We describe a fossil hydrophilid beetle Anacaena paleodominica sp. nov. from the Early Miocene amber of the Dominican Republic, which is the only definitive amber inclusion of the family Hydrophilidae documented. The species belongs to the Recent Anacaena suturalis species group known from the Nearctic, Neotropical, and Australian regions. The fossil demonstrates that representatives of the species group may already have been widespread and common by the Early Miocene, and indicates a possible Miocene/post-Miocene extinction of the aquatic insect fauna on the island of Hispaniola.

In the present preliminary study we report an investigation on taxonomic status of individuals displaying diagnostic traits of intermediate values between the morphologically typical forms of Athous haemorrhoidalis (Fabricius 1801) and A. vittatus (Gmelin 1790) species occurring sympatrically. The presence of the “intermediate form” invoked the hypothesis of interspecific hybridization between A. haemorrhoidalis and A. vittatus species. An alternative explanation is that the “intermediate form” comprises individuals that are morphological variants of either of the species, without interspecific gene flow. We used partial sequences of two mitochondrial genes coding for the cytochrome oxidase subunit I (cox1) and 16S ribosomal RNA (rrnL), respectively. Additionally, we examined the variability of five polymorphic allozyme loci: 6Pgd, Idh, Mdh, Pgm and Gpi. Altogether, 28 A. haemorrhoidalis, 7 A. vittatus and 8 “intermediate form” individuals were included into the study. Phylogenetic analyses produced the trees of a consistent topology with high statistical support regardless of the method used. The specimens signified as the “intermediate form” constituted a monophyletic group with individuals of A. vittatus species. Empirical data confirmed that the reproductive isolation between the species studied is complete. No haplotype was shared between A. haemorrhoidalis and A. vittatus in sympatry. Similar results were obtained using the analysis of allozyme data. Especially at Idh and 6Pgd loci, alleles characteristic for A. vittatus and the “intermediate form” were not found in A. haemorrhoidalis, despite the larger sample examined. This suggests that the “intermediate form” is a phenotypic variant of A. vittatus without the signature of introgression.

A second species of michiakii species-group of Lycocerus Gorham is described, L. strictipennis sp. nov. (CHINA, Yunnan), and provided with illustrations of aedeagus. L. michiakii Okushima et Brancucci, 2008 is recorded from China for the first time. Habitus photos of both species are presented.

A new species of tigonopoid Platynotina (Atrocrates coconatae sp. nov.) is described, diagnosed and illustrated. An update for the key of the genus Atrocrates is proposed.

Basing on the newly described (Ectateus ursynowiensis Kamiński sp. nov.) and the type species a new taxonomical hypothesis of the genus Ectateus is proposed. Due to the rules of the International Code of Zoological Nomenclature following changes are made: designation of the lectotype for E. modestus (Fairmaire, 1887) and replacement name for the genus Cosmogaster Koch, 1956.

The species of Rodatus Mulsant are revised and illustrated. The following new synonyms are proposed: Rodatus bakewellii Crotch, 1874 [= Rodatus australis (Blackburn, 1889); Rodatus depressus Weise, 1895; Rhizobius subaustralis Blackburn, 1895]; Rodatus boucardi Crotch, 1874 [= Rodatus major (Blackburn, 1889); Rodatus crotchi (Blackburn, 1895)]. The lectotypes are designated for: Rhizobius australis Blackburn, Rhizobius crotchi Blackburn, Rhizobius discolor var.? proprius Blackburn, Rhizobius major Blackburn, Rhizobius nigronotatus Blackburn, Rhizobius ornatipennis Blackburn, Rhizobius subaustralis Blackburn. The following new species are described: Rodatus tasmanicus, R. marginalis, R. chaetonotus. The species of Rodatus are diagnosed and keyed. Nomenclatural history and distribution are provided for each species.

Henosepilachna niaki, sp. nov. from New Guinea is described and illustrated. Status of Henosepilachna Li, 1961 as a valid genus within the tribe Epilachnini is discussed.

Two larval instars of Quaestus (Quaesticulus) pachecoi (Bolivar, 1915) are described and illustrated for the first time. Chaetotaxy, morphology and measurements indicate that the Q. (Q.) pachecoi has a classic type of development with two instars only and larvae belong to a classic type according to the Deleurance-Glaçon classification.

Species of the genus Mimastra Baly, 1865 with unmodified first protarsomere in male and black or metallic bands on elytra are reviewed and keyed. Four new species are described as new to science: M. hsuehleeae sp. nov. (Taiwan), M. laotica sp. nov. (Laos), M. fouqueorum sp. nov. (Thailand) and M. schneideri sp. nov. (Thailand). Mimastra modesta Fairmaire, 1889, M. birmanica Bryant, 1954 and M. tenuelimbata Lopatin, 2004 are redescribed. Mimastra grahami Gressitt Kimoto, 1963 is resurrected from synonymy with M. malvi Chen, 1942. The status of Mimastra kremitovskyi Bezděk, 2009 is discussed. Colour photos of habitus, drawings of genitalia and identification key are presented.

Australodon gen. nov. is described for A. nearnsi sp. nov. from subtropical rainforests of the southern Queensland and northern New South Wales in Australia. Australodon belongs in Cerambycinae but it cannot be placed in any recognized tribe based on adult morphology; it is considered a genus incertae sedis, awaiting further research on higher classification of Cerambycinae. The males of Australodon have massive saber-tooth-like mandibles not frequent in other Cerambycinae members.

Socially parasitic and globally threatened Phengaris (=Maculinea) arion (L.) is one of the most intensively investigated insect species in Europe. Although current studies focus on ecology and genetics, the butterfly has also attracted attention because of its morphology. An extremely variable black pattern on the blue background of the wing upperside has resulted in the description of many different forms or even subspecies. We studied the variation of 148 individuals from five regional populations at a latitudinal gradient in Poland: two north-eastern populations, one middle-eastern populations and two southern populations. A proportion of the area covered with marginal strips and spots was measured, and the presence/absence of particular elements was also analyzed. For all except one, the most northern region, we found significant sexual dimorphism, with females being darker than males. Within sexes, the melanization level was higher in the north-east than in the south, and the mid — eastern region showed intermediate characteristics. Differences in colouration overlapped with variation in host ant use, but neither feature corresponded with the available genetic data and therefore clinal variation is a more likely explanation for the observed pattern. Melanization level may be an adaptation to climatic conditions, but it remains unclear which strategy of dorsal basking is applied by P. arion.

In this work we describe morphology and chaetotaxy of the first and last instars of three species of two genera (Apocheima Hübner and Lycia Hübner) of brachypterous moths which occur in Poland. Moreover, we discuss morphology and chaetotaxy of the last instar larva of Phigalia pilosaria (Denis & Schiffermüller, 1775). Head capsule and mouthparts are illustrated and described with the nomenclature of particular setae and pores. Chaetotaxy of thoracic legs and prolegs is provided. The shape and setal arrangement of anal plate are illustrated separately.

The Western Palaearctic species of the genus Caenophanes Foerster are reviewed. A new species from the Canary Islands, C. lapalmaensis sp. nov., is described. The name C. rugosifrons (Picard) is restored from synonymy (stat. resurr.). The redescriptions of C. incompletus (Ratzeburg) and C. rugosifrons are given. A key to the Western Palaearctic species of Caenophanes is suggested.

Three Chalcididae, namely Brachymeria ceratoniae Delvare sp. nov., Proconura persica sp. nov. and Psilochalcis ceratoniae Delvare sp. nov., are described from Iran. They were all reared from the carob moth Apomyelois ceratoniae (Lepidoptera: Pyralidae), the main pest of Ceratonia siliqua. Invreia subita Nikol'skaya, 1960 is formally transferred to the genus Psilochalcis. A lectotype is designated for Brachymeria confalonierii Masi, 1929.

A new species of Phytodietus Gravenhorst, 1829, Ph. (Weisia) pearlus sp. nov. from the Republic of South Africa is described and compared with congeneric Afrotropical species.

The socially-parasitic ant genus Strongylognathus is reported for Afghanistan for the first time, and a new species, S. kabakovi, is described based on the single queen. It belongs to the huberi species-group and is characterized by the small size. It differs from the latter species by the distinctly concave occipital margin, by the fines body sculpture, and by the less developed standing pilosity on the body.

Two new species of the family Oribotritiidae, Mesotritia solhoyi sp. nov. from Tibet, China and Oribotritia krivolutskyi sp. nov. from Azerbaijan, are described and illustrated. Mesotritia solhoyi is distinguished from the related species by the presence of one pair of anal setae, three pairs of adanal setae, and 8–10 pairs of long genital setae; weakly fusiform head of sensilli; rostral and lamellar setae situated at the same level. Oribotritia krivolutskyi is similar to O. submolesta, but differs by different number of lateral carinae; much longer aggenital setae; longer sensilli, interlamellar and lamellar setae; shorter notogastral setae; setae ps₂ and ps₃ thick and rigid; setae ad₂ placed more close to ad₃ than to setae ad₁, slightly different shape of sensilli.

The morphology of juvenile instars of the oribatid mites Neoliodes terrestris and N. ionicus (Neoliodidae) is described and illustrated. The juveniles of these two species are compared to those of other Neoliodes species. New diagnoses of the juvenile instars of Neoliodidae and Neoliodes are given. Identification keys to larvae and nymphs of Neoliodidae genera are presented.