This protocol explains how to extract pollen from fossil insects with subsequent descriptions of pollen treatment. We also describe how to document morphological and ultrastructural features with light-microscopy and electron microscopy. It enables a taxonomic assignment of pollen that can be used to interpret flower-insect interactions, foraging and feeding behavior of insects, and the paleoenvironment. The protocol is limited by the state of the fossil, the presence/absence of pollen on fossil specimens, and the availability of extant pollen for comparison. For complete details on the use and execution of this protocol, please refer to Wappler et al. (2015), Ulrich and Grímsson (2020), and Wedmann et al. (2021).

One of the most important trophic interactions today is that between insects and their floral hosts. This biotic association is believed to have been critical to the radiation of flowering plants and many pollinating insect lineages over the last 120 million years (Ma). Trophic interactions among fossil organisms are challenging to study, and most inferences are based on indirect evidence. Fossil records providing direct evidence for pollen feeding, i.e., fossil stomach and gut contents, are exceptionally rare.1,2 Such records have the potential to provide information on aspects of animal behavior and ecology as well as plant-animal interactions that are sometimes not yet recognized for their extant relatives. The dietary preferences of short-proboscid nemestrinids are unknown, and pollinivory has not been recorded for extant Nemestrinidae.3 We analyzed the contents of the conspicuously swollen abdomen of an ca. 47.5 Ma old nemestrinid fly of the genus Hirmoneura from Messel, Germany, with photogrammetry and state-of-the-art palynological methods. The fly fed on pollen from at least four plant families-Lythraceae, Vitaceae, Sapotaceae, and Oleaceae-and presumably pollinated flowers of two extant genera, Decodon and Parthenocissus. We interpret the feeding and foraging behavior of the fly, reconstruct its preferred habitat, and conclude about its pollination role and importance in paratropical environments. This represents the first evidence that short-proboscid nemestrinid flies fed, and possibly feed to this day, on pollen, demonstrating how fossils can provide vital information on the behavior of insects and their ecological relationships with plants.

Newly discovered fossil bugs (Insecta: Hemiptera: Heteroptera: Pentatomidae) from the Eocene of Messel (Germany) and Green River (North America) exhibit an exaggerated morphology including prominent spiny humeral and anterolateral angles of the pronotum and a spiny lateral abdominal margin. Especially the humeral angles are unique; they consist of expansive, rounded projections with strong spines, which is a rare trait among pentatomids. A hypothesis for the function of this extreme morphology is defence against small vertebrate predators, such as birds or reptiles. The same protuberances also produce a disruptive effect camouflaging the specimen in its environment and provide additional protection. Therefore, the extreme morphology provides primary as well as secondary anti-predator defence. The morphology of Eospinosus peterkulkai gen. et sp. nov. and E. greenriverensis sp. nov. resembles that of Triplatygini, which today occur exclusively in Madagascar, as well as that of Discocephalinae or Cyrtocorinae, which today occur in the Neotropics. Due to a lack of conclusive characters, it cannot be excluded that the fossil species may represent a case of remarkable convergence and are not related to either taxon. Phylogenetic analyses using parsimony as well as Bayesian algorithms confirmed that the new genus is a member of Pentatomidae, but could not solve its phylogenetic relationships within Pentatomidae.

Archaeomalthus synoriacos gen. et sp. nov. from the Upper Permian Babiy Kamen` locality indicates a remarkable evolutionary stability. Herein we report the oldest record of the family Micromalthidae, Archaeomalthus synoriacos gen. et sp. nov., which demonstrates several plesiomorphic character states, but generally retains most of the apomorphies of Micromalthidae. Archaeomalthus suggests that a distinct simplification of the morphology of adults already evolved in the late Paleozoic, suggesting and early reduction of the role of adults in the life cycle of the group. Despite the marked differences between Archaeomalthus and Micromalthus, the former already show a distinct and apparently very stable degree of deviation from the ground plan of Coleoptera s.str. and s.l. The remarkable series of reductional features shared by the Permian fossil and the extant species include a lightly sclerotized body without distinct surface sculpture, a head lacking dorsal protuberances, shortened and apparently thin elytra, exposed membranous areas behind the procoxae and between at least two basal visible abdominal sternites, and the reversal of the invagination of the terminal abdominal segments. It is likely that the reduced role of adults of Micromalthidae was a syndrome of simplified, vestigial adult morphology characters acquired at least 255 million years ago.

Cephalic features of Micromalthus debilis were examined and described in detail for the first time. The head displays several seemingly plesiomorphic features compared to other extant species of Archostemata, especially representatives of Cupedidae and Ommatidae. Cephalic protuberances characteristic for species of these two families are missing and antennal grooves are also absent. The surface of the head capsule is largely smooth, without the characteristic tubercles found in stemgroup beetles and ommatid and cupedid species. Cuticular scales, probably ancestral for Archostemata and possibly for Coleoptera, are also completely absent. The arrangement of three mandibular teeth in a vertical row and an immobilized labrum are derived features shared with Ommatidae. The maxillary endite lobes are absent, as in the very small Crowsoniella relicta (Crowsoniellidae). Like in all other examined archostematan species, mandibular molae and prosthecae are missing. The simplified maxillae apparently play no role in the food uptake but rather function as accessory "ventral antennae". Derived features include the partly reduced maxillary musculature and lack of extrinsic labial muscles. Apomorphies of the digestive tract include the sclerotized median protuberances of the anterior epipharynx and hypopharynx, and the presence of a vertical anterior pharyngeal loop and a subcerebral postpharyngeal pouch. The tentorium is strongly reduced. Consequently, all antennal muscles originate from the head capsule. A very unusual and possibly plesiomorphic feature is the presence of a short salivary tube and two associated muscles. This is a unique condition in Coleoptera as far as known at present. Structural features suggest that Micromalthus probably feeds on wood infested with fungi. A robust phylogenetic evaluation of anatomical features is presently not possible due to the lack of data for Crowsoniella (Crowsoniellidae) and Sikhotealinia zhiltzovae (Jurodidae). Moreover, phylogenetic and evolutionary interpretations are impeded by possible effects of vestigialization of adults possibly resulting from endosymbionts (e.g. Wolbachia, Rickettsiales)

The structure of insect wing articulation is considered as reliable source of high level characters for phylogenetic analyses. However, the correct identification of homologous structures among the main groups of Pterygota is a hotly debated issue. Therefore, the reconstruction of the wing bases in Paleozoic extinct relatives is of great interest, but at the same time it should be treated with extreme caution due to distortions caused by taphonomic effects. The present study is focused on the wing base in Dunbaria (Spilapteridae). The articulation in Dunbaria quinquefasciata is mainly formed by a prominent upright axillary plate while the humeral plate is markedly reduced. Due to unique preservation of surface relief of the axillary plate, its composition shows a detailed pattern of three fused axillary sclerites and presumable position of the sclerite 3Ax. The obtained structures were compared among Spilapteridae and to other palaeodictyopterans Ostrava nigra (Homoiopteridae) and Namuroningxia elegans (Namuroningxiidae). The comparative study uncovered two patterns of 3Ax in Dunbaria and Namuroningxia, which correspond to their different suprafamilial classification. In contrast to previous studies these new results reveal the homologous structural elements in the wing base between Paleozoic Palaeodictyoptera and their extant relatives of Ephemeroptera, Odonata and Neoptera.

A history of the Marine Zoology Department at the Senckenberg Society for the Study of Nature (Senckenbergische Naturforschende Gesellschaft) has not yet been published. Still, there is no lack of documentation of research activities at the Senckenberg Research Institute and Natural History Museum. Marine zoology studies began with Eduard Rüppell (1794–1884) after his admission to the Senckenberg Society in 1818, one year after its foundation, and his collections of fishes, molluscans and crustaceans from the Mediterranean made in 1820. During the nineteenth century, further progress in marine zoology studies was slow and serious interest in the study of marine organisms expanded significantly only during the twentieth century after the foundation of the marine station at Wilhelmshaven in 1928. The amount of marine biology and geology literature originating from researchers associated with the Senckenberg has become overwhelming and the dwarfs once standing on the shoulder of giants have become giants themselves. In this article, we present the Marine Zoology Department, its sections and assess the most important researchers associated with the Senckenberg Research Institute including the founders of the sections and their place in two centuries of history since the foundation of the Senckenberg Society in 1817.

The Specialized Information Service Biodiversity Research (BIOfid; http://biofid.de/) has recently been launched to mobilize valuable biodiversity data hidden in German print sources of the past 250 years. The partners involved in this project started digitisation of the literature corpus envisaged for the pilot stage and provided novel applications for natural language processing and visualization. In order to foster development of new text mining tools, the Senckenberg Biodiversity Informatics team focuses on the design of ontologies for taxa and their anatomy. We present our progress for the taxa prioritized by the target group for the pilot stage, i.e. for vascular plants, moths and butterflies, as well as birds. With regard to our text corpus a key aspect of our taxonomic ontologies is the inclusion of German vernacular names. For this purpose we assembled a taxonomy ontology for vascular plants by synchronizing taxon lists from the Global Biodiversity Information Facility (GBIF) and the Integrated Taxonomic Information System (ITIS) with K.P. Buttler’s Florenliste von Deutschland (http://www.kp-buttler.de/florenliste/). Hierarchical classification of the taxonomic names and class relationships focus on rank and status (validity vs. synonymy). All classes are additionally annotated with details on scientific name, taxonomic authorship, and source. Taxonomic names for birds are mainly compiled from ITIS and the International Ornithological Congress (IOC) World Bird List, for moths and butterflies mainly from GBIF, both lists being classified and annotated accordingly. We intend to cross-link our taxonomy ontologies with the Environment Ontology (ENVO) and anatomy ontologies such as the Flora Phenotype Ontology (FLOPO). For moths and butterflies we started to design the Lepidoptera Anatomy Ontology (LepAO) on the basis of the already available Hymenoptera Anatomy Ontology (HAO). LepAO is planned to be interoperable with other ontologies in the framework of the OBO foundry. A main modification of HAO is the inclusion of German anatomical terms from published glossaries that we add as scientific and vernacular synonyms to make use of already available identifiers (URIs) for corresponding English terms. International collaboration with the founders of HAO and teams focusing on other insect orders such as beetles (ColAO) aims at development of a unified Insect Anatomy Ontology. With a restriction on terms applicable on all insects the unified Insect Anatomy Ontology is intended to establish a basis for accelerating the design of more specific anatomy ontologies for any particular insect order. The advancement of such ontologies aligns with current needs to make knowledge accumulated in descriptive studies on the systematics of organisms accessible to other domains. In the context of BIOfid our ontologies provide exemplars on how semantic queries of yet untapped data relevant for biodiversity studies can be achieved for literature in non-English languages. Furthermore, BIOfid will serve as an open access platform for professional international journals facilitating non-commercial publishing of biodiversity and biodiversity-related data.

New morphological techniques allow for the evaluation of novel character systems that are potentially important for phylogenetic analysis. Only a few studies so far have used character systems from the insect thorax for phylogenetics; the reasons for this might include a lack of common terminology or established homology for pterygote insect thorax musculature. Still, recent studies have proposed common terminology and hypotheses of homology, now allowing for an evaluation of thoracic morphological character systems among the groups of winged insects. Using X-ray microtomography (CT) we present a detailed study of the thorax musculature of Odonata as an important phylogenetic character system, with a matrix of 298 characters with 697 character states, including novel data from the thoracic anatomy of eight damselfly larvae. We also included additional Odonata, Ephemeroptera and Neoptera taxa from the literature and demonstrate the phylogenetic relevance of this character system by reproducing phylogenetic topologies of established relationships. We also compared high-resolution data from Odonata larvae from our study and from recent literature with data from older literature in the adult Odonata. All major clades were successfully recovered, (e.g. Odonata, Epiprocta, Anisoptera and Zygoptera) with high node support, but obtained higher phylogenetic resolution with the larval data. The best phylogenetic resolution was achieved by combining the adult and larval characters. The taxon sampling and character matrix is the largest to date and underlines the potential relevance of the thorax musculature as an important phylogenetic character system.

BIOfid is a specialized information service currently being developed to mobilize biodiversity data dormant in printed historical and modern literature and to offer a platform for open access journals on the science of biodiversity. Our team of librarians, computer scientists and biologists produce high-quality text digitizations, develop new text-mining tools and generate detailed ontologies enabling semantic text analysis and semantic search by means of user-specific queries. In a pilot project we focus on German publications on the distribution and ecology of vascular plants, birds, moths and butterflies extending back to the Linnaeus period about 250 years ago. The three organism groups have been selected according to current demands of the relevant research community in Germany. The text corpus defined for this purpose comprises over 400 volumes with more than 100,000 pages to be digitized and will be complemented by journals from other digitization projects, copyright-free and project-related literature. With TextImager (Natural Language Processing & Text Visualization) and TextAnnotator (Discourse Semantic Annotation) we have already extended and launched tools that focus on the text-analytical section of our project. Furthermore, taxonomic and anatomical ontologies elaborated by us for the taxa prioritized by the project’s target group - German institutions and scientists active in biodiversity research - are constantly improved and expanded to maximize scientific data output. Our poster describes the general workflow of our project ranging from literature acquisition via software development, to data availability on the BIOfid web portal (http://biofid.de/), and the implementation into existing platforms which serve to promote global accessibility of biodiversity data.

BACKGROUND:The understanding of concerted movements and its underlying biomechanics is often complex and elusive. Functional principles and hypothetical functions of these complex movements can provide a solid basis for biomechanical experiments and modelling. Here a description of the cephalic anatomy of Pyrrhosoma nymphula (Zygoptera, Coenagrionidae) focusing on functional aspects of the mouthparts using micro computed tomography (μCT) is presented.RESULTS:We compared six different instars of the damselfly P. nymphula as well as one instar of the dragonfly Aeshna cyanea and Epiophlebia superstes each. In total 42 head muscles were described with only minor differences of the attachment points between the examined species and the absence of antennal muscle M. scapopedicellaris medialis (0an7) in Epiophlebia as a probable apomorphy of this group. Furthermore, the ontogenetic differences between the six larval instars are minor; the only considerable finding is the change of M. submentopraementalis (0la8), which is dichotomous in the early instars (I1,I2 and I3) with a second point of origin at the postero-lateral base of the submentum. This dichotomy is not present in any of the older instars studied (I6, middle-late and pen-ultimate).CONCLUSION:However, the main focus of the study herein, is to use these detailed morphological descriptions as basis for hypothetic functional models of the odonatan mouthparts. We present blueprint like description of the mouthparts and their musculature, highlighting the caused direction of motion for every single muscle. This data will help to elucidate the complex concerted movements of the mouthparts and will contribute to the understanding of its biomechanics not in Odonata only.

The appearance of wings in insects, early in their evolution [1], has been one of the more critical innovations contributing to their extraordinary diversity. Despite the conspicuousness and importance of wings, the origin of these structures has been difficult to resolve and represented one of the "abominable mysteries" in evolutionary biology [2]. More than a century of debate has boiled the matter down to two competing alternatives-one of wings representing an extension of the thoracic notum, the other stating that they are appendicular derivations from the lateral body wall. Recently, a dual model has been supported by genomic and developmental data [3-6], representing an amalgamation of elements from both the notal and pleural hypotheses. Here, we reveal crucial information from the wing pad joints of Carboniferous palaeodictyopteran insect nymphs using classical and high-tech techniques. These nymphs had three pairs of wing pads that were medially articulated to the thorax but also broadly contiguous with the notum anteriorly and posteriorly (details unobservable in modern insects), supporting their overall origin from the thoracic notum as well as the expected medial, pleural series of axillary sclerites. Our study provides support for the formation of the insect wing from the thoracic notum as well as the already known pleural elements of the arthropodan leg. These results support the unique, dual model for insect wing origins and the convergent reduction of notal fusion in more derived clades, presumably due to wing rotation during development, and they help to bring resolution to this long-standing debate.

In order to promote the accessibility of biodiversity data in historic and contemporary literature, we introduce a new interdisciplinary project called BIOfid (FID=Fachinformationsdienst, a service for providing specialized information). The project aims at a mobilization of data available in print only by combining digitization of scientific biodiversity literature with the development of innovative text mining tools for complex, eventually semantic searches throughout the complete text corpus. A major prerequisite for the development of such search tools is the provision of sophisticated anatomy ontologies on the one hand, and of complete lists of species names (currently considered valid as well as all synonyms) at a global scale on the other hand. In the initial stage, we chose examples from German publications of the past 250 years dealing with the geographic distribution and ecology of vascular plants (Tracheophyta), birds (Aves), as well as moths and butterflies (Lepidoptera) in Germany. These taxa have been prioritized according to current demands of German research groups (about 50 sites) aiming at analyses and modeling of distribution patterns and their changes through time. In the long term, we aim at providing data and open source software applicable for any taxon and geographic region. For this purpose, a platform for open access journals for long-term availability of professional e-journals will be established. All generated data will also be made accessible through GFBio (German Federation for Biological Data). BIOfid is supported by the LIS-Scientific Library Services and Information Systems program of the German Research Foundation (DFG).

A protocol using insect specimens or parts thereof allows for sequencing of sections of nuclear 28S rDNA. In the present note it is demonstrated that this protocol can readily be applied to strongly degraded DNA (ancient, fixed or contaminated). Primers that are specifically designed to discriminate against human DNA but also other non‐arthropod species are tested on a range of species covering all insect groups (59 insect species from all 33 orders). Additionally, the samples represent a selection of various, mostly DNA‐degrading, preservation methods, including the most common fixatives used for morphological investigations and for long‐term storage in collections. Successful amplification was possible for all tested samples including ca . 200 year‐old dried museum specimens as well as for over 4000 year‐old fossil insects embedded in copal. When the NCBI database contained information on the tested species an unambiguous taxonomic discrimination was possible. This approach is based on a standardized protocol that guarantees easy application. This note presents primer pairs for 28S rDNA that can be a useful tool for ancient DNA (aDNA) research.

The discovery of a new megasecopteron, Brodia jogginsensis sp. nov., is reported from the Joggins Formation, a UNESCO World Heritage Site in Nova Scotia, Canada. The new species diagnosis is based on the unique pattern of hind wing venation bearing three anterior branches of MP and pectinate CuP with four posterior branches. Its occurrence in Langsettian deposits of the Maritimes Basin correspond well with other Pennsylvanian Brodiidae known from the Coal Measures of the UK and Mazon Creek in Illinois, USA. Based on our re-examination, we propose to transfer the genus Pyebrodia, with P. martinsnetoi Brauckmann & Herd, 2003, described as a putative member of Brodiidae, into Palaeodictyoptera family incertae sedis as it lacks most of the diagnostic features of Brodiidae. The holotype of Eubrodia dabasinskasi Carpenter, 1967, housed in a private collection, was supplemented by the description of an additional specimen housed in The Field Museum, Chicago. The fossil record of Brodiidae is reviewed and additional remarks concerning the wing morphology and the function of specialized structures, such as reinforcements in the form of a specialized crossvein between A1 and CuP, are given. Putative nymphs of Brodiidae and development of wings in Megasecoptera are discussed.http://zoobank.org/urn:lsid:zoobank.org:pub:741846CB-FAD0-4103-90D3-2896D8909E94

A new palaeodictyopterid nymph Bizarrea obscura gen. n.etsp. n. (Spilapteridae) and a new adult specimen of Homaloneura cf. dabasinskasi Carpenter are described from the Pennsylvanian (Moscovian) ironstone nodules of Mazon Creek (IL, U.S.A.). Both taxa share enlarged prothoracic lobes (interpreted by some as winglets), heteronomous meso- and metathoracic wing pads or wings, a slender abdomen with pointed laterotergites, and a unique division of the abdominal segments by two transverse sulci. An alternative hypothesis for the placement of Bizarrea within Homoiopteridae is considered on the basis of its large body size and relatively short wing pads. Based on the morphology of the new material, postembryonic development of wing pads in Palaeodictyoptera (Palaeodictyopterida) is reconsidered. Detailed investigation of the abdominal segments, including examination by scanning electron microscopy, reveals the presence of subcircular, sclerotized structures partially covered at the bases of the nymphal laterotergites I- VII VIII. Based on their position and shape, these structures are interpreted as abdominal spiracles, and thus a terrestrial or semiaquatic habitat for these immatures is hypothesized. Moreover, our discovery of the same, supposedly homologous structures in the enigmatic Vogesonymphidae (Permoplectoptera), from the Middle Triassic of Grss Voltzia in France, is evidence for the parallel coexistence of ancestrally terrestrial and derived aquatic lineages of Ephemerida (Ephemeropterida) in early Mesozoic ecosystems.

Spermatozoa provide an unusual character system, with a limited number of components organized in a single cell. Similar spermatozoa occur in groups widely separated in the phylogenetic tree of Metazoa. Nevertheless, the character system contains phylogenetic information. Hexapoda have acquired spermatophores along with the switch from aquatic to terrestrial habitats, and related to this, a multitude of different sperm types. The aim of this study is a formal evaluation of the phylogenetic information content of spermatozoa. For the first time, sperm characters are coded for formal phylogenetic analyses. Different approaches are used and compared. Mainly due to a high level of homoplasy, the evaluation of sperm characters alone is insufficient for a reconstruction of the phylogeny of the group. Yet, a reliable reconstruction of the evolution of insect sperm is possible when character transformations are assessed using a phylogeny based on extensive molecular data. Important changes took place in the early evolution of Hexapoda. Sperm characters support some major clades (e.g. Hexapoda, Dicondylia, Polyneoptera, Psocodea), but important steps in the evolution are not reflected by transformations of spermatozoa, notably the rise of Pterygota or Holometabola. Important innovations are the formation of mitochondrial derivatives and the acquisition of accessory microtubules. Some features are conservative, whereas others evolved rapidly (e.g. presence or absence of the acrosome vesicle). Some groups are conservative in their sperm features (e.g. Odonata, Heteroptera), whereas the evolution of spermatozoa was distinctly accelerated in others (e.g. Ephemeroptera). The rate of evolution can change drastically in closely related groups. Profound changes in the morphologically uniform Zoraptera underline that sperm evolution can follow a pattern very different from the general somatic morphology. The mode of character reconstruction preferred here will be useful for the evaluation of specialized morphological character systems and strengthen the concept of evolutionary morphology.

Background: Secondary winglessness is a common phenomenon found among neopteran insects. With an estimated age of at least 140 million years, the cave crickets (Rhaphidophoridae) form the oldest exclusively wingless lineage within the long-horned grasshoppers (Ensifera). With respect to their morphology, cave crickets are generally considered to represent a 'primitive' group of Ensifera, for which no apomorphic character has been reported so far.Results: We present the first detailed investigation and description of the thoracic skeletal and muscular anatomy of the East Mediterranean cave cricket Troglophilus neglectus (Ensifera: Rhaphidophoridae). T. neglectus possesses sternopleural muscles that are not yet reported from other neopteran insects. Cave crickets in general exhibit some unique features with respect to their thoracic skeletal anatomy: an externally reduced prospinasternum, a narrow median sclerite situated between the meso-and metathorax, a star-shaped prospina, and a triramous metafurca. The thoracic muscle equipment of T. neglectus compared to that of the bush cricket Conocephalus maculatus (Ensifera: Tettigoniidae) and the house cricket Acheta domesticus (Ensifera: Gryllidae) reveals a number of potentially synapomorphic characters between these lineages.Conclusions: Based on the observed morphology we favor a closer relationship of Rhaphidophoridae to Tettigoniidae rather than to Gryllidae. In addition, the comparison of the thoracic morphology of T. neglectus to that of other wingless Polyneoptera allows reliable conclusions about anatomical adaptations correlated with secondary winglessness. The anatomy in apterous Ensifera, viz. the reduction of discrete direct and indirect flight muscles as well as the strengthening of specific leg muscles, largely resembles the condition found in wingless stick insects (Euphasmatodea), but is strikingly different from that of other related wingless insects, e.g. heel walkers (Mantophasmatodea), ice crawlers (Grylloblattodea), and certain grasshoppers (Caelifera). The composition of direct flight muscles largely follows similar patterns in winged respectively wingless species within major polyneopteran lineages, but it is highly heterogeneous between those lineages.

Serial cross sections (80 nm) and an image stack (353 sections) of the head of the extremely miniaturized first instar larvae of Stylops ovinae (Stylopidae) were obtained with serial block-face scanning electron microscopy. This approach made it possible for the first time to reconstruct the head anatomy of a strepsipteran larva precisely, partly to cell level. The cephalic anatomy is described in detail, based on a 3D-reconstruction. It was possible to show the proportions of the exoand endocuticle and the epidermis. Endoskeletal structures are the pharyngeal skeleton and the anterior tentorial arms, which form an articulation with the mandibles. The dorsoventrally flattened mandibles are the only functional mouthparts and used for penetrating the host’s cuticle. The maxillae are fused with the head capsule to form the ventral plate, and the strongly modified and reduced labium functions as a closure of the ventral head opening. The nerves ending at the anterior head margin were reconstructed. The innervation of setae, olfactory pits and the vestigial maxillary palps are also documented for the first time. Five fat body cells are located in the head. Antennae, hypopharynx and labrum are not present as defined structures. A structure resembling a labrum is a secondary formation. Only nine cephalic muscles are present. Muscles of the antennae, hypopharynx, labrum and maxillae are missing. Some of the muscles originate in the thorax. Homology issues, possible phylogenetic implications, functional aspects of head structures, and also possible correlations of structural features with miniaturization and parasitism are discussed.