faces of propodeum less well differentiated and/or anteroventral tooth of petiole more prominent. Petiole and postpetiole broad, the former subtriangular in dorsal view with well developed posterolateral angles (Fig. 24). Dorsum of head obscurely punctulate-coriarious, matte. Remainder of body with finely punctulate to punctulate- coriarious sculpture, opaque to sublucid; propodeum lacking overlying rugulo-punctate sculpture seen in P.ferrugineus. Standing pilosity not especially abundant, sometimes lacking (worn?) on mesonotum. Appressed pubescence abundant but very fine. Light to medium brown, rarely dark brown, the gaster sometimes darker than the rest of body; appendages lighter. Comments. — P. peperi is recognized by the fea- tures mentioned above and in the key. The combi- nation of small elongate head, broad posterolaterally angulate petiole, and matte head surface is found in no other acacia ant workers or queens. Distribution and biology. — This species has a rather wide distribution, from eastern Mexico to Nicaragua (Fig. 71). It has been collected from Acacia chiapensis, A. collinsii, A. cornigera, A. gentlei, A. globulifera and A. hindsii. P. peperi is apparently polygynous over much of its range, and often occurs sympatrically with the commoner P. ferrugineus. Some aspects of its biology in Mexico are discussed by Janzen ( 1 967b) under the name "'P. nigrocincta". Material examined (AMNH, BMNH, CASC, INHS, LACM. MCZC, MNHG. MZSP, NHMV, PSWC, SEMC, UCDC, USNM).- BELIZE Belize: 16mi SW Belize, id. to Cayo (D.H.Janzen); 5.5mi NW Belize, id. to Chetumal (D.HJanzen); Cayo: 20km S Augustine, 300m (G.D.Alpert);SanIgnacio(S.E.Schoenig);Co/-cca/: 15mi S Sta. Elena (Louisville) (D.H.Janzen). EL SALVADOR Ahuachapan: 7.8mi S Hachadura (D.H.Janzen); Chalatenango: 2.5mi N Tejutla.rd. to La Palma, 580m (D.H.Janzen); 4.7mi NW La Palma, 880m (D.H.Janzen); 5.5mi SE La Palma, 1130m (D.H.Janzen); 7.5mi SE Tejutla, 320m (D.H.Janzen); La Libertad: 2-4km S Quezaltepeque (W.L.Brown); 2mi E La Libertad (D.H.Janzen); 5mi N Quezaltepeque (M.E.Irwin); 7.4miN La Libertad (D.H.Janzen );Hda.Capolinas, 5kmNW Quezaltepeque, 450m (M.E.Irwin); Quezaltepeque (M.E.Irwin); Santa Tecla [=Nueva San Salvador] (P.Berry); La Union: 7.1 mi W Amatillo. 190m (D.H.Janzen); between La Union & San Miguel. 100m [=22.3mi S Sirama] (D.H.Janzen); between La Union &Usulatan, 150m [=2.6mi S Sirama] (D.H.Janzen); Lapaz: 1 1 .6mi W Zacatecoluca, 0m (D.H.Janzen); San Miguel: be- tween La Union & San Miguel, 1 10m [=22.3mi E Usulutan] (D.H.Janzen); Santa Ana: 5.3mi NW Santa Ana, 660m (on Hwy.l) (D.H.Janzen); Sonsonate: 24.2mi SE Hachadura (D.H.Janzen); 4.5mi S Sonsonate (D.H.Janzen); 41.4mi NW La Libertad, 10m (D.H.Janzen). GUATEMALA Aha Verapaz: San Joaquin, nr. San Cristobal Verapaz, 1080m (D.H.Janzen); El Progreso: 24.5mi NE Cd. Guatemala [on CA-9] (D.H.Janzen); Escuintla: 1.7mi S Escuintla, 370m [on CA-2] (D.H.Janzen); 43km S Cd. Guatemala [ = 15km E Escuintla] (D.H.Janzen); Escuintla (W.M.Wheeler); San Jose (E.S.Ross; E.I.Schlinger & E.S.Ross); Guatemala: 19km S Cd. Guatemala 148 Journal of Hymenoptera Research [on CA-9] (D.H.Janzen); 20mi SE Cd. Guatemala, 1060m [onCA-1] (D.H.Janzen); 7.9mi S Cd. Gua- temala, 1 360m [on CA-9] (D.H.Janzen );Escuintla- Cd. Guatemala [=19km S Cd. Guatemala] (D.H.Janzen); Izabal: 9.9mi SW Quirigua (D.H.Janzen); Lago Izabal, 1.5km NE El Estor (D.H.Janzen); Quirigua (D.H.Janzen; W.M.Wheeler); nr.Mariscos(D.H.Janzen);y«?/c//w: I 1.5mi W Jutiapa, 900m (D.H.Janzen); 12.3mi E Guazacapan (D.H.Janzen); 2.3mi NW Pijiji [=Pijije] (D.H.Janzen); 23mi E Taxisco (G.F. & S.Hevel); 3.4mi N San Cristobal, rd. to Jutiapa. 400m (D.H.Janzen); 47mi SE Escuintla, 250m [=47mi S Escuintla] (D.H.Janzen); 6.9mi N San Cristobal, 290m (D.H.Janzen); 8.4mi N San Cristobal. 280m (D.H.Janzen); 9.7mi E Jutiapa, 750m (hwy.to San Cristobal) [=9.3miNE Jutiapa] (D.H.Janzen);/3^/!: 70km NW Tikal (W.R.Tschinkel); Tikal ( D.H.Janzen; W.R.Tsch\nke\);Retallntleu:2miNE Champerico (D.H.Janzen); 5mi W Retalhuleu (D.H.Janzen); 5mi W Retalhuleu. Hwy.CA-2, at Rio Nil (D.H.Janzen); Santa Rosa: 6mi S Guazacapan (D.H.Janzen); Suchitepequez: Patulul (Peper); Zacapa: lOmiSWElLobo, 170m [on CA- 9] [=9.2mi NE Piedras de Afilar] (D.H.Janzen); 2.0mi NE Rio Hondo, 190m [on CA-9] (D.H.Janzen); 2.6mi SW El Lobo, 100m [on CA-9] [=16.6miNE Piedras de Afilar] (D.H.Janzen); 5. 6mi NE Rio Hondo, 250m [on CA-9] (D.H.Janzen); 8.1 mi SW Los Amates, 160m [on CA-9] [=8.0mi NE El Lobo] (D.H.Janzen); 9.7mi NE Piedras de Afilar, 150m [on CA-9] [=9.5mi SW El Lobo] (D.H.Janzen); Zacapa (W.M.Wheeler); km 142 on Guatemala-Pto. Barrios Rd. nr. Los Amates (D.H.Janzen). HONDURAS Choluteca: 19.3mi SW San Marcos de Colon, on Hwy.l (D.H.Janzen); 19mi NE Choluteca (D.H.Janzen); 20.4mi SW San Marcos de Colon, 490m (D.H.Janzen); 3.6mi W Choluteca, 200m (D.H.Janzen); 7.4mi NE Choluteca, 150m (D.H.Janzen); Colon: Trujillo, 80m (Echternacht); Comayagua: 11.7mi S San Antonio, 830m (D.H.Janzen); 4mi N Comayagua, 500m (D.H.Janzen); Cortes: 24.6mi SW San Pedro Sula, 240m (D.H.Janzen); Francisco Morazdn: 24.3mi S Camayaguela (=Tegucigalpa), 1000m (D.H.Janzen); 30.4mi S Camayaguela (D.H.Janzen); 30.5mi S Camayaguela, 930m (D.H.Janzen); Ocotepeque: 2.3mi E [Nueva] Ocotepeque, 1090m (D.H.Janzen); Nueva Ocotepeque, 910m (D.H.Janzen); Santa Barbara: 1 3.7mi SW Quimistan, 320m (D.H.Janzen); Valle: 18.5mi W Jicaro Galan (D.H.Janzen); 4.6mi E Jicaro Galan, 190m (D.H.Janzen). MEXICO Camp.: 0. 1 mi S Tenabo, rd. to Becal (D.H.Janzen); 0.8mi E Campeche (D.H.Janzen); 29mi E & 12mi S Campeche (Ruinas Edzna) (D.H.Janzen); 29mi E Campeche (D.H.Janzen); 48mi NE Puerto Real (Isla Aguada), Hwy.l 80 ( D.H.Janzen); 5mi S Tenabo (Campeche-Becal Rd. ) (D.H.Janzen); Campeche (N.L.H.Krauss); Chis.: 2.4mi E Chiapa de Corzo, Hwy.l 90, 580m (D.H.Janzen); 2km NYxhuatan[Ixhuatan],"2miN Tapilula" (D.H.Janzen); 32mi W [San] Cristobal de las Casas, Hwy.l 90 (D.H.Janzen); 3km ENE Chiapa de Corzo, 500m (P.S.Ward); 3mi N Soyalo [on Hwy.195] (D.H.Janzen); 42.5mi S Comitan, Hwy.190, 680m(D.H.Janzen); 5.4mi E Chiapa de Corzo, Hwy.190, 770m (D.H.Janzen); 56.9mi NE [NW?] Tapachula [on Hwy.200?] (D.H.Janzen); 7.0mi NE [NW?] Tapachula [on Hwy. 200?] (D.H.Janzen); 7.5mi NW Cd. Cuauhtemoc, Hwy.190 (D.H.Janzen); 8.5mi S La Trinitaria, Hwy. 190 (D.H.Janzen); Finca Esmeralda (R.Nettel F.); Puerto de San Benito [=Puerto Madero] (R.Nettel F.); Tonala, 40m (D.H.Janzen); Yerba Santa (G.N.Collins); Hgo. : 2km W Orizatlan, 245m (W.MacKay); Oax.: 11.4-17.0mi W Tehuantepec (D.H.Janzen); 19km N San Pedro Pochutla, 200m (W.MacKay); 3.9mi E Tehuantepec (D.H.Janzen); 5.7mi W "Tapanapec" [=Tapanatepec] (D.H.Janzen); 6.0mi E Niltepec .Hwy.l 90, 100m (D.H.Janzen); 8.1 mi W Niltepec, Hwy.190, 60m (D.H.Janzen); Temascal (D.H.Janzen); Temascal, 25m (D.H.Janzen); Q.Roo: 12.2mi S Peto, Q.Roo- Yucatan border (D.H.Janzen); 26.6mi S Felipe Carillo Puerto (D.H.Janzen); 5.4mi E Polyuc (D.H.Janzen); Cancun (A.Dejean); Cenote de Las Ruinas, 8km NW Polyuc (J. Red et al.); Chetumal (J.C. & D.Pallister); San Miguel, Cozumel I. (N.L.HKrauss);SianKa'an( A.Dejean); SianKa'an Reserve, nr. Felipe Carillo Puerto (A.Dejean); S.L.P.: 2mi N Rio Amahac, Tamazunchale, 400ft. (W.S.Creighton); 6mi NW Tamazunchale. 600ft. (Univ.Kansas Mex.Exped.); 8mi W San Joachin ( W.J.Gertsch); El Bonito, 7mi S Cd. Valles. Volume 2, Number 1, 1993 149 300ft. (P.H. & M.Arnaud); El Salto(W.E.LaBerge); Tamazunchale(D.H.Janzen);Tamazunchale, 600ft. (W.S.Creighton); Vet:: 29.5mi NW Tuxpan, Hwy. 1 22 [actually Hwy. 1 27] (D.H.Janzen); Alazan (F.Parker & D.Miller); Cordoba (W.M.Mann); CotaxtlaExp. Sta.,Cotaxtla(D.H.Janzen):Mirador (E.Skwarra): Veracruz (E.Skwarra); Yuc: 30mi S Merida (P.J.Spangler); 8mi E Merida (rd. to Pto. Juarez) (D.H.Janzen): Itzimna (J.C. & D.Pallister);Merida (D.H.Janzen; N.L.H.Krauss); Oxkutzcab (D.H.Janzen); Sta. Elena, S of Ticul, "Hwy. 180" |prob.Hwy.261] (D.H.Janzen); state unknown: "Mex"( "Norton"). NICARAGUA Esteli: lmi N Condega, 500m (D.H.Janzen); 2.5mi N Condega, 620m (D.H.Janzen); Leon: San Jacinto (J.M.Maes); Madriz: 3mi W Somoto, 650m [=2.5mi W Somoto] (D.H.Janzen); Nueva Segovia: 7. lmi W Amatillo (D.H.Janzen). Pseudomyrmex satanicus (Wheeler 1942) (Figs. 10,20,59,68) PseudomyrmasatanicaWheelei 1942: 174. Syntype workers, queen, male, Rio Agua Salud, Canal Zone, Panama (W. M. Wheeler) (AMNH. LACM, MCZC) [Examined]. One MCZC syntype worker here designated LECTOTYPE. Pseudomyrmex satanica [sic] (Wheeler); Janzen 1966:252. Pseudomyrmex satanicus (Wheeler); Kempt" 1972:223. Worker measurements (n= 15). — HL 1.16-1.36, HW 1.10-1.26. MFC 0.035-0.057, CI 0.90-0.97, REL 0.45-0.50, REL2 0.48-0.52, OOI 0.92-1.67, VI 0.69-0.78, FCI 0.030-0.049, SI 0.45-0.49. SI2 0.88- 1 .00, NI 0.63-0.68, PLI 0.47-0.54, PWI 0.46- 0.63, PPWI 1.35-1.54. Worker diagnosis. — Similartof . spinicola (q.v.) except as follows. Larger ( H W > 1 .09 ), head broader (CI > 0.88) (Fig. 34) with straight or slightly con- cave posterior margin and subangulate posterolat- eral corners (Fig. 10). (The posterior margin of the head approaches this condition in some P. spinicola workers but these have much smaller, more elon- gate heads, H W < 1 . 1 0. CI < 0.90. ) Median clypeal lobe narrower (CLW/HW 0.20-0.22; see Fig. 33). Palp formula 4,3. Head with pronounced pit-like impression below the median ocellus (absent or poorly developed in/5, spinicola). Metanotal groove better developed, longer. Petiole tending to be more slender, with less distinct posterolateral cor- ners (this characteristic seen in some workers off. spinicola, especially individuals from Panama). Body pubescence averaging thicker than in P. spinicola. Dark brown in color, mandibles and appendages lighter. Comments: — The foregoing diagnosis will al- low discrimination of P. satanicus workers from those of the closely related P. spinicola: queens can be recognized by size alone (HL > 1.65, HW > 1.20). P. satanicus can be distinguished from the remaining members of the P. ferrugineus group by the emarginate, laterally angulate median clypeal lobe of the worker and the large size of the queen. Distribution and biology. — P. satanicus is a forest species restricted to a few localities in central Panama where its host plant. Acacia melanoceras, grows (Fig. 68). Both the ant and plant are intoler- ant of forest clearance and are considered vulner- able to extinction (Janzen 1974). Theantispolygy- nous, with 5-20 or more queens per colony, and the workers are particularly aggressive, even for aca- cia-ants (Wheeler 1942; Janzen 1974). See Janzen (1974:43-53) for additional details on P. satanicus and its host plant. Material examined (AMNH, LACM, MCZC, PSWC, USNM).— PANAMA Canal Zone: "Canal Zone" (A.H.Jennings); 3mi SW Gattin Dam (D.H.Janzen); Bano Colorado Island (D.H.Janzen); France Field (G.C.Wheeler); Marajal [Majagual] nr. Colon (W.M.Wheeler); Red Tank (W.M.Wheeler); Rio Agua Salud (W.M.Wheeler); Zorra Island (D.H.Janzen); Panama: Rio Piedras (D.H.Janzen); prov. unknown: "Panama"(c.u.). Pseudomyrmex spinicola (Emery 1890) (Figs. 11,21,60,68) Pseudomyrma spinicola Emery 1890:64. Lecto- type worker. Alajuela, Costa Rica (Alfaro) (MCSN) [Examined]. Pseudomyrma spinicola race atrox Forel 1912:24. 150 Journal of Hymenoptera Research Syntype workers, Panama (Christophersen) (MHNG, NHMB) [Examinedl. Syn. nov. One syntype from MHNG here designated LECTO- TYPE. Pseudomyrma spinicola race Gaigei Forel 1914:615. Syntype workers, Columbien(Gaige) (MHNG), Fundacion, Colombia (F. M. Gaige) (LACM, MCZC) [Examined]. Syn. nov. Pseudomyrma spinicola subsp. infernalis Wheeler 1942:180. Syntype workers, queens, males, Venado, Canal Zone, Panama (W. M. Wheeler), RedTank, Canal Zone. Panama (W.M. Wheeler), and Las Sabanas, Panama (W. M. Wheeler) (AMNH, MCZC) [Examined]. One MCZC worker, from Red Tank, here designed LECTO- TYPE. Syn. nov. Pseudomyrma spinicola subsp. scelerosa Wheeler 1942:181. Syntype workers, Granada, Nicara- gua (C. F. Baker) (AMNH, MCZC) [Exam- ined] . One MCZC worker here designated LEC- TOTYPE. Syn. nov. Pseudomyrma spinolae [sic] var. infernalis Enzmann 1945:91. Syntype workers, queens, RedTank, Canal Zone, Panama (W. M. Wheeler) (MCZC) [Examined] [Objective synonym of P. spinicola subsp. infernalis Wheeler; Brown 1949:43]. Pseudomyrma spinolae [sic] var. scelerosa Enzmann 1945:91. Syntype workers, Granada, Nicaragua (C. F. Baker) (MCZC) [Examined] [Objective synonym of P. spinicola subsp. scelerosa, Wheeler; Brown 1949:43]. Pseudomyrmex spinicola (Emery); Wheeler and Wheeler 1956:386. Worker measurements (n=4l).— HL 0.99- 1.28, HW 0.94-1.15, MFC 0.032-0.067, CI 0.84-0.97, REL 0.42-0.47, REL2 0.45-0.54, OOI 1.22-2.77, VI 0.64-0.83, FCI 0.032-0.061, SI 0.45-0.50, SI2 0.88- 1 .05, NI 0.6 1 -0.69, PLI 0.47-0.64, PWI 0.49- 0.71, PPWI 1.32-1.85. Worker diagnosis. — Median clypeal lobe emar- ginate. laterally ungulate (Fig. 1 1 ), relatively broad (CLW/HW 0.21-0.25). Palp formula 5.3 (rarely 5p4,3). Frontal carinae relatively close, and me- dian lobes of antennal sclerites rather exposed (FCI2 0.24-0.42). Head longer thun broad but variably so (see range of CI values). Posterior margin of head ranging from broadly convex (Fig. 1 1 ) to straight or even weakly concave, usually rounding gently into the sides of head. Basal face of propodeum subequal to declivitous face, round- ing into latter; in dorsal view propodeal spiracles salient,protruding laterally. Petiole generally slen- der (PLI <0.65) with a well developed anterior peduncle; in dorsal view posterolateral angles typi- cally prominent. Head densely punctulate, sublucid, interspaces small (punctulae essentially contigu- ous on most of head) but shiny. Mesosoma finely punctulate dorsally becoming punctulate-coriarious laterally, sublucid; propodeum lacking overlying, coarser rugulo-punctate sculpture. Standing pilos- ity usually moderately common on body dorsum and including some hairs > 0.20 mm. Appressed pubescence common on most surfaces. Varying from light orange-brown to dark brown in color. Comments. — The short, broad, emarginate and laterally angulate median clypeal lobe (Fig. 11) distinguishes the worker of this species. The sublucid integument, elongate petiole, prominent propodeal spiracles, and somewhat angulate poste- rolateral corners of the petiole are also characteris- tic. In addition, queens and workers of P. spinicola have more elongate scapes and legs than those of all other species except P. satanicus (Figs. 30, 31). For differences between P. spinicola and the closely related P. satanicus see under the latter species. P. spinicola is a variable taxon and has received several infraspecific names, here considered junior synonyms. Southeastern populations (from the Rio Grande de Turcoles in Costu Ricu eust through Panama to northern Colombia) are somewhat dif- ferentiated from the others, with the workers and queens tending to have more elongate heads, darker color, and more slender petioles with less pro- nounced posterolateral angles (see Figs. 34, 35). In Costa Rica the contrasts between the two sets of populations are rather striking, and are perhaps accentuated by habitat differences since some (but not all) the southeastern populations are associated with Acacia allenii growing in forested situations, while the northern populations are primarily from Acacia collinsii in open habitats. Samples from Panama (all associated with A. collinsii) are more variable and partly bridge the phenotypic gap. It is possible that more than one species is masquerad- Volume 2, Number 1 , 1 993 151 ing in this variation but the evidence remains am- biguous. Distribution and biology. — P. spinicola is a monogynous species, distributed from Honduras to northern Colombia (Fig. 68), which is associated with Acacia collinsii and, less frequently. Acacia allenii and A. cornigera. Janzen (1983) provides a good summary of its biology in Costa Rica, under the name "P. ferruginea" . Observations on "P. ferruginea" in Costa Rica, Nicaragua, Panama and Isla Providencia (Janzen 1969, 1974, 1975, 1983) refer to P. spinicola; true P. ferrugineus does not occur south of Honduras and El Salvador. Material examined (AMNH, ANSP, BMNH, CUIC, FFIC, GBFM, GCWC, INBC, JTLC. KSUC, LACM, MCSN, MCZC, MHNG, MZSP, NHMB. PSWC, UCDC, USNM).— COLOMBIA Atlantico: Cuatro Bocas, 200m (J.F.G.Clarke); Bolivar: Hda. Monterey. 50m (G.Fagua; F.Fernandez); Magdalena: Aracataca (P.J.Darlington); Fundacion (F.M.Gaige); Fundacion, Santa Marta Mts.,300ft. (F.M.Gaige); San Andres y Providencia: "Old Providence Isl." (D.Fairchild); Isla Providencia, 300ft.(D.H.Janzen); dept. unknown: "Columbien" (Gaige). COSTA RICA Alajuela: Alajuela (A.Alfaro); San Mateo (P.Biolley); Surubres, nr. San Mateo (P.Biolley); Turrucares (A.Alfaro); Cartago: Turrialba (c.u.); Guanacaste: 10.7mi NW Liberia (D.H. Janzen); 2mi S Canas (D.H.Janzen); 5km S Liberia(D.H.Janzen);6miW Liberia (D.H.Janzen); 7km N Canas (D.H.Janzen); Canas, "La Pacifica" (R.L.Jeanne); Finca La Pacifica (D.W.Davidson); Garita (A.Alfaro); Hda. Comelco, 24km NW Canas (InterAm Hwy) (E.R.Heithaus); Hda. La Pacifica, nr. Canas, 50m (P.S.Ward); Palo Verde (D.E.Gill; E.Guerrant & P.Fiedler; H.A.Hespenheide; D.H.Janzen);Palo Verde, 50m (D.M.Olson); Palo Verde, < 1 00m ( J.Longino); Rio Corobici, nr. Cartas (R.M.Bohart); Santa RosaNatl.Pk.(E.M.Barrows); Santa Rosa Natl. Pk., 300m (J.Longino; P.S.Ward); Santa Rosa Natl. Pk., 5m (P.S.Ward); Santa Rosa Natl. Pk., <5m (P.S.Ward); Heredia: "15mi SE Pto.Viejo" [15km SW Pto.Viejo] (D.H.Janzen); Puntarenas: l-5mi NW Rincon (D.H.Janzen); 14.1 mi N Golfito (D.H.Janzen); 14km E Palmar Norte, 70m (P.S.Ward); 1km NE Tarcoles, 20m (P.S.Ward); 21.6 rd.mi NE Palmar Norte, 90m (D.H.Janzen); 3.4mi SE Golfito, 30m (D.H.Janzen); 4mi SW Rincon (D.H.Janzen); Corcovado Natl. Pk. (D.W.Davidson; J.T.Longino);Corcovado Natl. Pk.. Llorona (J.T.Longino); Corcovado Natl. Pk.. Sirena, 100m (P.S.Ward); Corcovado Natl. Pk., Sirena, 10m (P.S.Ward); Entrada Boruca, 20km NE Palmar Sur(D.H.Janzen);OsaPenin.,nr. Rincon (D.H.Janzen); Reserva Biol. Carara, 30m (P.S.Ward);Rincon (D.H.Janzen); RioTerraba, nr. Palmar Sur (D.H.Janzen); San Jose: 16.4mi SW San Isidro, 1 60m (D.H.Janzen); 3.5km NE Santiago de Pur (D.H.Janzen); Santa Ana (D.H.Janzen); Tarrazu [Rio?] (A.Alfaro); Villa Colon (A.Alfaro; D.H.Janzen); Villa Colon, 880m (A.Alfaro). HONDURAS Choluteca: 11.1 mi NECholuteca, 450m (D.H.Janzen); 3.6mi W Choluteca, 200m (D.H.Janzen); Colon: El Canal, Puerto Castilla (W.M.Mann); Roetan Isl. [Isla de Roatan] (M.Bates); Trujillo, 80m (Echternacht). NICARAGUA Boaco: Empalme do Boaco [=EI Empalme?] (Echternacht); Chontales: no spe- cific locality ( Janson); Este It: 7.5mi N W San Isidro, 550m (D.H.Janzen); Granada: Granada (C.F.Baker); Leon: 19mi SE Leon [=3.5mi N Pto.Somoza (Sandino)] (D.H.Janzen); 28.1 mi SE Leon (D.H.Janzen); Madriz: 13.9mi from Hondu- ras, on Nic.border, Hwy.l (D.H.Janzen); 2.5mi W Somoto ( D.H.Janzen); Managua: 20mi N Tipitapa, 90m [=19.4mi N Tipitapa] (D.H.Janzen); 8.1 mi E San Benito (D.H.Janzen); 9mi N Tipitapa. 50m [=8.8mi N Tipitapa] (D.H.Janzen); Matagalpa: 15.8mi NW Sebaco (D.H.Janzen); 2.6mi N Dario (D.H.Janzen); 4.1mi S Matagalpa, 650m ( D.H.Janzen); 4miS Dario. 350m [=4.5miSE Dario] (D.H.Janzen); 4mi S Dario, 350m (D.H.Janzen); Rivas: C.R. border, lmi N Penas Blancas, <5m [ = lmi NW Penas Blancas] (D.H.Janzen); Isla Ometepe ( F.Joyce); San Juan del Sur. 1 0m [= 1 mi N San Juan del Sur] (D.H.Janzen). PANAMA Canal Zone: 7.5mi NW Balboa (between Summit Gdn. &Paraiso) (D.H.Janzen); Ancon (S.F.Blake); Barro Colorado Island (We- ber); Cerro Galera (P.S.Ward); Chivachiva trail (W.M.Wheeler); Chivachiva trail, nr. Red Tank (W.M.Wheeler); Culebra [presumably CulebraCut] (D.D.Gaillard); E end of Madden Dam (D.H.Janzen); Gamboa (N.Banks); Howard AFB, 152 Journal of Hymenoptera Research W of Panama City, 50m (W.L.Brown et al.); Mad- den Dam (D.Quintero et al.); Paraiso (A.Busck); RedTank (W.M.Wheeler); Ruta 1, 14kmWPanama City. 100m (W.L.Brown et al.); Venado (W.M.Wheeler); W end Madden Dam (D.H.Janzen); Chiriqui: 10.7mi ESE Concepcion (D.H.Janzen); 12.9mi E Remedios (D.H.Janzen); 19.6mi E Sapotilla, 50m (D.H.Janzen); 7.2mi W Remedios (D.H.Janzen); 9.5mi S Boquete, 620m (D.H.Janzen); Code: 0.3mi W Agua Dulce, 50m (D.H.Janzen); 10.4miNE Santa Maria, 60m [=1.9mi W Agua Dulce, Hwy. 1] (D.H.Janzen); 2.7mi SW Penonome (D.H.Janzen); Herrera: Cerro Guacamaya, Albina alN.de Monagrillo ( D.Quintero et al.); Los Santos: 3.1 mi N Pedasi (D.H.Janzen); Azuero Penin., 5.4mi SE Los Santos, <5m (D.H.Janzen); Panama: 18.6mi SW Chepo (D.H.Janzen); Bella Vista (N.Banks); Las Sabanas (G.C.Wheeler; W.M.Wheeler); Las Sabanas, Panama City (H.F.Dietz); Rio Corona, S of El Valle, 2000ft. (C.W.Rettenmeyer); Rio Tetita, San Carlos (F.D.Rattinibane); savannah nr. Juan Diaz (Weber); Veraguasi'l): LasPalmas(c.u.); Veraguas: 4km NW Santiago (D.Quintero); prow unknown: "Panama" (Christophersen). Pseudomyrmex veneficus (Wheeler 1942) (Figs. 17,28,62,69) Pseudomyrma belti subsp. venefica Wheeler 1942:162. Syntype workers, males, queens, Escuinapa, Sinaloa, Mexico (J. H. Batty) (AMNH, MCZC) [Examined]. One MCZC syntype worker here designed LECTOTYPE. Pseudomyrma belti subsp. venifica Enzmann 1945:81. Syntype workers, queens, Manzanillo, Colima, Mexico (C. H. T. Townsend) (MCZC) [Examined] [Synonymy by Brown 1949:42]. Pseudomyrmex venefica [sic] (Wheeler); Janzen 1969:241. Pseudomyrmex belti veneficus (Wheeler); Kempf 1972:216. Pseudomyrmex veneficus (Wheeler); Ward 1989:439. Worker measurements (n = 1 2 ). — HL 0.95-1 .04, HW 0.85-0.95, MFC 0.045-0.073, CI 0.88-0.95, REL 0.44-0.47, REL2 0.47-0.52, OOI 1.26-2.30, VI 0.66-0.75, FCI 0.051-0.081, SI 0.43-0.46, SI2 0.85-0.94, NI 0.58-0.65, PLI 0.60-0.67, PWI 0.58- 0.67, PPWI 1.35-1.73. Worker diagnosis. — Similar to P. ferrugineus (q.v.) except as follows. Smaller (LHT 0.69-0.80), with broad head (CI > 0.87); frontal carinae sepa- rated by basal scape width or less (FCI2 0.40-0.60); petiole short (PL 0.43-0.54) and relatively narrow (see PWI values) with somewhat rounded postero- lateral angles (Fig. 28). Head densely punctulate, subopaque to sublucid, with weak silvery reflec- tance. Overlying rugulo-punctate sculpture on propodeum weak and ill-defined. Standing pilosity variable in abundance, becoming rather short ( 0. 10 mm) and sparse in southern populations. Pu- bescence thick and conspicuous, suberect on some surfaces especially the propodeum and petiole; suberect pubescence on petiolar dorsum contrast- ing with the appressed pubescence on the postpetiole (Fig. 28). Very dark greyish-brown to black, parts of the mesosoma and petiole sometimes with lighter yellowish brown ( more consistently so in the queen ). Comments. — The small size ( worker HW< 0.96; queen HW 0.84-0.96, n=12), conspicuous suberect pubescence on the propodeum and petiole, and black coloration of the head and gaster distinguish workers and queens of P. veneficus. The related species, P. fiavicornis, is larger (worker HW > 0.98, queen HW 1.12-1.19) with a broader and more robust petiole (Figs. 25, 28). Workers and queens of P. fiavicornis also lack the sublucid head and conspicuous suberect pubescence characteris- tic of P. veneficus. P. mixtecus is somewhat inter- mediate between these two - it has the head sculp- ture and pubescence typical of P. fiavicornis but approaches P. veneficus in size (worker and queen head widths overlapping, although only slighter in the queens where HW 0.96-1.01 (n=8) in P. mixtecus) and petiolar dimensions (Figs. 44-47). Distribution and biology. — P. veneficus has a limited distribution in western Mexico (Sinaloa to Michoacan) (Fig. 69) where colonies occupy Aca- cia hindsii and, at one locality. A. collinsii. Janzen ( 1973) gives a detailed description of the ecology and behavior of this highly polygynous, effectively unicolonial, species whose colonies are among the largest of all social insects (containing millions of workers and several hundred thousand queens). Volume 2, Number 1, 1993 153 Material examined (AMNH, CASC, EBCC, INHS, LACM, MCSN, MCZC, MZSP, PSWC, UCDC, UCRC, USNM).— MEXICO Col.: 9.4mi NW Manzanillo (D.H.Janzen); Manzanillo (C.H.T.Townsend; W.M.Wheeler); Paso del Rio, 200ft. (I.J.Cantrall); Jal: 2km E Chamela, 20m (P.S.Ward); 5km E Chamela, 50m (P.S.Ward); 6mi NE El Rincon, 1600ft. (R.J.Hamton); Barra de Navidad (N.L.H.Krauss); Chamela (R.J.McGinley; J.F.WatkinsKMc^: 1.1 mi N Gabriel Zamora, 820m (D.H.Janzen); 1.5miNLaMira(D.H.Janzen); 15km WNW Playa Azul, 50m (P.S.Ward); Nay.: 12mi NE San Bias (W.J.Gertsch & W.Ivie); 16mi NW Tepic ( W.E.LaBerge); 3 1 mi N Tepic ( D.H.Janzen); 37mi N Tepic (D.H.Janzen); 4mi E San Bias (M.E.Irwin); Rio Palillo, 14mi E San Bias (D.H.Janzen); Sin.: 14.6mi S Mazatlan ( D.H.Janzen); 20mi E Villa Union (E.I.Schlinger); 20miE Villa Union, 235m (M.E. Irwin; E.Schlinger et al.); 20mi S Villa Union (E.I.Schlinger); 5mi E Concordia (W.J.Gertsch & J.A.Woods); Escuinapa (J. H. Batty); Palmito (L.de Mauzo); Piedra Blanca (R.M.Bohart); state unknown: "Mexico"(cu.). OTHER ACACIA-ASSOCIATED Figs. 67- 72. Distributions of species in the Pseudomyrmexferrugineus group. 154 Journal of Hymenoptera Research PSEUDOMYRMEX FROM CENTRAL AMERICA Introduction Three of the species discussed below (Pseudomyrmex nigropilosus, P. simulans and P. subtilissimus) are obligate inhabitants of Central American swollen-thorn acacias, although they are not closely related to the P. ferrugineus group (Ward 1991). A fourth species, P. reconditus, is known only from a single collection, made in association with Acacia collinsii. The remaining six species (P. boopis, P. gracilis, P. hesperius, P. ita, P. kuenckeli and P. opaciceps) are non-special- ist Pseudomyrmex which have been collected only occasionally from acacias. These taxa are included for completeness, and their presentation here ne- cessitates a certain amount of taxonomic house- cleaning. One could expect additional generalist Pseudomyrmex to be found in living or dead acacia thorns. Menozzi (1927b) mentions collections by H. Schmidt of "Pseudomyrma flavidula" and "P. brunnea" from Acacia "spadicigera" (probably A. collinsii) near San Jose, Costa Rica. I have not examined the ant specimens in question but they probably belong to P. pallidus (F. Smith) and P. ejectus (F. Smith), respectively. Diagnoses of these species appear in Ward (1985). Finally, mention should be made of other Neotropical acacias which are apparently not myrmeeophytes, but which may harbor opportunistic Pseudomyrmex species in their spines: Acacia daemon in Cuba with P. pazosi, P. simplex and P. cubaensis (Berazafn & Rodriguez 1983; Pseudomyrmex nomenclature follows Ward 1989), and A. caven in Paraguay with P. gracilis (s.l.) and one or more species in the P. pallidus group (Wheeler 1942; Ward 1991 ). Synonymic list of species P. boopis (Roger 1863b) = P. modestus (F. Smith 1862) (preoccupied) = P. thoracicus (Norton 1868b) syn. nov. = P. excavatus (Mayr 1870) (Kempf 1967) = P.flaviventris (Emery 1896) (Kempf 1960) = P.fusciceps (Santschi 1931 ) (Kempf 1960) = P. guatemalensis (Enzmann 1945) (Kempf 1960) P. gracilis (Fabricius 1804) = P. bicolor (Guerin 1844) syn. nov. = P. sericatus (F. Smith 1855) syn. nov. = P. dimidiatus (Roger 1863a) syn. nov. = P. mexicanus (Roger 1863a) syn. nov. = P. variabilis (F. Smith 1877) (Ward 1989) = P. pilosulus (F. Smith 1877) syn. nov. = P. volatilis (F. Smith 1877) syn. nov. = P. canescens (F. Smith 1877) syn. nov. = P. guayaquilensis (Forel 1907) (unavailable name) = P. glabriventris (Santschi 1922) syn. nov. = P. veliferus (Stitz 1933) syn. nov. = P. longinodus (Enzmann 1945) (Brown 1949) P. hesperius, sp. nov. P. ita (Forel 1906) stat. nov. = P. acaciarum (Wheeler 1942) syn. nov. = P. acaciorum (Enzmann 1945) (Brown 1949) P. kuenckeli (Emery 1890) = P. dichrous (Forel 1904) (Kempf 1961 ) = P. bierigi (Santschi 1932) (Kempf 1961 ) = P. crenulatus (Enzmann 1945) (Kempf 1961 ) P. nigropilosus (Emery 1890) P. opaciceps, sp. nov. P. reconditus, sp. nov. P. simulans Kempf 1958 P. subtilissimus (Emery 1890) SPECIES ACCOUNTS Pseudomyrmex boopis (Roger 1863b) (Fig. 1 ) Pseudomyrma modesta F. Smith 1862:32. Holo- type ( unique sy ntype ) worker, Panama ( Stretch ) (BMNH) [Examined]. [Preoccupied by P. modesta F. Smith 1860 = Tetraponera modesta (F. Smith).] Pseudomyrma boopis Roger 1863b:25. Replace- ment name for Pseudomyrma modesta. Pseudomyrma thoracica Norton 1 868b:8. Syntype workers, Cordova, Mexico (Sumichrast) [Not examined; see comments below]. Syn. nov. Pseudomyrma excavata Mayr 1870:410. Syntype workers, "N. Granada" (BMNH, MHNG, NHMV) [Examined] [Synonymy by Kempf Volume 2, Number 1, 1993 155 1967:2]. Pseudomyrma excavata var. flaviventris Emery 1896:2. Syntype workers, Darien, Panama (Festa) (MCSN, MHNG) [Examined] [Syn- onymy by Kempt" 1960:22]. Pseudomyrma excavata var. fusciceps Santschi 1931:271. Two syntype workers, France Field, Panama ( A. BierigMNHMB) [Examined] [Syn- onymy by Kempt" 1960:22]. Pseudomyrma spinicola subsp. modesta F. Smith: Wheeler 1942:105. Pseudomyrma tenuis var. guatemalensis Enzmann 1945:92. Holotype worker, Escuintla. Guate- mala [Not examined] [Synonymy by Kempt" 1960:22]. Pseudomyrmex boopis (Roger); Kempf 1967:2. Workerdiagnosis. — Medium-sized species (HW 1 . 1 6- 1 .29) in the P. tenuis group, with a broad head (CI 0.92-1.02). tectiform and laterally rounded median clypeal lobe, large eyes (REL 0.66). and laterally marginate pronotum. Mesosoma arched and angular in profile; petiole short, high and thin, laterally marginate, with a gently ascending anterodorsal face which rounds into a much steeper (almost vertical) posterior face (Fig. 1). Standing pilosity sparse, lacking on the mesonotum, propodeum, and petiole. Color highly variable, ranging from light testaceous brown to bicolored orange and black (usually with the gaster and pronotum lightest in color) to dark brown. Taxonomic comments. — For a more detailed description of this species see Kempf (1960:23). I have synonymized P. thoracicus (Norton) under P. boopis on the basis of Norton's (1868b) original description and the biological notes of Sumichrast in Norton (1868a). In combination these clearly suggest P. boopis rather than any other Pseudomyrmex known to occur in southern Mexico. Although the type material of P. thoracicus is presumably lost, additional indirect evidence of its identity can be found in Gustav Mayr's collection in Vienna (NHMV) where there is a P. boopis worker from Colombia ("Neugranada") identified by Mayr as "P. thoracica Norton". This take son added significance when it is realized that Mayr was apparently the recipient of some of Norton's material. During a brief visit to NHMV I noted specimens of several species, including P. ferrugineus, P. peperi, P. elongatulus ( Dalla Torre ) and P. brunneus (F. Smith ) ( although unfortunately not P. boopis), labelled "Mex. Norton" or "N.Am./ Norton". Distribution and biology. — P. boopis occurs in rainforest and tropical moist forest from southern Mexico to Ecuador, Venezuela and northern Brazil. This species is less arboreal than most Pseudomyrmex, and nests typically in rotten wood on or near the ground. The type specimen of P. boopis came from a nest in a swollen-thorn acacia (Smith 1 862:33 ), however, and Janzen found colo- nies in thorns of Acacia melanoceras seedlings in Panama. Pseudomyrmex gracilis (Fabricius 1804) (Fig. 6) Formica gracilis Fabricius 1804:405. Lectotype worker, Essequibo, Guyana (ZMUC) [Exam- ined]. Pseudomyrma bicolor Guerin 1844:427. Syntype queen (unique?), Colombia (ZSMC) [Exam- ined] Syn. nov. Pseudomyrma sericata F. Smith 1855:159. Holo- type (unique syntype) worker, Brazil (BMNH) [Examined] Syn. nov. Pseudomyrma dimidiataRoger 1863a: 177. Syntype workers, Colombia (not in MNHN or ZMHB) [Not examined] Syn. nov. Pseudomyrma mexicana Roger 1 863a: 178. Syntype workers, Mexico (not in MNHN or ZMHB) [Not examined] Syn. nov. Pseudomyrma variabilis F. Smith 1877:62. Lecto- type worker, Barbadoes (BMNH) [Examined] [Synonymy by Ward 1989:439]. Pseudomyrma pilosula F. Smith 1877:62. Two syntype workers, Barbadoes (BMNH) [Exam- ined]. One syntype here designated LECTO- TYPE. Syn. nov. Pseudomyrma volatilis F. Smith 1877:65. Holo- type (unique syntype) male, Mexico (BMNH) [Examined] Syn. nov. Pseudomyrma canescensF. Smith 1877:66. Holo- type (unique syntype) queen, Abydos, Brazil (BMNH) [Examined] Syn. nov. 156 Journal of Hymenoptera Research Pseudomyrma gracilis var. glabriventris Santschi 1922: 345 . Sy ntype workers, Izozo, Bol i via ( Lizer & Deletang) (NHMB) [Examined] Syn. nov. Pseudomyrma gracilis mexicana var. guayaquilensis Forel 1907:7. Worker, Guayaquil, Ecuador (Buchwald) (MHNG) [Ex- amined] Unavailable infrasubspecific name. Pseudomyrma gracilis var. velifera Stitz 1933:68. Holotype queen, Champerico, Guatemala (Paessler) (not in ZMUH; Weidner 1972) [Not examined] Syn. nov. Pseudomyrma gracilis var. longinoda Enzmann 1945:87. Syntype worker, Peru (MCZC) [Ex- amined] [Synonymy by Brown 1949:43]. Pseudomyrme.x gracilis (Fabricius); Kusnezov 1953:214. Worker diagnosis. — With the traits of the gracilis group (see couplet 6 of the key; p. 1 30) and the following more specific features. Head broad, about as wide as long (CI 0.95-1.08); anterior margin of median clypeal lobe straight to broadly convex, rounded laterally; pronotum dorsolaterally margin- ate but not sharply so; in lateral view mesonotum more steeply inclined than basal face of propodeum; petiole long and slender (PLI 0.46-0.57) with a distinct anterior peduncle ( Figs. 6,53); head densely punctulate with a subopaque to sublucid (not matte ) appearance; standing pilosity abundant, fine, pre- dominantly pale silvery-white (not black). Size and color extremely variable (HW 1.39- 2.07 ). varying from unicolorous black ( appendages lighter) to unicolorous orange-brown, with many intermediate and bicolored combinations. In popu- lations from Mesoamerica the gaster is typically black, or if paler (orange-brown) then it is usually accompanied by a similar light coloration of the mesosoma (and sometimes also the head). Taxonomic comments. — The P. gracilis com- plex presents one of the more taxonomically chal- lenging problems in the genus Pseudomyrme.x and the above treatment is by no means a final solution. The worker- and queen-based forms, newly syn- onymized under P. gracilis, fall within the bounds of the preceding diagnosis, but it is quite possible that my concept of this species will prove to be too broad. The types off. dimidiatus, P. mexicaniis and P. veliferus could not be located. They are judged to be junior synonyms on the basis of the original descriptions. The unique male holotype of P. volatilis is clearly a member of the P. gracilis group based on size (HW 1.48), mandibular dentition, pilosity, petiole shape, and shape of the parameres. In comparison with males of gracilis group species known to occur in Mexico, namely P. gracilis, P. major (see below ), P. nigropilosus and P. opaciceps, the type specimen agrees best with P. gracilis. The concept of P. gracilis adopted above en- compasses an impressive amount of phenotypic variability. Collections from single regions often give the impression that this variation is distributed bimodally or multimodally, as more or less discrete morphs. For example, nest samples from Costa Rica can be segregated on the basis of worker morphology into (i) a large (HW > 1.80), usually lighter-colored form (with orange mesosoma, peti- ole, and postpetiole, and black head and gaster), (ii) a smaller, bicolored, usually more heavily infuscated form, and (iii) an all-black form of variable size. The first two are typically found in open or xeric habitats while the third is more common in closed forest, suggesting some ecotypic differentiation. Yet when large enough sample sizes are obtained all degrees of intermediacy in size and color are encountered, and the variation in color ( less so size ) can be seen among individuals (workers and alate queens) from the same nest. Thus, if there are ecotypes they do not appear to be reproductively isolated. Left unresolved after the establishment of the above synonymy is the relationship of P. gracilis to the following nominal taxa: P. alternans (Santschi ), P. gracilis atrinodus (Santschi), P. gracilis argentinus (Santschi) and P. santschii (Enzmann). But the following deserves recognition as a distinct species: Pseudomyrmex major (Forel 1899:91), stat. nov. (syntype worker, Pinos Altos, Chihua- hua, Mexico (Buchan-Hepburn) (BMNH) (exam- ined); original combination: Pseudomyrma gracilis var. major). Workers of P. major can be distin- guished from those off. gracilis by their emargin- ate median clypeal lobe, less distinct anterior pe- duncle of the petiole, and larger average size. Males of P. major have broadened fore-tarsal segments. P. major is confined to western Mexico, where it occurs sympatrically with P. gracilis without show- Volume 2, Number 1, 1993 157 ing signs of intergradation. Distribution and biology. — Befitting its wide distribution (southern United States to Argentina and Brazil) and variable phenotype, P. gracilis can be found in a variety of habitats from mangroves and thorn scrub to rainforest. It is often particularly common in disturbed situations such as old fields, roadsides, and secondary forest. Nests are usually located in dead twigs or small branches, but there are a substantial number of records of colonies occupying swollen-thorn acacias in Central America (Mexico to Panama). In a few localities P. gracilis is a common acacia inhabitant and under these circumstances it may exhibit local adaptation and phenotypic differentiation (see also Wheeler 1942:107). For example, Janzen collected a series of specimens from Acacia gentlei in Belize ( 1 5 mi. S Santa Elena) which have somewhat distinctive morphology: the workers are large, dark, abun- dantly hairy, and possess rather short petioles (PLI 0.55), although none of these features is outside the total range of variation for the species. Janzen (1974:98) notes that the workers of this large black morph have atypically aggressive behavior. Given the kind of ecotypic variation to which P. gracilis is prone, it is not surprising to find a tendency of some populations to specialize on acacias. The ecology of this species is reminiscent of other animal spe- cies which show broad ecophenotypic variation, e.g. fish with trophic polymorphisms (Kornfield et al. 1 982; Grudzien and Turner 1 984; Sandlund et al. 1992). Pseudomyrmex hesperius Ward, sp. nov. (Fig. 4) Holotype worker.— MEXICO Sinaloa: 1 5.9 mi. NE Concordia, Hwy. 40, 600m, 9.vi.l967, D. H. Janzen XVIII, ex Acacia hindsii (LACM). HW 0.66. HL 0.83, EL 0.36, PL 0.34. PH 0.26. Paratypes. — Same data as holotype: series of 1 1 workers (BMNH, LACM, MCZC, MZSP, PSWC, USNM). Additional non-type material. — MEXICO Sinaloa: 14 km. S Mazatlan, 18.vii.1965. R. R. Snelling. 15 workers (LACM, MCZC, PSWC). Worker measurements (n=6). — HL 0.78-0.85, HW 0.65-0.69, MFC 0.028-0.043. CI 0.79-0.83, REL 0.43-0.46, REL2 0.54-0.57, OOI 0.86-1.15, VI 0.75-0.82, FCI 0.043-0.062, SI 0.48-0.51, SI2 0.87-0.93, FI 0.4 1-0.45, PDI 0.84-0.95, MPI 0.053- 0.066, NI 0.54-0.59, PLI 0.73-0.77. PWI 0.63-0.70. PPWI 1.41-1.56. Worker diagnosis. — Small species (see above measurements ) with elongate, subrectangular head and short eyes (REL 0.43-0.46, OI 0.61-0.65). Masticatory margin of mandible with five teeth, the fourth tooth (counting from the apex) separated by a gap of ca. 0.05 mm from the apicobasal tooth; MD8/MD9 0.70; third and fourth teeth small, contrasting with the large subapical and apical teeth ( the latter ca. 0.032 and 0.055 mm in length, respec- tively); mesial tooth on basal margin situated slightly closer to apicobasal tooth than to proximal tooth (MD4/MD5 0.65); palp formula 5,3; median clypeal lobe short, its anterior margin straight to weakly convex, sharply rounded laterally; mini- mum distance between frontal carinae subequal to or less than basal scape width; frontal carinae diverging anteriorly and fusing with the antennal sclerites; pronotum laterally rounded, without hu- meral angles; in lateral profile the mesonotum and basal face of propodeum slightly inclined anteri- orly, separated by a well developed metanotal groove (Fig. 4); basal face of propodeum rounding into the longer declivitous face, the latter somewhat con- cave in profile; petiole short, apedunculate. shaped as in Fig. 4, with a prominent triangular anteroventral tooth; in dorsal view petiole very broad anteriorly (PWI3 0.59-0.62); postpetiole broader than long, its anteroventral process small and inconspicuous. Mandibles finely striate; head punctulate on a smooth shining background, punctulae separated by one to several diameters on upper half of head, becoming denser towards the clypeus; mesosoma sublucid. with weak punctulate-coriarious sculp- ture; petiole, postpetiole and gaster shining, with very fine piligerous punctures. Standing pilosity common but short (< 0.10 mm) on most parts of body, lacking on outer faces of tibiae. Appressed pubescence widely distributed, moderately dense on abdominal tergite IV. Dark brown; mandibles, appendages and fronto-clypeal complex tending towards a lighter brown. Taxonomic comments. — This is a taxonomi- cally isolated species, not belonging to any of the 158 Journal of Hymenoptera Research nine major species groups of Pseudomyrmex (see Ward 1989). The salient features of P. hesperius are small size (HW <0.72), reduced mandibular denti- tion and palp formula, short truncate median clypeal lobe, short eyes (especially obvious in lateral view, such that OI > 0.60), short apedunculate petiole with a broad attachment to the propodeum (PWI3 0.60), punctulate head sculpture, sublucid integu- ment, and short standing pilosity. Some of these traits are shared with two other Mesoamerican Pseudomyrmex, P. fervidus (F. Smith) and a re- lated undescribed species, but both of these are larger (HW > 0.70), with standing pilosity which is longer and more extensive (present on the outer faces of the tibiae). Biology. — Although the type specimens of P. hesperius were collected from Acacia hindsii this species is not an obligate acacia inhabitant. The series from 14 km. south of Mazatlan was collected from dead branches of a woody plant, not Acacia (R. R. Snelling, pers. comm.). Pseudomyrmex ita (Forel 1906) stat. nov. (Fig. 2) Pseudomyrma sericea var. ita Forel 1906:230. Syntype workers, San Mateo, Costa Rica (P. Biolley) (MHNG) [Examined]. One syntype here designated LECTOTYPE. Pseudomyrma sericea var. acaciarum Wheeler 1942:176. Syntype workers, Tumba Muerta Road, Panama (W. M. Wheeler) (LACM, MCZC) [Examined] Syn. nov. Pseudomyrma sericea var. acaciorum Enzmann 1 945 :90. Syntype workers, Tumba Muerta Road, Panama (W. M. Wheeler) (MCZC) [Examined] [Objective synonym of Pseudomyrma sericea var. acaciarum Wheeler; Brown 1949:43]. Pseudomyrmex sericeus ita (Forel); Kempf 1972:223. Worker diagnosis. — A medium-sized member (HW ca. 0.75-0.98) of the P. sericeus group, with large elongate eyes (REL 0.65), convex median clypeal lobe, subcontiguous frontal carinae (MFC 0.02), and palp formula of 6,4. Head longer than broad (CI 0.85). Basal face of propodeum shorter than declivitous face and meeting the latter at an angle. Petiole short, high (PLI > 1.00), with sharp dorsolateral margins; in profile anterior and dorsal faces of petiole weakly differentiated, rounding sharply into the vertical posterior face (Fig. 2). Body with fine punctulate-coriarious sculpture, opaque. Standing pilosity very sparse; a pair of stout setae present on the pronotal humeri, petiole, and postpetiole. Dark brown-black, with lighter brown maculation variably present on the pronotum, petiole, postpetiole, fronto-clypeal complex, and appendages. Taxonomic comments. — This is one of several species originally described as "varieties" of P. sericeus (Mayr). Workers of P. ita can be distin- guished from those of P. sericeus by the angulate shape of their petiole, especially in lateral view (Fig. 2 ); the petiole of P. sericeus is subtriangular in profile, with more gently rounded edges. Distribution and biology. — P. ita occurs from Mexico to Colombia, and typically inhabits dead twigs or branches of various woody plants. It has been collected from thorns of Acacia cornigera in Mexico and A. collinsii in Costa Rica and Panama. Pseudomyrmex kuenckeli (Emery (Fig. 3) 890) Pseudomyrma kuenckeli Emery 1890:62. Syntype workers, queens, Alajuela, Costa Rica (A. Alfaro) (MCSN) [Examined]. Pseudomyrma kuenckeli var. dichroa Forel 1 904:4 1 . Syntype workers, Dibulla, Colombia (A. Forel) (AMNH, BMNH, MCSN, MHNG, NHMB, USNM) [Examined] [Synonymy by Kempf 1961:402). Pseudomyrma kuenckeli var. bierigi Santschi 1932:41 2. Holotype worker, Juan Diaz, Panama (A. Bierig) (NHMB) [Examined] [Synonymy by Kempf 1961:402]. Pseudomyrma crenulata Enzmann 1945:84. Holo- type worker, "Guemavaca", Mexico (not in MCZC) [Not examined; but other P. kuenckeli workers in the MCZC from Cuernavaca, Mexico (Wheeler) evidently represent the source series] [Synonymy by Kempf 1961:402]. Pseudomyrmex kuenckeli (Emery); Kusnezov 1953:214. Volume 2, Number 1, 1993 159 Worker diagnosis. — A member of the P. victims group, easily recognized by the shiny broad head (CI 1.12), short eyes (REL 0.46), flattened mesosoma, blocky petiole, and abundant pilosity (Fig. 3). For further description see Kempf (1961:402). Distribution and biology. — This is a widely distributed but generally uncommon species, found from Mexico to Argentina and Brazil. P. kuenckeli appears to have a preference for nesting in large dead branches, in somewhat open or seasonally dry forest. Its association with ant acacias is sporadic at best and based upon two records from Costa Rica: Emery (1891:168) reported a single specimen col- lected by Alfaro from a swollen-thorn acacia, and Menozzi (1927b) recorded a collection by H. Schmidt from Acacia "spadicigera"' (probably a misidentification of A. collinsii) near San Jose. Pseudomyrmex nigropilosus (Emery 1890) (Fig. 7) Taxonomic comments. — Among the P.w/ttfo/?n77H 0.20 mm) and curved. Color varying from concolorous orange-brown to bicolored orange and black to (western Mexico) predominantly black with orange mottling on the head, mesosoma, and appendages. Pseudomyrmex opaciceps Ward, sp. nov. (Fig. 5) Holotype worker.— GUATEMALA Retalhuleu: Puente Samala, 3.8 mi. NE San Felipe, 24.vii. 1 966, D. H. Janzen W006724966 (LACM). HW 1 .43, HL 1 .42, EL 0.85, PL 0.89. PH 0.39. Paratypes, — Series of 1 1 workers with same data as holotype; large series of ca. 60 workers and 10 males with the same locality and collector as holotype but the following dates and collection numbers: 18.vii.l966M0027 18966 (possibly mis- labelled - see below), 18.vii.1966 W0027 18966, 18.vii.1966 W004718966, 18.vii.1966 W0057 18966 (possibly mis-labelled - see below), 23.vii.1966 W002723966, 24.vii.1966 WOO 1724966, 24.vii.1966 W003724966 (BMNH, LACM, MCZC, MZSP, PSWC, UCDC, USNM). Additional non-type material. — Series of work- ers, queens, and males from six additional locali- ties. MEXICO Chiapas: 94.5 mi. SE Tonola (D. H. Janzen ). GUATEMALA Retalhuleu: 2 mi. N Puente Samala, 3.8 mi. NE San Felipe (D. H. Janzen); 3 mi. N Puente Samala. 3.8 mi. NE San Felipe (D. H. Janzen); 5 mi. W Retalhuleu, Hwy. CA-2 at Rio Nil 160 Journal of Hymenoptera Research (D. H. Janzen); Guatemala: Ciudad de Guatemala (D. H. Janzen). EL SALVADOR La Libertad: Quezaltepeque (M. Irwin & D. Cavagnaro) (LACM, MCZC, PSWC). Worker measurements (n=14). — HL 1 .30- 1 .42, HW 1.33-1.43, MFC 0.040-0.058, CI 0.99-1.04, REL 0.57-0.61, REL2 0.56-0.61, OOI 0.14-0.68, VI 0.65-0.71, FCI 0.029-0.042, SI 0.46-0.50, SI2 0.77-0.88, FI 0.36-0.39, PDI 1 . 1 2- 1 .37. MPI 0.059- 0.076, NI 0.65-0.70, PLI 0.42-0.47, PWI 0.38-0.43, PPWI 0.92-1.16. Worker diagnosis. — With the traits of the P. gracilis group ( see couplet 6 of key ) and the follow- ing more specific features. Head about as broad as long; anterior margin of median clypeal lobe straight to weakly convex; pronotum with blunt dorsolat- eral margination; mesonotum more steeply inclined than basal face of propodeum; petiole long and slender (see PLI and PWI values) with a distinct anterior peduncle (Fig. 6); head densely punctulate- coriarious and matte; standing pilosity abundant, pale silvery-white, not black. Color: head and mesosoma dark brown to black, mandibles and appendages lighter brown; petiole, postpetiole and gaster a contrasting pale luteous brown or orange- brown. Portions of the fronto-clypeal complex, malar area, and mandibles may also be luteous brown. Taxonomic comments. — This species is distin- guished from the closely related and sympatric P. gracilis by a modest but consistent difference in head sculpture. In workers and queens of P. opaciceps the punctulate-coriarious sculpture and associated dense pubescence obscure the sheen of the head, producing a matte appearance under soft light, while in P. gracilis the head remains at least weakly shining. In addition the workers and queens of P. opaciceps average smaller in size than those of P. gracilis and they have a more slender petiole ( PLI < 0.48; see Figs. 5, 6, 53). Finally, P. opaciceps has a distinctive and largely invariant color pattern: the pale yellow or orange-brown petiole, postpetiole and gaster contrast with the much darker head and mesosoma. This is not observed in Central Ameri- can P. gracilis, although a similar color pattern occurs in some Colombian populations of P. gracilis, and it also seen in some individuals of the more distantly related South American species P. venustus (F.Smith). Among the P. opaciceps paratypes in LACM, the pinned specimens with Janzen collection num- bers M0027 1 8966 and W0057 1 8966 appear to have been mis-labelled. In the Janzen alcohol collection samples M0027 18966 and W0057 18966 contain colony series of two quite different species (in the P. ferrugineus and P. pallidus groups, respectively ); but there are two other alcohol samples from the same date and locality (W0027 18966 and W0047 18966) which are of P. opaciceps. I con- clude that a frame-shift occurred in the process of labelling the pinned series of specimens, producing the labelling error (this has happened to a substan- tial number of P. ferrugineus group collections - see "Materials and Methods" section). The remain- ing paratype (and non-type) material of P. opaciceps appears to be correctly labelled. Biology. — P. opaciceps is evidently a generalist twig-nesting Pseudomyrmex, but Janzen also col- lected it from an Acacia cornigera tree overgrown by vines and unoccupied by the P. ferrugineus group (5 mi. W Retalhuleu, Guatemala, collection numbers M0 107 14966- A and M010716966-D). Pseudomyrmex reconditus Ward, sp. nov. (Fig. 8) Holotype worker.— NICARAGUA, Madriz: 2.0 mi.SHonduranborder,Hwy 1, 840m, 29. vii. 1967, mi. 8207.2, D. H. Janzen, ex Acacia collinsii (LACM). Paratypes. — One worker, one dealate queen, same data as holotype (LACM). Holotype and paratype worker measurements. — HL 1 .54, 1 .44, HW 1 .54, 1 .47, MFC 0.07 1 , 0.056, EL 0.93, 0.86, PL 0.88, 0.78, PH 0.57. 0.47. CI 1.00, 1.02, OI 0.52. 0.52, REL 0.61, 0.59, REL2 0.61, 0.58, OOI -0.01, -0.01, VI 0.73. 0.71, FCI 0.046, 0.038, SI 0.47, 0.47, FI 0.44, 0.39, PDI 1 .2 1 , 1.12, MPI 0.067, 0.061, NI 0.62, 0.64, PLI 0.64, 0.60, PWI 0.57, 0.53, PPWI 1.40, 1.25. Paratype queen measurements. — HL 1 .79, H W 1.66, MFC 0.065, EL 1.02, PL 1.21, PH 0.75, CI 0.92, OI 0.5 1 , REL 0.57, REL2 0.62, OOI 0.22, VI 0.79, FCI 0.039, SI 0.45, FI 0.46, NI 0.6 1 . PLI 0.62, PWI 0.61, PPWI 1.53. Worker diagnosis. — With the traits of the P. Volume 2, Number 1, 1993 161 gracilis group ( see couplet 6 of key ) and the follow- ing more specific features. Head as broad as long; anterior margin of median clypeal lobe slightly convex, rounded laterally; pronotum with blunt dorsolateral marginatum; mesonotum more steeply inclined than basal face of propodeum; petiole of moderate length, high (PLI 0.60-0.64), with a dis- tinct anterior peduncle but without a well devel- oped anteroventral tooth (Figs. 8, 53), and lacking shaip dorsolateral margination; postpetiole notably broader than long. Mandibles weakly striolate, sublucid, becoming shagreened basally; head and mesosoma densely but finely punctulate-coriarious to coriarious-imbricate, subopaque; petiole, postpetiole, and gaster with fine piligerous punc- tures, obscured from view by the associated pubes- cence. Standing pilosity only moderately dense but with some apparent loss due to abrasion of the type specimens; hairs mostly black, not silvery-white, present on the head, mesosoma dorsum, petiole, and postpetiole; at least some moderately long (0.23-0.27 mm) hairs on the propodeum and peti- ole; one or two short hairs present on the outer faces of the meso- and meta-tibiae, the others possibly worn off; fine appressed golden pubescence present on most of the body. Head and mesosoma black, gaster dark brown, petiole and postpetiole orange; appendages brown, with orange flecking on the legs. Taxonomic comments. This species is known only from the types. It is readily distinguished from all other acacia-associated species in the P. gracilis group by the combination of broad head (see CI values), robust petiole (PLI 0.60-0.64), and black pilosity. P. reconditus is similar to an undescribed Pseudomyrmex species collected from Tachigali in northern Peru (P. sp. PSW-35) but the latter has a shorter petiole, more extensive silvery-white pilos- ity and pubescence, and is all black in color. Biology. — The type collection from Acacia collinsii is the only record. A single worker of P. nigropilosus occurred in the same alcohol vial as the workers and queen of P. reconditus. It remains to be confirmed that P. reconditus is confined to nesting in swollen-thorn acacias. Pseudomyrmex simulans Kempf 1958:459. Holo- type worker, Tumba Muerta Road. Panama ( W. M. Wheeler) (MCZC) [Examined]. Worker diagnosis. — With the traits of the P. gracilis group (see couplet 6 of key ) and the follow- ing more specific features. Head longer than broad (CI 0.86-0.90); anterior margin of median clypeal lobe straight to broadly convex, rounded laterally; pronotum with sharp dorsolateral margination; mesonotum more steeply inclined than basal face of propodeum; petiole relatively short and high (PLI 0.61-0.66), with a distinct anterior peduncle (Figs. 9, 53), and with moderate dorsolateral mar- gination; head and mesosoma finely punctulate- coriarious to coriarious-imbricate, subopaque; standing pilosity rather short, pale and inconspicu- ous, present on the mesosoma dorsum and ( usually ) outer surfaces of the tibiae, but sometimes lacking or worn off on the latter; fine appressed pubescence on most of body; dark brown-black in color, distal portions of appendages lighter; mandibles luteous. Taxonomic comments. — This curious species bears a superficial resemblance to the obligate acacia-ants (P. ferrugineus group), although its affinities to other P. gracilis group species are clear from eye size, pilosity, palp formula, mesosomal structure, and male genitalia. P. simulans can be recognized by the combination of elongate eyes (REL 0.52-0.55), short petiole (PLI 0.61-0.66). short inconspicuous pilosity, and black color. Distribution and biology. — P. simulans is known only from a few collections, all from swollen-thorn acacias (A. collinsii), in Panama (Canal Zone and the provinces of Veraguas, Los Santos and Panama). Nothing has been published about its nesting biol- ogy or behavior, but Janzen's field notes indicate that the workers are more timid than those of the P. ferrugineus group. One might surmise that its hab- its are similar to those of P. nigropilosus, although the two species do not appear to be one another's closest relatives (Ward 1991 ). Pseudomyrmex subtilissiinus ( Emery 1 890) Pseudomyrmex simulans Kempf 1958 (Fig. 9) Pseudomyrma subtilissima Emery 1 890:65. Lecto- type worker, Alajuela, Costa Rica (Alfaro) 162 Journal of Hymenoptera Research (MCSN) [Examined]. Pseudomyrmex subtilissimus (Emery 1890); Kempt" 1972:224. Worker diagnosis. — A member of the P. subtilissimus group, and immediately distinguish- able from all other acacia-associated Pseudomyrmex by its small size (HW < 0.60), elongate head (CI < 0.66), apedunculate petiole, and scarcity of stand- ing pilosity. See Ward (1989:432) for further dis- cussion of this species. Distribution and biology. — P. subtilissimus has been collected only in Nicaragua and Costa Rica. What little is known about its biology suggests that it is a timid, non-protective species living in the thorns of Acacia plants occupied by (declining?) colonies of P. flavicornis. PHYLOGENY AND BIOGEOGRAPHY OF THE OBLIGATE ACACIA-ANTS The 47-character data set used for cladistic analy- sis of the P.ferrugineus group is given in Table 2. Implicit enumeration by Hennig86. using the ie* command, yielded a single most parsimonious tree of length 73, consistency index 0.86 (0.84 exclud- ing autapomorphies of ingroup species) (Fig. 73). This tree has an unresolved bifurcation involving five Pseudomyrmex species: ferrugineus,janzeni, and (flavicornis + {mixtecus + veneficus)). These five species together constitute what may be termed the P.ferrugineus complex. It is allied to the pair of sister species, P. spinicola and P. satanicus. The sister group of these seven species is the isolated and autapomorphous P. peperi. Finally, P. nigrocinctus and P. particeps make up a basal pair of species with relatively unspecialized morphol- ogy- Separate analyses of worker-, queen-, and male- based data sets produced trees in substantial agree- ment with these findings and largely congruent with one another (Figs. 74-76). This indicates that some confidence can be attached to the main fea- tures of the cladogram, and that homoplasy in worker and queen morphology — possibly due to parallel selection pressures during diffuse coevolu- tion of the ant/acacia interaction (see below) — has not been so rampant as to obscure all evidence of relationship, since both castes point to a cladistic pattern similar to that derived from male morphol- ogy (primarily male genital characters). Disagree- ment revolves around the position of taxa within the P.ferrugineus complex. Worker morphology sug- gests that P. mixtecus is more closely related to P. flavicornis than to P. veneficus. The male character set supports a (P. mixtecus + P. veneficus) pairing and is uninformative about other relationships within the P.ferrugineus complex. The queen-based tree is identical in topology to that based on all characters, i.e. it supports (P. flavicornis + {P. mixtecus + P. veneficus)) but does not resolve relationships among P.ferrugineus, P.janzeni, and the foregoing trio. The inferred phylogeny of the P. ferrugineus group (Fig. 73) suggests that speciation has oc- curred primarily as a consequence of geographical isolation. Of the three pairs of sister species, two (P. nigrocinctus + P. particeps, P. mixtecus + P. veneficus) are composed of allopatric species ( Figs. 69, 72), while the ranges of the third pair (P. spinicola and P. satanicus) are more or less con- tiguous ( Fig. 68 ). The trio of species comprising (P. flavicornis + (P. mixtecus + P. veneficus)) also have entirely non-overlapping distributions, and they point to the importance of geographical barriers in southwestern Mexico to speciation in this complex (Fig. 69). This is also indicated by the distributions of P. ferrugineus and P. janzeni, the latter an allopatric isolate in western Mexico (Fig. 70), al- though it should be noted that the cladistic analysis did not confirm a sister group relationship between these two phenetically similar species. At higher levels in the cladogram there is some geographical overlap between taxa, but dispersal has not been so extensive as to obliterate all evidence of vicariance. Within the P. ferrugineus complex, forexample, P. flavicornis and relatives are largely confined to the Pacific slopes of Mesoamerica in contrast to the more eastern distribution of P. ferrugineus (Figs. 69-70). The P.ferrugineus complex itself is centred in northern Central America, with only one species ( P. flavicornis) occurring south of Honduras, as far as Costa Rica in this case, while its sister group (P. spinicola and P. satanicus) occurs primarily south of Honduras and extends all the way to northern Colombia (Fig. 68). This suggests an historical barrier somewhere in the region of present day Volume 2, Number 1, 1993 163 Honduras or Nicaragua which split these two clades. The most basal divisions within the P.ferrugineus group involve much more extensive geographical overlap, making any historical inferences difficult. The distributions of the species P. peperi and P. nigrocinctus are consistent with an origin and early diversification of the P.ferrugineus group in either northern or central Mesoamerica. The timeframe for this is unknown but presumably occurred prior to the formation of the Panamanian land bridge (i.e. before early Pliocene or late Miocene). Early diver- sification in the group may have been encouraged by the presence of an island archipelago in the region (Donnelly 1992). Finally, we come to the question of whether the phylogenies of the acacia-ants and their host aca- cias are congruent. A phylogeny of the swollen- thorn acacias is not available but Janzen's ( 1974) revision contains some relevant information. Janzen ( 1974) concluded that the Central American swol- len-thorn acacias are polyphyletic. i.e. that my rmecophy tism arose more than once or that non- myrmecophytic acacia species independently ac- quired myrmecophytic traits through hybridiza- tion. He also noted (Janzen 1966) that individual species of acacia can be associated with more than one Pseudomyrmex species and vice versa. None of this leads one to expect a pattern of co-speciation, and mapping known host associations on the Pseudomyrmex cladogram (Fig. 73) confirms the opportunistic nature of the interaction. It seems that most species in the Pseudomyrmex ferrugineus group occupy any swollen-thorn acacia species available to them. On the other hand, the possibility of locally non-random associations between ants and available plants, perhaps mediated by compe- tition, deserves investigation. Three species of acacia-ants, P. janzeni, P. particeps and P. satanicus, are confined to a single acacia species (A. hindsii, A. allenii and A. melanoceras, respectively), the former { P. janzeni) almost certainly because of its limited geographical distribution but the last two because of their appar- ent specialization on the acacia or the forest habitat to which it is restricted. Populations of other swol- len-thorn acacia species occur within the probable dispersal ranges of alate queens of P. particeps and P. satanicus but are apparently not colonized. These two host-specific Pseudomyrmex have the smallest ranges of any members of the P.ferrugineus group and are clearly the most endangered. CONCLUDING REMARKS Table 2. Data set used for cladistic analysis of me Pseudomyrmex ferrugineus group. P. fervidus served as outgroup (see text)."?" signifies polymorphism or ambiguity in expression of the character state. Characters 12, 13 and 1 6 were considered unordered. 1 11 21 31 41 fen'idus 0000000000 ??00000001 ?000?00000 0000000000 00000?0 nigrocinctus 0001000001 1021000010 0011001000 0001110010 1001101 particeps 0001000001 1021000011 0010001100 0001110010 1001101 peperi 0011001121 2210020011 0011011001 0002100111 1112212 spinicola 1100101111 010010001? 11 10701 110 0112100011 1212221 satanicus 1110111111 0100100011 1210201110 0112100011 1212221 ferrugineus 0000001111 0100001011 1110201010 0102101111 1222221 janzeni 0000001111 0100001010 1110201010 0102101111 1222221 fiavicornis 0000001111 0100011012 1110201010 0102101111 1222221 mixtecus 0000001 1 1 1 0100011012 11111 11010 0102101121 1222221 veneficus 0000001111 0100001112 1111111010 0102101121 1222221 164 Journal of Hymenoptera Research 73 1 2 5 15 28 33 | | I I I II II " 17 37 38 43 Mil 16 20 =H= ch cl cr ge gl hi — =■ spinicola al cl cr xerrugineus ch cl co cr ge gl hi ma sp janzeni hi = flavicornis cl cr hi lixtecus cl hi veneficus cl hi 74 75 76 worker characters (length 29 cl 0.89) queen characters (length 33 ci 0.75) male characters (length 28 ci 0.96) Figs 73-76. Phylogenetic relationships of the obligate acacia-ants, Pseudomyrmex ferrugineus group. 73: cladogram based on the entire 47-character data set (Table 2). with character state changes indicated and with host plant associations listed for each species. Solid bars: unique forward changes; hatched bars: homoplasious forward changes: open bars: reversals. There are alternative, equally parsimonious reconstructions of character state change for characters 4, 12, 1 6, 38 and 46. By reference to other Pseudomyrmex species, most changes occurring between the outgroup (P.fervidus) and the ingroup (i.e. changes in characters 10, 19, 23. ..47) are probably synapomorphies of the latter, but one character state (27.0) appears to be a derived feature of P. fervidus. The following abbreviations are used for host plants: al = Acacia allenii, ch = A. chiapensis, cl = Acacia collinsii, co = A. cooki and A. janzenii, cr = A. cornigera, ge = A. gentlei, gl = A. globulifera, hi = A.hindsii, ma = A. mayana, me = A. melanoceras, sp = A. sphaerocephala. 74-76: cladograms based on the worker, queen and male character sets, respectively. Volume 2, Number 1, 1993 165 This systematic study of Pseudomyrmex ants associated with swollen-thorn acacias in Central America demonstrates that the primary group of obligate acacia-ants (the P. ferrugineus group) is monophyletic and comprises 10 species. Four addi- tional unrelated Pseudomyrmex species, from two other species groups, have become secondary spe- cialists on the acacias. These latter species appear to be parasites or commensals but little is known about their biology (except P. nigropilosus). These 14 specialists are joined by at least six generalist twig-nesting Pseudomyrmex which occasionally colonize acacia thorns. The well known mutualism between ants and Central American acacias applies with certainty only to members of the P. ferrugineus group and their associated plants. Within this group experi- mental evidence of a mutualism is available only for the P. ferrugineus x A. cornigera interaction (Janzen 1966, 1967b). although the biology and behavior of the other nine species of ants suggest that they also provide important protection to their host acacias under most conditions. Cladistic analy- sis of the P. ferrugineus group, coupled with a consideration of host plant associations, indicates a pattern of diffuse coevolution, not one-on-one cospeciation (see also Janzen 1966). It seems likely that the original obligate acacia-ant (the common ancestor of the P. ferrugineus group) underwent coevolution with its acacia host, but since then speciation and diversification of the two groups have been decoupled — the swollen-thorn acacias are apparently even polyphyletic (Janzen 1974) — and there has been much opportunistic pairing of ants and plants. Such liberal sharing of partners has presumably made the association susceptible to invasion by other Pseudomyrmex and Acacia lin- eages. At the same time the key features of the system — absolute dependence of ants in the P. ferrugineus group on acacia plants, the reliance of at least some (probably most) of the swollen-thorn acacia spe- cies on ants for normal growth and reproduction, and the suite of mutually beneficial traits exhibited by both partners — mark this as one of the more impressive insect/plant mutualisms known. ACKNOWLEDGMENTS I thank the following persons for access to collec- tions under their care: J. Newlin (ANSP). B. Bolton (BMNH). M. A. Tenorio (CASC), H. A. Hespenheide (CHAH), R. Ayala (EBCC). F. Fernandez (FFIC), D. Quintero Arias (GBFM), A. Solis (INBC ). J. T. Longino (JTLC), R. R. Snelling (LACM; also old loans to D. H. Janzen from AMNH. CISC. CUIC, GCWC, INHS, KSUC. MCZC, SEMC, UCDC. UCRC and USNM. now returned to their original locations), R. Poggi (MCSN).S.Cover(MCZC),C.Besuchet(MHNG).J.C. Weulersse (MNHN), C. R. F. Brandao (MZSP). M. Brancucci (NHMB), M. Fisher (NHMV). D. R. Smith (USNM).W.P.MacKay(WPMC),F.Koch(ZMHB),0. Lumholdt (ZMUC), D. R. Abraham (ZMUH) and E. Diller (ZSMC). Special tribute should be paid to Dan Janzen whose prodigious efforts in the field yielded a collection of acacia-ants unprecedented in size and scope, together with much valuable biological information. 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M., Jonsson, B., Lindem, T., Magniisson. K. P., Malmquist, H. J., Sigurjonsdottir. H.. Skiilason, S., Snorrason, S. S. 1992. The arctic charr Salvelinus alpinus in Thingvallavatn. Oikos 64:305-35 1 . Santschi. F. 1922. Myrmicines. dolichoderines et autres formicides neotropiques. Bulletin de la Societe Vaudoise des Sciences Naturelles 54:345-378. Santschi. F. 1931. Fourmis de Cuba et de Panama. Revista de Entomologia, Rio de Janeiro 1:265-282. Santschi. F. 1932. Quelques fourmis inedites de 1' Amerique centrale et Cuba. Revista de Entomologia, Rio de Janeiro 2:410-414. Skwarra. E. 1 934a. Okologie der Lebensgemeinschaften mexikanischer Ameisenplanfzen. Zeitschrift fur Morphologie und Okologie der Tiere 29:306-373. Skwarra, E. 1934b. Okologische Studien iiber Ameisen und Ameisenpflanzen in Mexiko. Konigsberg: pub- lished by author (printer: R. Leupold). 153 pp. Smith, F. 1855. Descriptions of some species of Brazil- ian ants belonging to the genera Pseudomyrma, Eciton and Myrmica (with observations on their economy by Mr. H. W. Bates). Transactions of the Royal Entomological Society of London (2)3: 156-169. Smith, F. 1 860. Catalogue of hymenopterous insects collected by Mr. A. R. Wallace in the islands of Bachian, Kaisaa, Amboyna, Gilolo. and at Dory in New Guinea. Journal of the Proceedings of the Linnaean Society of London, Zoology 5( 17b)(suppl. to vol. 4):93-143. Smith. F. 1 862. Descriptions of new species of aculeate Hymenoptera, collected at Panama by R. W. Stretch, Esq., with a list of described species, and the various localities where they have previously occurred. Trans- actions of the Royal Entomological Society of Lon- don (3)1:29-44. Smith, F. 1877. Descriptions of new species of the genera Pseudomyrma and Tetraponera, belonging to the family Myrmicidae. Transactions of the Royal Entomological Society of London 1877:57-72. Smith. M. R. 1952. The correct name for the group of ants formerly known as Pseudomyrma (Hy- menoptera). Proceedings of the Entomological Soci- ety of Washington 54:97-98. Stitz, H. 1933. Neue Ameisen des Hamburger Museums (Hym. Form.). Mitteilungen der Deutschen Entomologischen Gesellscha.fi 4:67-75. Ward. P. S. 1985. The Nearctic species of the genus Pseudomyrmex (Hymenoptera: Formicidae). Quaestiones Entomologicae 21:209-246. Ward, P. S. 1989. Systematic studies on pseudomyrmecine ants: revision of the Pseudomyrmex oculatus and P. subtilissimus species groups, with taxonomic comments on other species. Quaestiones Entomologicae 25:393-468. Ward, P. S. 1991. Phylogenetic analysis of pseudomyrmecine ants associated with domatia-bear- ing plants. Pp. 335-352 in: Huxley. C. R., Cutler, D. F. (eds.) Ant-plant interactions. Oxford: Oxford University Press, xviii + 601 pp. Wasmann. E. 1915. Eine neue Pseudomyrma aus der Ochsenhorndornakazie in Mexiko. mit Bemerkungen iiber Ameisen in Akaziendornen und ihre Gaste. Ein kritischer Beitrag zur Pflanzen-Myrmekophilie. 168 Journal of Hymenoptera Research Tijdschrift voor Entomologie 58:296-325. Wasmann. E. 1 9 1 6. Nachtrag zu "Eine neue Pseudomyrma aus der Ochsenhorndornakazie in Mexiko". Tijdschrift voor Entomologie 58(suppl.): 125-131. Weidner, H. 1972. Die Entomologischen Sammlungen des Zoologischen Instituts und Zoologischen Muse- ums der Universitat Hamburg. Mitteihmgen aits den Hamburgischen Zoologischen Museum und Institut 68:107-134. Wheeler, G. C, Wheeler, J. 1956. The ant larvae of the subfamily Pseudomyrmecinae (Hymenoptera: Formicidae). Annals of the Entomological Society of America 49:374-398. Wheeler, W. M. 1913. Observations on the Central American acacia ants. Pp. 109-139 in: Jordan, K., Eltringham, H. (eds.) 2nd International Congress of Entomology, Oxford, August 1912. Volume II. Trans- actions. London: Hazell, Watson & Viney, Ltd., 489 pp. Wheeler, W. M. 1 92 1 . A new case of parabiosis and the "ant gardens" of British Guiana. Ecology 2:89-103. Wheeler, W. M. 1942. Studies of Neotropical ant-plants and their ants. Bulletin of the Museum of Compara- tive Zoology 90: 1-262. Young, B. E., Kaspari, M.. Martin. T. E. 1990. Species- specific nest site selection by birds in ant-acacia trees. Biotropica 22:310-315. J. HYM. RES. 2(1), 1993 pp. 169- 182 Species of Orasema parasitic on the Solenopsis saevissima-comp\ex in South America (Hymenoptera: Eucharitidae, Formicidae) J.M. Heraty, D.P. Wojcik and D.P. Jouvenaz (JMH) Department of Biology, Carleton University. Ottawa. Ontario, Canada. K1S 5B6; (DPW. DPJ) Medical and Veterinary Entomology Research Laboratory, USDA. ARS. P.O. Box 14565, Gainesville. FL, USA 32604. (DPJ, retired January 1992). Abstract. — The South American species of the Orasema xanthopus-group are revised. The five species included are O. pireta n. sp„ O. salebrosa n. sp., O. simplex n. sp., O. worcesteri (Girault) (O. doellojuradoi Gemignani as new synonym), and O. xanthopus (Cameron) (Eucharomorpha paraguayensis Girault and O. crassa DeSantis as new synonyms). Immature stages are described for three of the species. Ant hosts include Pheidole radoszkowskii Mayr, Solenopsis invicta Buren and Solenopsis richteri Forel (all Myrmicinae). The life history of O. xanthopus is discussed. Several reports have mentioned a species of Orasema (Hymenoptera: Eucharitidae) that is a parasite of fire ants in South America (Silveira- Guido et al. 1964; Williams and Whitcomb 1973; Williams 1980; Wojcik 1988, 1989; Wojcik et al. 1987). These parasites are dominant among the insect parasites of fire ants in Brazil and, in 1585 collections of colonies from Brazil, represented about 80% of all myrmecophilous arthropods re- covered (Wojcik et al. 1987). Parasites of ants in the Solenopsis saevissima-complex, revised by Trager 1 99 1 , all belong to a single species group of Orasema that occurs over the same range as the host complex in South America. Almost all species of Orasema are parasites of Myrmicinae (Formicidae) and are known to para- sitize ants in the genera Pheidole, Solenopsis, Tetramorium and Wasmannia (Heraty in press-b). Females deposit a single egg into a chamber formed in leaf tissue using a specialized ovipositor (Johnson et al. 1986, Heraty in press-a,b). The first-instar larvae reach the ant nest by some means of phoretic behaviour, either through attachment to an ant or to an intermediate insect host, and then parasitize the host larva (Johnson et al. 1 986, Heraty in press-a,b). Development is completed on the pupal stage of the host. Collections of colonies of Solenopsis invicta Buren from Bolivia and Brazil, and Solenopsis richteri Forel from Argentina, have permitted for study of the immature stages of three species, and these are described here. The life histories and structures of the immature stages do not differ greatly from those first described by Wheeler ( 1 907 ) for other species of Ora.Yf/Hrt; however, differences in structure at the species level do exist. Within this species-group of Orasema, the oviposition habits, plant host, and behavior of planidia outside of the host colony remain largely unknown. This paper provides diagnoses and correct nomenclature, and summarizes the distribution and biology for spe- cies of Orasema that are known to be parasites of fire ants of South America. The terms used in the descriptions follow Heraty ( 1 989, in press-a). Museum acronyms are described in the acknowledgements. Orasema xanthopus-group The five species included in the xanthopus- group have the following combination of character states: funicle 8-segmented, scape yellowish brown, face and mesoscutum reticulate, and axillular sul- cus at least partially discernible. The hind femora is dark brown to black medially in all included spe- cies, but sometimes not in all specimens of each species; however, this combination of a darkened femora with the other character states listed above is unique among Orasema. This group of species may be paraphyletic with respect to a monophy letic group that includes Orasema aenea (Gahan), which is distinguished by: mesosomal dorsum coarsely 170 Journal of Hymenoptera Research rugose, axillular sulcus absent, and femora always completely yellowish brown. Group Description [diagnostic characters in bold type]. Colour of head, mesosoma, coxae and petiole usually dark (rarely bright) olive- or bluish-green, sometimes with red or purple iridescent patches; gaster dark brown with bluish green reflections; scape yellow- ish brown, with following segments, including pedicel and anellus, brown; all femora usually at least slightly darker medially with apicies yel- lowish brown, rarely completely yellowish brown, tibiae yellowish brown. Wings hyaline, veins light brown. Head 1 .2- 1 .5X as broad as high; occiput broadly emarginate in dorsal view. Face, including scrobal depression, finely reticulate; scrobes shallow and narrowed medially (Figs. 1-5), median ocellus par- tially included; toruli separated by distance equal to their diameter; occiput aciculate. dorsal margin without carina but angle sharp at vertex. Eyes bare. Clypeus transverse and distinctly shorter than supraclypeal area, apical margin of clypeus nearly straight, lateral margin deeply impressed at tentorial pit; frontogenal sulcus meeting torulus at outer margin. Malar depression weakly impressed adja- cent to oral fossa. Labrum with 4 long digits. Mandibles 3/2 dentate; maxillary palpus with 3 segments, labial palpus with 2 or 3 segments. An- tenna with 12 segments; anellus distinct; funicle in both sexes with 8 segments; clava subconical and rounded apically. Mesosoma with midlobe of mesoscutum re- ticulate, and side lobe with similar but weaker sculpture dorsally . Notaulus and scutoscutellar sul- cus deeply impressed and crenulate. Axillular sul- cus at least weakly indicated. Disc of propodeum evenly sculptured. Transepimeral sulcus distinct; mesepisternum evenly reticulate except for ante- rior and ventral regions. Prepectus triangular. Proepisternum weakly sculptured. Hind coxa re- ticulate dorsally. Fore wing 2.2-2.6X as long as broad and broadly rounded apically; basal area bare except for setae along impression of cubital vein, costal cell pilose, speculum present and closed basally, disc pilose and hyaline with promi- nent marginal fringe; stigmal vein angled slightly towards apex of wing; postmarginal vein 2-4X as long as stigmal vein. Petiole of female 0.8- 1 .OX as long as hind coxa, that of male 1 .0- 1 .4X as long as hind coxa; petiole smooth, weakly rugose (wrinkled) or finely re- ticulate, cylindrical with basal flange usually weak. First gastral sternite (Ms2) with transverse crenu- late sulcus. Ovipositor expanded subapically; first valvula with lateral line of 4 to 10 prominent teeth distal to subapical ridge; second valvula broad with 7-9 lateral teeth, and with or without weak trans- verse ridges. Genitalia typical for genus; basiparamere robust and broad, paramere short and well sclerotized, aedeagus subtruncate. KEY TO SPECIES OF THE ORASEMA XANTHOPUS-GROUP 1. Petiole finely and strongly reticulate worcesteri Girault -Petiole smooth, weakly rugose, or carinate (if present, rugae smooth and hardly raised above surface) 2 2. Petiole of female 2.6-3. 1 X as long as broad, completely smooth with 1 or 2 longitudinal carinaebasally ; mesepimeron and callus smooth; callus with prominent nib (male unknown) ...pireta Heraty, n. sp. — Petiole of female 1.3-2.0X as long as broad, petiole of both sexes weakly rugose or carinate; mesepimeron and callus usually with prominent sculpture, callus without nib 3 3. Scutellum scabrous dorsally; callus rugulose and with 10-12 prominent hairs salebrosa Heraty. n. sp. — Scutellum finely reticulate dorsally; callus coriaceous or mostly smooth and with 2-4 minute hairs or bare 4 4. Axillular sulcus indistinct, at most vaguely indicated by change in sculpture; dorsal margin of scutellum flat in profile; femora of both sexes mostly dark brown to black ...simplex Heraty, n. sp. - Axillular sulcus distinct and foveate, at least anteriorly; dorsal margin of scutellum rounded in profile; femora of female weakly to strongly darkened medially, that of male weakly darkened or completely yellowish brown xanthopus (Cameron) Volume 2, Number 1, 1993 171 Orasema pireta Heraty, new species (Fig. 1) Holotype. female "PARAGUAY: Pirareta, 26.xii.1971, L.E. Pena." Deposited in CNC. Paratopes: PARAGUAY: same data (2 females, CNC; 1 female, USNM); same locality and collec- tor, 23-25.xii.1971 (1 female, CNC). Diagnosis. — Within the xanthopus-grovtp, rec- ognized by: petiole narrow and elongate, 2.6-3. IX as long as broad, and mostly smooth and shining with at most with few weak longitudinal carinae in basal third; mesepimeron, callus and metepimeron smooth; callus with 2-3 minute setae and with prominent calar nib; femora of female completely yellowish brown or weakly fuscate medially; axillular sulcus strongly impressed. Description of female. — Length, 3.0-3.9 mm. Colour of head and body dark brown with greenish- blue reflections, strongest on head and mesosomal dorsum [may be partially bleached in these speci- mens]. Head 1.3-1.4X as broad as high (Fig. 1 ). Facial sculpture reticulate with interstices hardly raised above surface, intertorular area smooth. Eyes sepa- rated by 1.8X their height. Malar space 0.8-0.9X height of eye. Clypeus and supraclypeal area swol- len medially, clypeus smooth with few small setae. Flagellum 1 .6- 1 .IX height of head; FL2 1 . 1 - 1 .4X as long as broad. Mesosoma with entire dorsum finely reticulate, side lobe ofmesoscutumalutaceous. Disc of scutel- lum slightly longer than broad, flat dorsally (in lateral view), and without median depression; fre- num finely reticulate; frenal line broadly and deeply impressed dorsally, strongly angled to scutellar disc (in lateral view), and reticulate dorsally and glabrous laterally; axillula vertical and smooth or with weak rugosity, axillular sulcus strongly im- pressed and reticulate. Propodeal disc weakly re- ticulate or alutaceous laterally and with broad me- dian areolate depression; callus swollen and smooth, with 2-3 minute hairs dorsally or bare, and with prominent callar nib. Mesepimeron smooth. Fore wing 2.3-2.5X as long as broad. Petiole 1.3-1.5X as long as broad, 0.6-0.8X as long as hind coxa; petiole entirely smooth, some- times with few weak longitudinal carinae in basal third, the basal flange weak. First valvula of ovi- positor with lateral line of 4 to 7 prominent teeth; second valvula with 7 lateral teeth connected by weak transverse ridges. Male. — Unknown. Host and immature stages. — Unknown. Etymology. — Adapted from the name of the type locality. Orasema salebrosa Heraty, new species (Figs. 2, 19) Holotype, female "ARGENTINA: Buenos Aires P., San Carlos de Bolivar, RN-226, 8.iv. 1987, D.P. Wojcik 87-A-407, ex: floated fire ants." Deposited in CNC. Paratypes: ARGENTINA: Buenos Aires Prov.: same data as holotype ( 1 female, CNC); Suipacha, RN-5, km 1 27, 28.x. 1 987, D.P. Wojcik, 87- A-590, ex: floated Solenopsis richteri ( 1 female, 1 male, 4 female pupae, CNC; 1 female, USNM); San Carlos de Bolivar, RN-226, 8.iv. 1 987, D.P. Wojcik, 87-A- 407, ex floated fire ants ( 1 female, CNC). Diagnosis. — Within the .xanthopus-group, both sexes recognized by: side lobe of mesoscutum laterally, and scutellum dorsally, scabrous (rugose with interstices strongly raised and sharp); callus rugose with 10-12 hairs dorsally; femora of both sexes dark brown to black medially; axillular sul- cus strongly impressed. Description of female. — Length, 3.0-3.9 mm. Colour of head and body dark bluish green to almost black, sometimes with strong purple reflec- tions laterally. Head 1.3-1. 4X as broad as high (Fig. 2). Face strongly reticulate, intertorular area transversely strigate. Eyes separated by 1 .8X their height. Malar space 0.8-0.9X height of eye. Clypeus slightly swollen medially and mostly smooth with moder- ately dense fine setae. Flagellum 1 .6- 1 .7X height of head; FL2 1.1-1 .4X as long as broad. Mesosoma with mesoscutum and axilla reticu- late, scutellum rugose or scabrous, with interstices sharp. Disc of scutellum slightly longer than broad, flat dorsally (in lateral view), and with broad me- dian depression; frenum rugose; frenal line strongly impressed and foveate or crenulate dorsally, gla- brous laterally; axillula slightly rounded and rug- 172 Journal of Hymenoptera Research ose, axillular sulcus strongly impressed and fove- ate. Propodeal disc evenly rugose-areolate, without median depression; callus swollen and rugose, with 10-13 hairs dorsally, and without callar nib. Upper mesepimeron swollen and weakly reticulate, lower mesepimeron rugulose. Fore wing (Fig. 5) 2.3- 2.5X as long as broad. Petiole 1.3-1.5X as long as broad, 0.6-0.8X as long as hind coxa; petiole smooth with weak irregu- lar rugae, the basal flange weak. First valvula of ovipositor with lateral line of 8 prominent teeth [second valvula hidden]. Description of male. — Length, 3.1 mm. Eyes separated by 1.8X their height. Malar space 0.8X height of eye. Flagellum slightly longer than in female, 2.2X height of head. Fore wing 2.3X as long as broad. Petiole 2.7X as long as broad, 1.1X as long as hind coxa. Host. — Solenopsis richteriFove\(yiyrm\cmaQ). Immature Stages. — Pupa (Fig. 19). Pupal form is typical for other Orasema and recognized by: two enlarged tubercles over petiole, third enlarged tu- bercle further back over first metasomal tergite; gaster with series of small mid-dorsal tubercles. decreasing in size, over terga II-V; series of small lateral and subventral tubercles or short ridges on terga I- VI. Average length, 3.67 mm (SD=0.48, n=5). Etymology. — From Latin salebrosus for rough, referring to scutellar sculpture. Orasema simplex Heraty, new species (Fig. 3) Holotype, female "ARGENTINA: Buenos Aires P., RN-9, km 231, jet San Nicolas de los Arroyos" "22.x. 1987, D.P. Wojcik 87-A-552-D, ex: floated Solenopsis richteri." Deposited in CNC. Paratypes: ARGENTINA: Buenos Aires: same data(l male, 1 female pupa, CNC; 1 female, 1 male, USNM); Belen de Escobar, RN-9, km 51, 19.x. 1987, D.P. Wojcik, 87-A-483-H, ex: floated Solenopsis richteri (1 female pupa, CNC); La Pampa: 9.ix.l987, N. Puelen (2 females, CNC, NMBA). Diagnosis. — Within the xcinthopus-group, both sexes recognized by: frons and mesosomal dorsum very finely reticulate; scutellum flat dorsally. Figs. 1-5. Head of female. 1,0. pireta. 2, O. salebrosa. 3, O. simplex. 4, O. Worcester). 5. O. xanthopus. Volume 2, Number 1, 1993 axillular sulcus weakly impressed, discernable only by change in sculpture; mesepimeron and callus weakly and finely reticulate, and callus bare; peti- ole smooth with weak and irregular longitudinal rugae; femora of both sexes mostly dark brown or black. Description of female. — Length, 2.7-3.8 mm. Colour of head and body bright green to dark greenish-blue, sometimes with reddish iridescent patches on mesosoma. Head 1.3-1.4X as broad as high (Fig. 3). Face strongly reticulate, intertorular area transversely strigate. Eyes separated by 1 .7-2.0X their height. Malar space 0.8-0.9X height of eye. Clypeus swol- len medially and coriaceous, covered with moder- ately dense fine setae. Flagellum 1 .3- 1 .4X height of head; FL2 1 .3- 1 .7X as long as broad. Mesosoma with entire dorsum finely reticulate. Disc of scutellum slightly longer than broad, flat dorsally (in lateral view), and with weak median depression; frenum reticulate; frenal line not im- pressed dorsally, forming a continuous glabrous band; axillula vertical and longitudinally strigate; axillular sulcus weakly impressed, visible as weak ridge in dorsal view or by change in sculpture. Propodeal disc weakly reticulate or coriaceous, with broad median rugose-areolate depression; cal- lus swollen, weakly reticulate and bare, with weak callar nib. Upper mesepimeron swollen and weakly reticulate, lower mesepimeron mostly smooth. Fore wing 2.1-2.4X as long as broad. Petiole 1.6-2.0X as long as broad, 0.7-0.8X as long as hind coxa; petiole smooth with weak irregu- lar rugae, the basal flange weak. First valvula of ovipositor with lateral line of 9- 1 0 prominent teeth; second valvula with 1 1 lateral teeth connected by weak transverse ridges. Description of male. — Length, 2.7-3.0 mm. Eyes separated by 1.8-1.9X their height. Malar space 0.8X height of eye. Flagellum slightly longer than in female, 1 .6X height of head. Fore wing 2.2-2.4X as long as broad. Petiole 2.8-4. 1 X as long as broad, 1.0-1.4X as long as hind coxa. Host. — Solenopsis richteri Forel (Myrmicinae). Immature Stages. — Pupa. Form is the same as for O. salebrosa, but the lateral tubercles are usu- ally connected by a raised ridge that extends almost 173 to mid-dorsal series (ridge absent in one specimen and complete in another). Length, 3.4 mm. Orasema worcesteri (Girault) (Fig. 4) Eucharomorpha worcesteri Girault, 1 91 3[ 157]: 62- 63. Type locality: Paraguay, San Bernardino. Holotype, female [examined, ZMHB], by origi- nal designation. Orasema Doello-juradoi Gemignani, 1933: 490- 491, figs. 13-14. Type locality, Argentina: Isla Martin Garcia. Holotype, female [examined, NMBA, type no. 31765], by original designa- tion; holotype, paratype and 2 ants mounted on three cards on same pin. The holotype is here assumed to be the top card-mounted specimen. New Synonymy. Orasema worcesteri; combination by Boucek, 1 988: 519. Diagnosis. — Within the .xantliopus-group, fe- male recognized by: femora usually all yellow, sometimes dark brown medially; head subquadrate (Fig. 4); frons and mesosomal dorsum very finely reticulate; scutellum flat dorsally, axillular sulcus weak; mesepimeron and callus weakly and finely reticulate, and callus bare; petiole finely and strongly reticulate with a weak basal flange, petiole shorter than length of hind coxa and 1.4-1.6X as long as broad. This species is similar to O. simplex, but differs by having a finely reticulate petiole, which is a unique character state among species with an 8- segmented funicle and a finely reticulate mesosomal dorsum. Description of female. — Length, 2.8-4.0 mm. Colour of head and body bright green to dark greenish-blue, sometimes with reddish iridescent patches on mesosoma. Head 1.2-1.3X as broad as high (Fig. 4). Face strongly reticulate, intertorular area rugulose. Eyes separated by 1.4-1. 7X their height. Malar space 0.7-0.8X height of eye. Clypeus weakly sculptured or smooth and only slightly rounded medially. Flagellum 1.0-1.4X height of head; FL2 2.0-2.2X as long as broad. Mesosoma with entire dorsum finely reticulate to granulate. Disc of scutellum 1.2X as long as broad, rounded dorsally (in lateral view), and with- 174 Journal of Hymenoptera Research out median furrow; frenum granulate; frenal line impressed, reticulate dorsally and glabrous later- ally; axillula vertical and weakly reticulate or stri- ate, axillular sulcus weakly impressed, marked by difference in sculpture. Propodeal disc finely re- ticulate laterally, sometimes with broad median alveolate channel; callus reticulate and bare, callar nib absent. Upper mesepimeron weakly reticulate, lower mesepimeron smooth to areolate. Fore wing 2.3-2. 5X as long as broad. Petiole 1.4-1.6X as long as broad, 0.7-1. OX as long as hind coxa; petiole strongly reticulate over entire surface, the basal flange weak. First valvula of ovipositor with lateral line of 4 prominent teeth; second valvula broad with 9 lateral teeth connected dorsally by weak transverse ridges. Male. — Unknown. Host and Immature Stages. — The host was origi- nally reported as Pheidole nitudula Emery (Gemignani, 1933). E.O. Wilson identified the same specimens as Pheidole radoszkowskii Mayr (Myrmicinae). Immature stages unknown. Material Examined.— ARGENTINA: Buenos Aires: San Fernando, xi. 1957, Daguerre ( 1 female, USNM); Catamarca: Sumalao, 30.i-5.ii.1958, R. Golbach; Chaco: Resistencia. M.V. Viana ( 1 fe- male, NMBA); Misiones: Dept. Concepcion, Santa Maria. 1948, M.J. Viana (3 females, NMBA); no cityordate( 1 female, NMBA); [province?] Amaicha del Valle, 28.xii.1965, H. & M. Townes ( 1 female, NMBA). PARAGUAY: Caaguazu: Estancia Primera, l.xii.1931 R.F. Hussey (1 female, homotype of O. worcesteri, MMZ). Orasema xanthopus (Cameron) (Figs. 5.6-18) Semora xanthopus Cameron, 1909: 433. Type lo- cality: Argentina, Mendoza. Lectotype, female [examined, BMNH, type number 5.369], here designated. Labels: "Type" "P. Cameron Coll. B.M. 1914-1 10." "Semora xanthopus Cam Type Mendoza" "B.M. TYPE HYM 5.369." Semorata xanthopus: replacement name by Strand 1942, Semora preoccupied by Peckham, 1892. Semorella xanthopus: unjustified replacement name by Ghesquiere, 1946: 368. Orasema xanthopus: combination by Kerrich, 1963: 36. Eucharomorpha paraguayensis Girault, 1913: 63. Type locality: Argentina, Mendoza. Holotype, male [examined, ZHMB], monotypic. Labelsf'Argentina 4.2., Mendoza 07, Jansen Haarup V" "Eucharomorpha paraguayensis Girault male" "S.M.I. Pv. 1045" "ex coll./ Girault" "Zool. Mus./ Berlin." A slide of an antenna of the holotype, as mentioned in the original description, was not examined. The type locality, Mendoza, was taken from holo- type label data; the published locality of San Bernardino (Paraguay) is an error. New syn- onymy. Orasema crassa De Santis, 1968: 3, fig. 1. Type locality: Uruguay, Canelones. Holotype, female [examined, FCNM, type number Za-20 1 ], origi- nally designated. New synonymy. Diagnosis. — Within \.\\q xanthopus-gmuy, both sexes recognized by: frons and mesosomal dorsum finely reticulate; scutellum rounded dorsally (in lateral view) (Fig. 8), axillular sulcus strongly im- pressed and foveate, at least in basal half; mesepimeron and callus mostly smooth, callus with only few minute setae or bare; petiole smooth with weak and irregular longitudinal rugae; femora of female weakly to strongly fuscate medially (Fig. 9), that of male weakly fuscate or completely yel- lowish brown Description of female. — Length, 2.9-3.5 mm. Colour of head and body usually dark (rarely bright) olive or bluish green, sometimes with reddish or stronger bluish reflections. Head 1.3-1.5X as broad as high (Fig. 5). Face strongly reticulate, intertorular area smooth. Eyes separated by 1.7-1.9X their height. Malar space 0.8-0.9X height of eye. Clypeus and supraclypeal area coriaceous and slightly swollen medially. Fla- gellum 1.3-1.6X height of head; FL2 1.7-2.2X as long as broad (Fig. 6). Mesosoma with dorsum finely reticulate, some- times with overlay of irregular alveolate sculpture on midlobe and/or scutellum. Disc of scutellum slightly longer than broad, rounded dorsally (in lateral view) (Fig. 8), and without median furrow; frenum reticulate; frenal line deeply impressed Volume 2, Number 1, 1993 175 ^CXjDCCO Figs. 6-10. Orasemaxcmthopus. 6, antenna of female. 7, antenna of male. 8. head and mesosoma of female. 9. hind femur of female. 10, fore wing of female. Scale bars represent 0.2 mm. 176 Journal of Hymenoptera Research dorsally, reticulate dorsally and glabrous laterally; axillula vertical and weakly reticulate, striate or smooth; axillular sulcus strongly impressed and foveate, sometimes weakly impressed posteriorly. Propodeal disc reticulate laterally, with or without median longitudinal depression; callus swollen and weakly reticulate, at most with 2-3 minute setae dorsally, callar nib present or absent. Upper mesepimeron swollen and weakly reticulate, lower mesepimeron smooth to areolate. Fore wing 2.2- 2.4X as long as broad (Fig. 10). Petiole 1.5-2.4X as long as broad, 0.7-1. OX as long as hind coxa; petiole smooth with irregular longitudinal rugae, the basal flange prominent or weak. First valvula of ovipositor with lateral line of 7 to 8 prominent teeth; second valvula broad with 9 lateral teeth connected dorsally by weak transverse ridges. Description of male. — Length, 2.6-3. 1 mm. Eyes separated by 1.7-1.9X their height. Malar space 0.7-0.9X height of eye. Flagellum (Fig. 7) slightly longer than in female, 2.0-2.2X height of head. Fore wing 2.0-2.4X as long as broad. Petiole 3. 1 -3.4X as long as broad, 1 .2- 1 .5X as long as hind coxa. Distribution (see Fig. 7, Heraty in press-b). — Argentina, Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Uruguay. Variation. — Minordifferences occur in the shape of the body. Specimens from northern Brazil and Ecuador have a generally less robust mesosoma, and the axillula is more distinctly flattened than from southern South America. Fore wings vary in length of the marginal fringe, pilosity of the cubital vein and number of setae surrounding the base of the speculum. Over the range of this species, the anellus may be yellow or brown, but the scape is always a distinct yellow or orangish yellow. The degree of infuscation of the femora of females can vary from only a faint infuscation to an almost complete darkening. Males may have either yellow or infuscate femora, which is typical of other spe- cies of Orasema in which females have dark femora. The holotype male of O. paraguayensis belongs to a dark colored population found in the western Argentinian states of Jujuy, La Rioja and Salta. Individuals of this dark form have the head and mesosoma almost black, and the hind femora of both males and females are dark brown with red- dish reflections. The variation over the vast range of this species may result from differences in either habitat or host. Remarks. — Specimens that were referred to as "Orasema sp." in papers by Wojcik (1988, 1989, 1 990), Wojcik et al. ( 1 987 ) and Vander Meer et al. ( 1 989 ) were examined and belong to this species. A single specimen from the Mato Grosso Province in Brazil (Docias [?], iv.1972, ex Solenopsis nest, USNM) also belongs to this species, and I assume this is part of the material refered to in Williams and Whitcomb (1973) and Williams (1980). Silveira- Guido et al. (1964) refers to "adults" that were reared from S. richteri and identified as O. doellojuradoi by Burks (USNM). Silveira-Guido et al. ( 1 964) state that these were subsequently used by De Santis for his description of O. crassa. De Santis ( 1968) makes no reference to the host of this species, nor to Burks' identification, and only the holotype is known from the type locality. Siviera- Guido et al. (1964) refer to other localities in Uruguay (Colonia San Gregorio and Arrocera San Pedro), but I have not been able to examine these specimens. Habitus drawings in Silveira-Guido et al. ( 1964) appear to be O. xanthopus (although with an elongate petiole as in O. pireta). Host Ant. — Solenopsis invicta and Solenopsis sp. saevissima-comp\ex (Myrmicinae) (De Santis 1968; Williams and Whitcomb 1973; Wojcik 1988, 1989, 1990; Wojcik etal. 1987; Vander Meer etal. 1987), and possibly S. richteri (Silveira-Guido et al. 1964). The range of O. xanthopus is similar to that of the Solenopsis saevissima-comp\ex in South America, as illustrated in Wilson (1952). Trager (1991) distinguished 1 1 species of the Solenopsis saevissima-complex. that occupy various regions of this same range. The distribution of O. xanthopus suggests that it may parasitize more than just the two presently known species. Host Plant. — Unknown. Males have been col- lected resting on grasses and a variety of broad-leaf plants over fire ant nests [a variety of grasses, annuals, herbs, legumes, shrubs, and trees were examined for evidence of egg laying and planidia without success]. Habitat. — Disturbed Cerrado, pantanal, and Campo Limpo. Most of the fire ant colonies col- lected in the 1 984-86 survey were found along road Volume 2, Number 1, 1993 177 shoulders where fire ants flourish. The soils along the roads varied considerably. Fire ant colonies were generally collected in disturbed habitats. Immature stages. Eggs (dissected from abdomen). — Stalked eggs as typical of other Orasema. First-instar larva (Figs. 11-13, 15, 16). — Larval form typical for Orasema and recognized by the following features: three pairs of cranial sensillae, cranial spines absent; terga IV-VI acuminate later- ally, terga VII-VIII strongly scalloped ventrally; caudal cerci short; desclerotized lines from base of setae prominent. Average length of unfed larva 0.21 mm (SD= 0.02, n = 5), maximum size of distended first instar (Fig. 16) 1.20 mm (n=l ). Second-instar larva (Fig. 14). — Recognized by the following characters: body white and unsclerotized; mandibles lacking; only a single mesothoracic spiracle anteroventral of first tubercle; only nine dorsal tubercles present, tubercles slightly raised. Length 1.26 mm (n=l ). Third-instar larva (Fig. 17). — Mature larvae recognized by: body white and poorly sclerotized, dorsal surface smooth; oral region with circular region of fine striae convergent to midline, man- dibles lacking; two thoracic and seven abdominal spiracles present on raised tubercles on body seg- ments II-X; body segments II-X with nine enlarged dorsolateral tubercles, segments I-X with series of ten smaller lateral tubercles; segments II and III with pair of medially divided tubercles lateral to oral region. Average length of pupa 2.81 mm (SD=0.13. n=10). Prepupa recognized by defini- tion of antenna] segments on ventrolateral margins of abdominal segments and by tubercles more promi- nent. Pupa (Fig. 8). — Pupal form is typical for other species of Orasema and is recognized by: three enlarged tubercles over petiole; five transverse abdominal ridges with prominent tubercles dor- sally (much larger than for other species), laterally and subventrally. Average length 3.43 mm (SD=0.21,n=10). Material Examined. — [in following list. ?=adult with sex undetermined; L=larvae; P=pupae; PH=phthisergate] ARGENTINA: Jujuy: Palpala, i (1?, NMBA); La Rioja: February (1 female, NMBA); Salta: (1 male, NMBA); Cachi, i (1 fe- male, MLTA); Santiago del Estero: i (1 female, MCZ). BOLIVIA: Santa Cruz: San Matias, iii, ex floated 5. invicta [colony] 86-131 (6P); 5 km E of San Matias, iii, ex floated S. invicta 86- 1 36 ( 1 L, 9P) & 86-137 (3?, 1L, 9P); Las Juntas, xii (2 females, CARN). BRAZIL: Amazonas: Manaus (1 female, USNM); Fonte Boa, ix ( 14 females, CNC); Goias: Jatai, xi (1 female, CNC); Mato Grosso: Caceres, ex 5. invicta 86-49 & 86-102 (5 females, 2 males, 6L. 9P, JMH); Caceres, viii, ex S. invicta 85-450 (15 females, 3 IP, JMH); Caceres, viii, 85-388, ex S. invicta (15 females, 4 males, 6P, JMH, NMBA); Docias[?], iv, Solenopsis nest (1 female, USNM); Fazenda Paiol, BR-070, km 677, 50 km E of Caceres, vii, ex floated S. invicta 85-388 ( 1 3?, 3L, 35P, 7PH, FLA); Fazenda Sta. Isabel, Reserve do IBDF, MT- 060, km 118 (Transpantaneira), xii, ex floated S. invicta 84-306 (4?, 6P, FLA); Fazenda SATO, BR- 070, km 708, 19 km E of Caceres, xi, ex floated 5. invicta 86-570 (7?, 23L, 135P. 1PH, FLA); Fazenda SATO, BR-070, km 708, 1 9 km E of Caceres, xi, ex floated S. invicta 86-571 (2?, 33L, 157P, 1PH skin with large larva attached, JMH ): Porto Jofre, xii, ex floated 5. invicta 84-296 ( 1 ?, FLA); Quatro Marcos, Fazenda Bela Vista, iv, ex floated S. invicta 85-B- 164(3?, 3L.20P, 1PH, FLA); Seteporcos, BR-070, km 616, ( 100 km W of Cuiaba), viii, ex floated S. invicta 86-B-451 (2?, 1L,8P. FLA); Jacobina, BR- 070. km 701 , 26 km E of Caceres, viii, ex floated S. invicta 85-421 (5?, 17P, FLA); Jacobina, BR-070, km 701, Jacobina, 26 km E of Caceres, viii, ex floated S. invicta 85-422 (5?, 13P, FLA); Mato Grosso do Sul: Corumba ( 1 female, USNM); MS- 80, 48 km NW of Campo Grande, ii, ex floated S. invicta 86-B-49 (19?, 67L, 412P, 46PH, JMH) & also 2 males flying over same colony; same local- ity, iii, 86-B-64 (23?, 5L, 3 1 2P, 1 3PH, JMH); same locality, iii, 86-B-65 (59?, 53L, 444P, 2 1PH, FLA, NMBA) & 10 flying over same colony; same local- ity, vi, 86-320 (4?, 7L, 19P, 1PH skin, FLA); Rochedo, iii, ex floated 5. invicta 86-B-102 (2P, FLA); Jacobina, BR-70, km 32. viii. 85-422 & 85- 421, ex S. invicta (4 females, 5 males, JMH); Para: Belm, vii (1 male, USNM); Jacareacanga, xii (5 females, AEI); Santarem (1 female, CARN); Santarem (3 females, USNM). COLOMBIA: Amazonas: Leticia, ii, MT (4 females, CNC). EC- UADOR: Napo: Cocoa River, iv (2 females, CNC); 178 Journal of Hymenoptera Research 18 Figs. 1 1-19. 1 1- 1 8. Immature stages of Orasemaxanthopus. 1 1, unfed first-instar, dorsal (left) and ventral (right) view. 12, head of unfed first instar in lateral view. 13, first instar larva: a, external position of first instar (arrow) on second-instar larva of Solenopsis invicta; b, partially fed first instar beneath cuticle of fourth-instar larva of Solenopsis. 14, second instar feeding on host pupa. 15, partially fed first instar removed from host larva. 16, first instar feeding in external position on host pupa. 1 7, mature third instar in lateral view. 1 8, pupa in dorsolateral view. 19, O. salebrosa, metasoma of female pupa. Scale bars represent mm in following scales: II, 12 = 0.04; 13, 16 = 0.5; 15 = 0.05; 14, 17-19 = 1.0. Volume 2, Number 1, 1993 179 Tena, ii (5 females, CNC); Tena, ii (2 females, CNC); Tena, ii (2 females. CNC); Puerto Misahuali, 350m, ii (1 female, CNC); Limoncocha, ii (4 fe- males, CNC); Limoncocha on Rio Napo, i-iii MT ( 8 females, FLA). GUYANA: Georgetown, vi ( 1 fe- male, UMS). PERU: Loreto: Dept. Loreto Explorama Inn, 40 km NE Inquitos on Amazon R., vii (1 female, CNC); Madre de Dios: Avispas, 400m, ix. (4 females, CNC). URUGUAY: Artigas, iii, fire ant project (2 females, USNM). Behaviour of O. xanthopus. — Observations on O. xanthopus parasitizing S. invicta were made as part of a survey to evaluate the natural biological control agents of fire ants in Mato Grosso ( MT) and Mato Grosso do Sul (MS), Brazil. The survey was conducted by flotation examination of standard- ized fire ant nest samples of 2-1/2 liters of tumulus (Wojcik 1988). From June 1984 through December 1986, 1585 fire ant colonies were sampled. Most colonies were collected within 150 km of Caceres (MT); some samples were collected near Cuiaba and along the Transpantaneira highway from Pocone to Porto Jofre (MT), 228 colonies from within 200 km of Campo Grande (MS), and 16 colonies from western Bolivia. Orasema xanthopus occurred in 33.2% of the collections from Solenopsis nests made in the Cen- tral-West region of Brazil, and was the most com- monly collected myrmecophile in S. invicta (=saevissima-comp\ex) nests (Wojcik 1988). The average number of parasites collected was 18.3 per nest, although one colony contained 598 O. xanthopus larvae, pupae, and adults. Larval counts do not include first-instar larvae and parasitism rates are higher than was first recorded. Monthly collection data show a consistent presence of all life stages with O. xanthopus present in 18.5-67.5% of colonies examined throughout the year (Table 1 ). Aspects of biology for this species, studied in laboratory fire ant nests, are similar to other Orasema species (Wheeler 1907, Johnson et al. 1986). The particular plants utilized by this species for ovipo- sition were not determined. First-instar larvae were found on the external surface of second-instar ant larvae or just under the cuticle of mature ant larvae (Figs. 8, 9), entering the host at various locations on the dorsal region of the thorax and abdomen. Only one endoparasitic first-instar larva was observed per host larva or pupa. Partial endoparasitic feed- ing, as evidenced by distention of the first-instar larva (Fig. 1 1), took place only after the parasite burrowed into the host ( Fig. 9 ). After host pupation, the now ectoparasitic first and later instars feed on the ventral region of the thorax, between the de- formed pupal legs of the host (Fig. 12). Mature larvae detach themselves from the host after feed- ing is completed. The host may or may not be entirely consumed, we have 3 examples of large O. xanthopus larvae with their heads ( mouthparts (still inserted in the cuticular skins of completely or mostly consumed ant pupae. Deformed host pupae, resulting from incomplete feeding, remain alive within the nest and are here referred to only as phthisergates (after Wheeler 1907). Phthisergates may live for some time in the colonies, but never develop into adult ants. Their presence is diagnostic of parasitism by Orasema. During the pupal period, parasite pupae are mixed in with host brood, and are cared for like ant pupae (Silveira Guido et al. 1964, Williams 1980, Wojcik 1990). Worker ants assist eclosion by the parasite pupae in the same manner as the ants assist their own pupae ( Silveira Guido et al. 1 964, Wojcik 1990). Fed and groomed by the worker ants, adult parasites are temporarily integrated into the colony (Silveira Guido etal. 1964, Williams 1980, Wojcik 1 990). When a nest is disturbed, the pupal and adult parasites are rescued by the ants seemingly in preference to their own brood (Wojcik 1990). Sev- eral ants in the alcohol samples were found clutch- ing the dorsal nodes of larvae and pupae. The manner in which adults of O. xanthopus leave the nest has not been observed. Males hover over the ant nest, or rest on grasses and other plants around and over the fire ant nests (Williams 1980, Wojcik & Jouvenaz unpublished ). Mating swarms, with males flying in a low swarm over the fire ant mound, were observed over a three-day period at one site in Mato Grosso do Sul (MS-80) in March, 1986. Case 1: colony 86-B-49, 4 days after being disturbed by digging; flight activity was high when observations started at 8:45 AM, with activity sub- siding by 9: 15 A.M., but continuing until 9:34 A.M. with an increase in winds and temperature, none of the other 15 other mounds within 100 m showed any flight activity of Orasema. Case 2: colonies 86- 180 Journal of Hymenoptera Research o c o -a s 3 o U NO 00 ON cu -O s CD U u Q "t oo ON 2 CO 0 ~ U £ CD CO 4-H > * CO * g 5 GO 0) En B <3 _2 6 0 U 1? GO O ■a u 3 3 g I 3 U CO X (LI -3 q c 2 en 00 SO o Z NO ON NO a Volume 2, Number 1, 1993 181 B-64 & 86-B-65, 3 days after being disturbed by digging, 86-B- 65 moved 1 m NW; flight activity was observed at 1 1 AM after sun appeared from clouds (heavy overcast until then); winds calm. Case 3: colonies 86-B-64 & 86-B-65, 4 days after being disturbed by digging; flight activity was high when observations started at 9:1 1 AM, light over- cast till 10:25 then full sun, sporadic flying with full sun for 1/2 hr before wasps ceased to fly, one of the other 6 mounds within 100 m had flight activity; winds calm. Wojcik observed several males that approached and attempted to mount other resting males on grass leaves or stems over the ant mound at the edges of the swarm. The standing males repelled the apparently misguided males by wing flipping, by antennal fencing, or by leaving the area. Mating takes place immediately after adult para- sites leave the nest (Williams 1980). Based on the relatively even distribution of the larvae, pupae, and adults collected (Table 1 ). it seems likely that overlapping multiple generations occur in Central- West Brazil and mating takes place whenever weather conditions are suitable. No fire ant mating flights occurred during the wasp mating swarms (from any colonies within walking distance) and no unusual fire ant activity was observed on any of the studied mounds. Studies of cuticular hydrocarbons have shown that O. xanthopus larvae, pupae and adults possess only host Solenopsis sp. cuticular hydrocarbons while in the ant nest. After leaving the host nest, adult O. xanthopus acquire species-specific cuticu- lar hydrocarbons and lose the majority of the host Solenopsis sp. cuticular hydrocarbons ( Vander Meer etal. 1989). ACKNOWLEDGEMENTS We thank J. Huberand M. Sharkey (CNC) for their reviews of this manuscript. This work was supported by a National Sciences and Engineering Research Council of Canada postdoctoral fellowship to JMH. Studies conducted in Brazil (DPW, DPJ and J. Senatore) were part of a cooperative agreement between the USDA- ARS and EMBRAPA (Empresa Brasileira de Pesquisa Agropecuaria). Material was borrowed or examined with the help of the following curators: D. Wahl, Ameri- can Entomological Institute, Gainesville, FLA ( AEI ); Z. BouCek and J. Noyes, The Natural History Museum, England (BMNH); G. Gibson, Canadian National Insect Collection. Canada (CNC); Carnegie Museum of Natu- ral History, Philadelphia, PN (CARN); L. DeSantis and R. Ronderos. Facultad de Ciencias Naturales y Museo, La Plata, Argentina (FCNM); J. Wiley, Florida State Collection of Arthropods, Gainesville, FL (FLA); J. Heraty (JMH); Museum of Comparative Zoology, MA (MCZ); T. Moore, Michigan University, Ann Arbor, MI (MMZ); A. Bachmann. Museo Argentina de Cincias Naturales "Bernardino Rivadavia." Buenos Aires, Ar- gentina (NMBA); P. Fidalgo. Miguel Lillo Institute Tucuman, Argentina (MTLA); P. Clausen, University of Minnesota, St. Paul MN (UMS); E. Grissell, United States National Museum of Natural History, DC (USNM); F. Koch, Zoologisches Museum, Humbolt-Universitat, East Berlin, Germany (ZHMB). LITERATURE CITED BouCek, Z. 1988. Australasian Chalcidoidea (Hy- menoptera). Wallingford: C. A. B. International. 832 pp. Cameron, P. 1909. A contribution to the knowledge of the parasitic Hymenoptera of Argentina. Transac- tions of the American Entomological Society 35: 419-450. De Santis, L. 1968. Una nueva especies de "Orasema" del Uruguay (Hymenoptera: Eucharitidae). Revista de la Sociedad Entomologica de Argentina 31: 1-3. Gemignani. E. V. 1933. La familia "Eucharidae" (Hy- menoptera: Chalcidoidea) en la republica Argentina. Anales del Museo Nacional de Historia natural de Buenos Aires 37: 477-493. Ghesquiere, J. 1946. Contributions a l'etude des Microhymenopteres du Congo beige X-XI. Revue de Zoologie et de Botanique Africain 39: 367-373. Girault, A. A. 1913. More new genera and species of chalcidoid Hymenoptera from Paraguay. Archives fur Naturgeschichte 79, Abt. A, Hft. 6: 5 1 -69. Heraty, J. M. 1989. Morphology of the mesosoma of Kapala (Hymenoptera: Eucharitidae), with empha- sis on its phylogenetic implications. Canadian Jour- nal of Zoology bl : 115-125. Heraty, J. M. in press-a. Classification and evolution of the Oraseminae in the Old World, including revi- sions of two closely related genera of Eucharitinae (Hymenoptera: Eucharitidae). Life Sciences Contri- butions of the Royal Ontario Museum (369 pp). Heraty, J. M. in press-b. Biology and importance of two eucharitid parasites of Wasmannia and Solenopsis. 182 Journal of Hymenoptera Research In D. Williams (ed), Exotic Ants, Their Impact and Control. Westview Press. Johnson, J. B., T .D. Miller, J. M. Heraty and F. W. Merickel. 1986. Observations on the biology of two species of Orasema (Hymenoptera: Eucharitidae). Proceedings of the Entomological Society of Wash- ington 88: 542-549. Kerrich, G. J. 1963. Descriptions of two species of Eucharitidae damaging tea. with comparative notes on other species (Hymenoptera: Chalcidoidea). Bul- letin of Entomological Research 54: 365-37 1 . Silveira-Guido, A., P. San-Martin. C. Crisci-Pisano and J.Carbonell-Bruhn. 1964. Investigations on the biol- ogy and biological control of the fire ant, Solenopsis saevissima richteriForel in Uruguay. Third Annual Report. Deptartmento de Sanidad Vegetal, Facultad de Agronomia, Universidad de la Repiiblica, Montevideo, Uruguay, 67 pp. Strand, E. 1 942. Miscellanea nomenclatoria zoologica et palaeontologica X-XII. Folia Zoologica et Hydrobiologica 11: 386-402. Trager, J. C. 1991. A revision of the fire ants, Solenopsis geminata group (Hymenoptera: Formicidae: Myrmicinae). Journal of the New York Entomologi- cal Society 99: 141-198. Wheeler, W.M.I 907. The polymorphism of ants with an account of some singular abnormalities due to parasitism. Bulletin of the American Museum of Natu- ral History 23: 1-100. Williams, R. N. 1980. Insect natural enemies of fire ants in South America with several new records. Pro- ceedings of the Tall Timbers Conference on Ecology, Animal Control and Habitat Management 7: 123- 134. Williams, R. N. and W. H. Whitcomb. 1973. Parasites of fire ants in South America. Proceedings of the Tall Timbers Conference on Ecology, Animal Control and Habitat Management 5: 49-59. Wilson, E. O. 1952. O complexo Solenopsis saevissima na America do Sul (Hymenoptera: Formicidae). Memdrias do Instituto Oswaldo Cruz 50:49-59. (En- glish version, ibid. pp. 60-68). Vander Meer, R. K., D. P. Jouvenaz, and D. P. Wojcik. 1989. Chemical mimicry in a parasitoid (Hy- menoptera: Eucharitidae) of fire ants (Hymenoptera: Formicidae). Journal of Chemical Ecology 15: 2247- 61. Wojcik. D. P. 1988. Survey for biocontrol agents in Brazil - a final report, with comments on preliminary research in Argentina. Proceedings of the 1988 Imported Fire Ant Conference pp. 50-62. Wojcik. D. P. 1989. Behavioural interactions between ants and their parasites. Florida Entomologist 72: 43- 51. Wojcik, D. P. 1990. Behavioral interactions of fire ants and their parasites, predators and inquilines. pp. 329- 44. In R.K. Vander Meer, K. Jaffe, A. Cedeno (ed.). Applied myrmecology, a world perspective. Westview Press, Boulder, CO, 741 pp. Wojcik, D. P., D. P. Jouvenaz, W. A. Banks, and A. C. Pereira, 1987. Biological control agents of fire ants in Brazil, pp. 627-628. In J. Eder, H. Rembold (ed.). Chemistry and biology of social insects. Verlag J. Peperny, Miinchen. 757 pp. J. HYM. RES. 2(1), 1993 pp. 183- 188 Nesting Biology of Microstigmus myersi Turner, a Wasp With Long-haired Larvae (Hymenoptera: Sphecidae, Pemphredoninae) Gabriel Augusto R. de Melo1 and Lucio Antonio de O. Campos Departamento de Biologia Geral. Universidade Federal de Vieosa. 36570 Vieosa MG. Brazil; '(GARM) Present address: Department of Entomology. University of Kansas, Lawrence. Kansas 66045 Abstract. — This paper describes the nesting habits of Microstigmus myersi, a species which builds nests with dirt particles hanging on fine roots in banks. The nest has no petiole and rests directly on the end of a rootlet. The entrance is shaped like a tube and is located in the lower part, whereas the cells are located above, forming the upper part of the nest. This species performs semiprogressive provisioning and preys on Thysanoptera nymphs. Microstigmus myersi larvae have long hairs on their body. Considering the orientation of the brood cells of this species, the larval hairs seem to represent an adaptation that may permit better support within the cells. The larvae have spinnerets and spin a cocoon, in contrast to what occurs in most other Microstigmus species. The nests of M. myersi are parasitized by Heterospilus sp. (Braconidae), and also by Ceraphron sp. (Hymenoptera, Ceraphronidae). The large number of cells in some of the nests seems to indicate long duration of these nests and. indirectly, the possibility of reuse by descendants. The nests normally contain more than one female and some males. The genus Microstigmus Ducke is a highly in- teresting group within the Sphecidae, especially because of its nests and the social behavior exhib- ited by some of its species (Matthews 1968a, 1968b, 1991; Richards 1972; West-Eberhard 1977; Ross and Matthews 1 989a). In general the nests are small sacs built with particulate material aggregated with silk produced by females (Matthews 1968b; West- Eberhard 1977; Matthews and Starr 1984). In most species these sacs hang on a fine petiole (West- Eberhard 1977). Although Microstigmus is widely distributed in the Neotropical region, little is known about its biology. Only M. comes Krombein, a species found in Costa Rica, has been studied in some depth. This species nests under the leaves of palms of the genus Cryosophyla Blume and builds spherical nests us- ing material scraped off the bottom surface of the leaves (Matthews 1968b; Matthews and Starr 1984). Ross and Matthews (1989a, 1989b) have presented evidence that most of the colonies may be eusocial, with task division among females based on size. Some aspects of the nesting biology of M. myersi Turner were first reported by Myers ( 1 934). Myers did not provide a very detailed report on the biology of M. myersi but stated that the nest is quite similar to that of M. theridii Ducke in general appearance. size and structure. The nest found by him was suspended by a long fine rootlet, under a bank, and had numerous earth pellets incorporated in the walls. The present paper reports on aspects of the nesting habits of M. myersi. The descriptions are based on ten nests collected on the campus of the Federal University of Vieosa (MG), Brazil, from April 1989 to January 1992. Nest structure and cell contents were examined under a stereoscopic mi- croscope. Observations made directly at the nesting sites on other nests that were not collected are also reported. The species was identified by the first author. Vouchers specimens are deposited in the Entomological Museum of the Federal University of Vieosa and in the Museu de Zoologia da Universidade de Sao Paulo (MZSP). NESTING SITE AND NEST ARCHITECTURE Nests of M. myersi were found only on steep banks mainly along roads and paths inside or close to wooded areas. As described by Myers ( 1934), the nests hang from fine rootlets. In general they are inconspicuous because of their similarity to the numerous dirt clumps also hanging from fine roots (Fig. 1 ). The schematic drawing presented in Fig. 1 is typical of the banks used by M. myersi (presence 184 Journal of Hymenoptera Research of an upturned edge in the upper part containing many root ends). Normally the nests are not clus- tered, although as many as four nests were found close to one another in the same bank. The nest architecture is quite different from that found in other Microstigmus species whose nest architecture is known. The nest has no petiole and rests directly on the end of a rootlet. The entrance is shaped like a tube and is located in the lower part, whereas the cells are located above, forming the upper part of the nest (Fig. 2). In new nests, all cells are vertically oriented with their opening looking down (Fig. 3b). As the nest grows, additional cells are oriented obliquely (Fig. 3a). Fig. 1. Cross-section of a typical bank used as nesting site by Microstigmus myersi. Only one nest is represented in the sketch. Volume 2, Number 1, 1993 185 Fig. 2. Nest of Microstigmus myersi. Note the silk around the suporting rootlet on the upper part of the nest. Scale line = 5mm. The walls of the nest are built with dirt particles aggregated with silk produced by females. Inter- nally, the nest is fully lined with silk. The region of transition between the supporting root and the nest wall on the upper part is covered with a lot of silk, which gives it a whitish color. In general, the nests are built at the end of the rootlets, so that the rootlet tip is always inside the nest. However, in some nests the root extends beyond the nest (Fig. 3b). In most of the nests found, the outlines of the cells can be discerned on the outer surface of the nest (Fig. 2), although one nest had a spherical outer contour (Fig. 3a). This latter nest was covered with a weak layer of dirt particles and, judging from the number of cells (23), appeared to be quite old. Observations revealed that these particles are gradu- ally brought by females and attached to the outer part of the nest with silk. The females climb up the supporting root to the region where the root pen- etrates the bank and bring back dirt particles hold- ing them between their mandibles. It seems that all nests tend to develop a smoother outer surface as they get older. West-Eberhard ( 1977, Fig. 2B) has presented a schematic drawing of a nest with architecture simi- lar to that of M. myersi. The author refers to this nest as belonging to a new well-distinct species. It is possible that this species belongs to the same group as M. myersi. The differences between the nests of M. myersi found at Vicosa and that described by Myers may Fig. 3. Cross-section of Microstigmus myersi nests: a - old nest; b - newly founded nest. 186 Journal of Hymenoptera Research be due to an error he made in describing the orien- tation of the nest. On the other hand, the material found in Vicosa may belong to another species closely related to M. myersi. NEST CONTENTS AND IMMATURES Table 1 summarizes the contents of the nests. The cells of M. myersi are provisioned with Thysanoptera nymphs and not with Collembola, as suggested by the title of the study by Myers (1934). Microstigmus myersi performs semi-progressive provisioning since cells with eggs contained only 3 to 15 Thysanoptera nymphs. Furthermore, the nymphs are placed loose within the cell and do not form a compact mass as observed in species per- forming mass provisioning. The number of prey in cells with immature larvae was similarto that found in cells with eggs, excepting some immature larvae that were found in cells that did not contain food provisions. As in other Microstigmus species, the preys are supported in the cells by silk threads. Contrary to what is observed for most Apocrita, M. myersi larvae have long hairs on their body. In 1st- and 2nd-instar larvae, the hairs are short (Fig. 4b), whereas in older larvae they are longer and curved at the end (Fig. 4a). Among Sphecidae. hairy larvae are encountered only in a few genera not related to Microstigmus (Evans 1959). Considering the orientation of the brood cells of this species, the hairs of M. myersi larvae seem to represent an adaptation that may permit better sup- port within the cells. These hairs may attach to the silk threads placed by female on the cell bottom to support eggs and prey, thus permitting the larva to stay suspended within the cell. There are evidences that the nest architecture of M. myersi evolved independently from that found in the species with pendulous nests and with glabrous larvae (Melo, in prep.). Lanham ( 1979) stated that the larval hairs found in ants and allodapine bees probably represent an adaptation for life in a communal brood chamber. Lanham (1980), in a discussion on the origin of Table l.i Contents of Microstigmus myersi nests collected in Vicosa (MG), B razil [. ADULTS NUMBER EMPTY NUMBER OF CELLS WITH NEST PREYS a EGG LARVA PREPUPA PUPA PARASITES NUMBER F M OF CELLS CELLS ONLY F M — - - 23 14 0 03 02 02 2 0 0 — 1 0 03 01 0 02 0 0 0 0 0 A 5 3 12 01 01 01 01 04 4 0 0 B 1 2 07 02 0 02 02 0 1 0 0 296 2 1 08 0 01 0 02 03 1 1 0 328 2 0 18 05 01 01 03 03 3 1 01 376 3 1 09 01 03 01 01 0 2 0 01 584 2 1 08 0 01 01 01 0 2 2 03 586 4 2 13 05 01 02 0 0 2 0 589 1 0 07 0 01 02 02 02 0 0 0 a. Although Microstigmus myersi exhibits semi-progressive provisioning, the number of cells that possess only thrips nymphs is also indicated. b. Heterospilus. c. Ceraphron. Volume 2, Number 1, 1993 187 Fig. 4. Larvae of Microstigmus myersi: a - predefecating larva; b - young larva. Scale line = I mm. B bees, hypothesizes that in the yet unstudied species of Microstigmus there may be found an evolution- ary sequence in which cell making is abandoned and the larvae have become hairy. As previously mentioned, although M. myersi has hairy larvae, the immatures of this species are reared in individual cells. In all Microstigmus species whose nest archi- tecture is known, the immatures are reared in indi- vidual cells. Microstigmus myersi larvae have spinnerets and spin a cocoon, in contrast to what occurs in most other Microstigmus species (Melo, in prep. ). After cocoon spinning, the larvae orient with their head facing outward and their anal end facing the vesti- bule. All prepupae and pupae were found within a cocoon and facing outward. The adults make holes in the cocoon in the region of cell opening and remove the larval feces. The feces stick to the inner wall of the cocoon and are not always fully removed by the adults. This cleaning behavior by the adults was inferred from the observation of the cap of cells containing predefecating larvae, prepupae and pu- pae. The cells are probably cleaned completely only after imago emergence. PARASITOIDS The nests of M. myersi are parasitized by a species of Heterospilus Haliday differing from H. microstigmi Richards (Braconidae). Heterospilus microstigmi is testaceous in color and its larvae spin a thin cocoon, while this other species has a black body and its larvae spin a very rigid cocoon. The imagoes of this Heterospilus species emerge from the cell through a hole in the cocoon which they make at the end facing the outer side of the nest. It is common to find cells which have been opened outward and are closed inside and which are lined with a rigid cocoon, indicating an emer- gence by the parasitoid. Microstigmus myersi adults apparently are un- able to open these cocoons, so that parasitized cells become useless. In some older nests, the entire upper part of the nest can be formed by this type of cell. In general, the opening made in the cocoon by the parasitoid is closed by the wasps with silk and dirt particles. In one nest (N376), we also found a cell parasit- ized by a species of Ceraphron Jurine (Ceraphronidae), in which five larvae were eating a prepupa. SOCIAL ORGANIZATION Little can be inferred about the social organiza- tion of M. myersi from the present data. The large number of cells in some of the nests seems to indicate long duration of these nests and, indi- rectly, the possibility of reuse by descendants. Cell reuse was also inferred by the presence of eggs or 188 Journal of Hymenoptera Research immature larvae in cells lined with cocoons. The nests normally present more than one female and some males (Table 1). The relationship between number of cells with eggs and larvae and number of females does not permit us to draw conclusions about the occurrence of dominance among females. Although no quantitative analysis was performed, nest-sharing females do not exhibit marked differ- ences in size. Adults walking over the nest are commonly observed, a behavior which appears to be related to defense against parasitoids, as also observed by Matthews ( 1968b) in M. comes. Since the males of M. myersi are not easily distinguished from females in field conditions, we do not know if the males also exhibit this behavior. ACKNOWLEDGMENTS We thank B. Alexander, M. A. Costa and F. A. Silveira for their valuable comments on the manu- script and also to P. Fidalgo for the identification of the Ceraphronidae. LITERATURE CITED Evans, H. E. 1 959. Studies on the larvae of digger wasps (Hymenoptera, Sphecidae). Part V: Conclusion. Transactions of the American Entomological Society 85: 137-191. Lanham, U. N. 1979. Possible phylogenetic significance of complex hairs in bees and ants. Journal of the New York Entomological Society 87: 91-94. Lanham, U. N. 1980. Evolutionary origin of bees (Hy- menoptera: Apoidea). Journal of the New York Ento- mological Society 88:199-209. Matthews, R. W. 1968a. Microstigmus comes: sociality in a sphecid wasp. Science 160: 787-788. Matthews, R. W. 1968b. Nesting biology of the social wasp Microstigmus comes. Psyche 75: 23-45. Matthews, R. W. 1991. Evolution of social behavior in sphecid wasps, pp. 570-602. In Ross, K. G. and Matthews, R. W. eds. The Social Biology of Wasps. Comstock, Ithaca. Matthews, R. W. and C. K. Starr. 1984. Microstigmus comes wasps have a method of nest construction unique among social insects. Biotropica 16: 55-58. Myers, J. G. 1934.TwoCollembola-collectingcrabronids in Trinidad. Transactions of the Royal Entomologi- cal Society of London 82:23-26. Richards, O. W. 1972. The species of the South Ameri- can wasps of the genus Microstigmus Ducke (Hymenoptera:Sphecoidea, Pemphredoninae). Trans- actions of the Royal Entomological Society of Lon- don 124: 123-148. Ross, K. G. and R. W. Matthews. 1989a. New evidence for eusociality in the sphecid wasp Microstigmus comes. Animal Behaviour 38:613-619 Ross, K. G. and R. W. Matthews. 1989b. Population genetic structure and social evolution in the sphecid wasp Microstigmus comes. The American Naturalist 134:574-598. West-Eberhard, M. J. 1977. Morphology and behavior in the taxonomy of Microstigmus wasps, pp. 123- 125. Proceedings of the 8th International Congress of the 1USSI. The Netherlands. J. HYM. RES. 2(1), 1993 pp. 189- 194 Sawflies of the Genus Perineum Hartig from Japan (Hymenoptera: Tenthredinidae) ICHUI TOGASHI [shikawa Agricultural College. 1-308. Suematsu, Nohoichi-machi Ishikawa Prefecture. 921 Japan Abstract. — Two new species of Perineura from Japan are described and illustrated. P. kamikochiana, sp. nov., and P. nigra, sp. nov. A key and illustrations are provided for separation of the Japanese species of Perineura. Perineura is a small genus in the subfamily Perineura Hartig Tenthredininae. It was represented by six species in Europe and Japan, [n Japan, five species, P. esakii Perineura Hartig, 1837: 303. Type species: Takeuchi. P. pictipennis Takeuchi, P. japonica Tenthredo rubi Panzer, by monotypy. Malaise, P. stigma Takeuchi. and P. okutanii Synairema Hartig, 1837: 314. Type species: Takeuchi. were recorded. Recently, I had an oppor- Tenthredo delicatula Klug (= Perineura rubi tunity to examine 27 specimens of Perineura col- Panzer), by monotypy. lected in Japan. They represent seven species. including two new species, P. nigra and P. Diagnosis.— Clypeus with anterior margin kamikochiana, which are described below. Al- deeply and subtriangularlyemarginate; malar space though Benson (1952) stated that the male of the broad, nearly 2X diameter of front ocellus; occipi- European species, Perineura rubi (Panzer), is far tal carina well defined on entire occipital margin; more commonly found than the female, most of the antenna fairly long, 2X or more head width and specimens I have from Japan are females, and the filiform, 3rd and 4th segments nearly equal in males are not known or have not been associated length; anal cell of forewing with 2A+3A meeting with females. Also, the Japanese species described 1 A or with a short straight anal crossvein at about by Takeuchi (1959) and Malaise (193 Dare based basal third; hindwing with two middle cells in on females. Consequently, this review is based on female and a marginal vein in male; first abdominal females. Host plants of the species in Japan are tergum divided; tarsal claw with short inner tooth, unknown. much smaller than outer tooth. KEY TO FEMALES OF THE JAPANESE SPECIES OF PERINEURA 1. Antenna black (Fig. 9); forewing without a dark band below stigma (Figs. 12, 14-16) or with a small pale fleck below stigma (Fig. 13); japonica group 3 — Antenna with three apical segments white (Fig. 8); forewing with a dark band below stigma (Figs. 10. 1 1 ); esakii group 2 2. Tegula black, scutellum and posttergite nearly white; lancet with 20 serrulae, with basal 3 serrulae as in Fig. 31 esakii Takeuchi — Tegula white, scutellum and posttergite nearly black; lancet with 19 serrulae, with basal 3 serrulae as in Fig. 32 pictipennis Takeuchi 3. Abdomen nearly fulvous (Figs. 26-28) 4 — Abdomen black (Fig. 30), or 2nd to 7th abdominal tergites with yellow fleck (Fig. 29) 6 4. Forewing with a pale brown fleck below stigma (Fig. 13); color pattern of abdomen as in Fig. 27; sawsheath as in Fig. 22; lancet with 19 serrulae, with basal 3 serrulae as in Fig. 34 stigma Takeuchi igg Journal of Hymenoptera Research — Forewing without a pale brown fleck below stigma (Figs. 12, 14-16); other features various 5 5. Stigma of forewing nearly uniformly pale reddish yellow (Fig. 12); mesonotum with some yellow flecks ( Fig. 1 7 ); color pattern of abdomen as in Fig. 26; sawsheath as in Fig. 2 1 ; lancet with 1 9 serrulae, with basal 3 serrulae as in Fig. 33 japonica Malaise — Stigma of forewing dark brown with basal third white (Fig. 14); mesonotum black; color pattern of abdomen as in Fig. 28; sawsheath as in Fig. 23; lancet with 19 serrulae, with basal 3 serrulae as in Fig. 35 okutanii Takeuchi 6. Abdomen black; mesonotum and mesepisternum black; sawsheath as in Fig. 25; lancet with 20 serrulae, basal 3 serrulae as in Fig. 37 nigra, sp. nov. — Abdomen black with yellow fleck on 2nd to 7th tergites ( Fig. 29); mesonotum with a V-like fleck (Fig. 18) and mesepisternum with a yellow fleck; sawsheath as in Fig. 24; lancet with 19 serrulae, with basal 3 serrulae as in Fig. 36 kamikochiana, sp. nov. Abdomen: Normal; sawsheath as in Fig. 24; Perineura kamikochiana Togashi, sp. nov. lancet with 19 serrulae. basal 3 serrulae as in Fig. 36. Female. — Length, 8.0 mm. Body black with Punctation: Head covered with fine setigerous following parts pale yellow to yellow: upper half of punctures but supraclypeal area nearly impunctate, inner and hind orbits (Fig. 6), anterior half of shining; basal half of clypeus sparsely and finely clypeus, labrum, basal half of mandible, maxillary punctured; cheek covered with medium sized punc- and labial palpi, tegula, pronotum, V-like fleck on tures. Pronotum, praescutum, and thorax ventrally mesonotum (Fig. 18), mesoscutellum except for covered with fine setigerous punctures; mesonotal posterior third, posttergite, most of metascutellum, lateral lobes, sunken areas, mesoscutellum except central portion of metanotum, fleck on for posterior 1/4, and posttergite nearly impunctate, mesepisternum, triangular-like fleck on 2nd to 7th shining; posterior 1/4 of mesoscutellum distinctly tergites, 8th and 9th tergites except for black lateral and evenly punctured, but posterior margin rugoso- sides (Fig. 29), cercus, and 7th and 8th abdominal reticulately sculptured. Abdominal tergites sternites. Antenna black. Wings rather yellowish shagreened. hyaline, stigma of forewing pale yellow but apical Distribution. — Japan (Honshu), third dark brown (Fig. 15), costa of forewing dark Holorxpe. — Female, 2 1-23. VI. 1 989, Kamikochi brown, other veins black. Legs yellow, fore and (altitude 1 500 m), Nagano Prefecture, A. Shinohara mid tibiae pale to dark brown, apical portion of hind leg. Deposited in the National Science Museum femur with small dark brown spot. (Natural History), Tokyo. Head: Postocellar area rather flat; postocellar Remarks. — This new species resembles species furrow nearly absent; lateral furrow deep (Fig. 6); assigned to thejaponica group, but is distinguished interocellar furrow distinct but shallow; from them by the mostly black abdomen (species of OOL:POL:OCL = 2. 5: 1.0: 1.0; frontal area slightly the japonica group have the abdomen mostly concave and connected with median fovea; lateral fulvous, see Figs. 26-28). fovea linear; ration between antenno-ocular dis- tance and distance between antennal sockets about Perineura nigra Togashi, sp. nov. 1 .0:0.85; supraclypeal area slightly convex; clypeus nearly flattened; postorbital groove distinct. An- Female. — Length, 8.5 mm. Body black with tenna slightly longer than costa of forewing (ratio following parts pale yellow to yellow: anterior half about 1.0:0.9), relative length of segments about of clypeus, labrum, maxillary and labial palpi, fleck 1 .4: 1 .0:4. 1 :3.5:3.2:2.5:2.2:2.0:2. 1 . on postorbit (Fig. 7), posterior margin of pronotum. Thorax: Normal; wing venation as in Fig. 15; tegula, cenchrus, posterior margin of 1st abdominal hind basitarsus shorter than following 4 segments tergite (Fig. 30), 9th tergite, and cercus. Antenna combined (ration about 1.0:1.3). black. Wings slightly smoky, hyaline, stigma of Volume 2, Number 1, 1993 191 * CO -J -C — U a Si •j F Vh a CJ •a c £3 3 £ 3 — S CJ X! - o U •S3 £ ~ -5 cd o X a X — c -J Ch CD > X1 3 o P '- r m c - tH It <+. Hi > o - CO E T) S3 "o 3 1) 00 CD OS 00 CZ T3 CD O CJ CO T3 CO E Q_ CD CO CD CO T3 3 •;=; CD CO g CO E o co _o CO Q. o sz CD CO ■D "c CD CO .a o C > CO I— CO CD CO ■D 'o O LL CD CO g CO C > o CD +-> CD I CO g "a. CO g 'o CD .C Q. 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HYM. RES. 2(1), 1993 p. 303 SCIENTIFIC NOTE On Odynerus rachiphorus Schletterer, a Masarinae {Trimeria), not a Eumeninae (Hymenoptera, Vespidae) Schletterer ( 1 89 1 ) described five species of Odynerus. all supposedly from Chile. Thanks to the kindness of M. Fischer from the Vienna Mu- seum, we were able to study a male specimen labeled Odynerus rachiphorus in Schletterer' s hand- writing. The specimen was not labeled as a type and it was sent to us as a non-type specimen. A careful comparison of the specimen and Schletterer' s original description shows that he had in front of him a Masarinae (Trimeria) and not a Eumeninae (Odynerus) when he described rachiphorus. The scutellum, the insertion of the antennae close to the eye margins, the lateral pro- cesses of the propodeum punctuate, bearing an apical spine, and the pattern of sculpture of the metasomal terga are descriptive features that prove this and indicate that the Vienna specimen is the holotype. It is interesting to note that it bears a second label "Trimeria rachiphorus" written by Kohl. The species should then bear the name Trimeria rachiphorus (Schletterer) new combina- tion. The holotype corresponds to a species of Trimeria broadly distributed in Argentina and previously known as Trimeria buyssoni Brethes ( 1 904) ( Willink 1951; Richards 1962). Brethes' name is thus a junior synonym of Trimeria rachiphorus (Schletterer), new synonymy. The species has been recorded from the Provinces of Jujuy, Salta. Tucuman, Formosa, Santiago del Estero, Santa Fe, Catamarca and Neuquen in Argentina and also from Paraguay. It has never been found in Chile and we suggest the Schletterer's specimen is mislabeled. The holotype of Odynerus rhodopterus, together with Odynerus fairmairei, are two more species described by Schletterer from Chile that have never been found in that country. LITERATURE CITED Brethes. J. 1 904. Trimeria buyssoni un nuevo masarido argentino. Anales del Museo National de Buenos Aires (3)2:371-374. Richards, O. W. 1962. Arevisional study oj "the masarid wasps (Hymenoptera. Vespoidea). British Museum (Natural History), London. 294 pp. Schletterer, A. 1891. Vespidarum species novae chilensis. Entomologische Nachrichten 17(6):83- 94. Willink. A. 1951. Una nueva especie argentina de Trimeria (Hym.. Masaridae). Revista de la Sociedad entomologica Argentina 15:77-82. A. Willink, Instituto Miguel Lillo, Miguel Lillo 205, 4000 Tucuman, Argentina and A. RoigAlsina. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia",Av. A.Gallardo470, 1405 Buenos Aires, Argentina. INSTRUCTIONS FOR AUTHORS General Policy The Journal ofHymenoptera Research invites papers of high scientific quality reporting comprehensive research on all aspects of Hymenoptera, including biology, behavior, ecology, systematics, taxonomy, genetics and morphology. 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The paper may be submitted in most PC and Mac word processor programs such as Microsoft Word, FullWrite Professional, WordPerfect, WriteNow, Nisus, MacWrite, or MacWrite II; it is important that the manuscript also be formatted as an ASCII or TEXT file. Tables may be formatted in a spread sheet program such as MS Works or MS Excel. Use the words female and male rather than symbols. Text should be double spaced typing, with 25 mm left and right margins. Tables should be put in a separate file. Diskettes should be accompanied by the name of the software program used (e.g., WordPerfect, Microsoft Word). Authors should keep backup copies of all material sent to the Editor. The Society cannot be responsible for diskettes or text mislaid or destroyed in transit or during editing. Illustrations should be planned for reduction to the dimension of the printed page (15.3 X 22 cm, column width 7.5 cm) and allow room for legends at the top and bottom. Do not make plates larger than 14" X 18". Individual figures should be mounted on a suitable drawing board or similar heavy stock. Photographs should be trimmed, grouped together and abutted when mounted. Figure numbers should be on the plate, but it is strongly recommended that names be included after the numbers (e.g., Fig. 2, texanus). Include title, author(s) and address(es), and illustration numbers on back of each plate. Original figures need not be sent until requested by the editor, usually after the manuscript has been accepted. Reference to figures/tables in the text should be in the style "(Fig. 1)" "(Table 1)". Measurements should be in the metric system. All papers must conform to the International Code of Zoological Nomenclature. The first mention of a plant or animal should include the full scientific name including the authority. Genus names should not be abbreviated at the beginning of a sentence. In taxonomic papers type specimens must be clearly designated, type depositories must be clearly indicated, and new taxa must be clearly differentiated from existing taxa by means of keys or differential diagnoses. Basically, the papers must conform to good taxonomic practices. Authors are required to deposit all type material in nationally or internationally recognized institutions (not private collections). Voucher specimens should be designated for specimens used in behavioral or autecologi- cal studies, and they should be deposited similarly. Acceptance of taxonomic papers will not require use of cladistic methods; however, authors using them will be expected to specify the phylogenetic program used (if any), including discussion of program options used. A data matrix should be provided. The number of parsimonious cladograms generated should be stated and the reasons for the one adopted. Lengths and consistancy indices should be provided. References in the text should be (Smith 1999), without a comma, or Smith (1999). Two articles by a single author should be (Smith 1999a, 1999b) or Smith (1999a, 1999b). For papers in press, use "in press," not the expected publication date. The Literature Cited section should include all papers referred to in the paper. Journal names should be spelled out completely and italicized. Charges Publication is free to members of the International Society of Hymenopterists. At least one author of the paper must be a member. Reprints are charged to the author and must be ordered when returning the proofs; there are no free reprints. Author's corrections and changes in proof are also charged to the author. Color plates will be billed at full cost to the author. All manuscripts and correspondence should be sent to: Paul M. Marsh, Editor Systematic Entomology Laboratory U. S Department of Agriculture c/o U.S. National Museum of Natural History NHB 168 Washington, D.C. 20560, U.S.A. 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