The return of the Duke-locality data for Megadytes ducalis Sharp, 1882, br />the world's largest diving beetle, with notes on related species (Coleoptera: Dytiscidae).

Megadytes (Bifurcitus) ducalis Sharp, 1882 is the largest diving beetle in the world and has been considered a candidate for the world's rarest insect (Jones 2010). It was described from "Brazil", is only known from the male holotype in the Natural History Museum (London), and typically thought to be extinct. Here we report the finding of 10 additional specimens, all collected at the end of the 19th century, which were discovered incidentally in different historical collections, including drawers with unsorted diving beetle accessions of the Muséum National d'Histoire Naturelle (Paris). These specimens, whilst old, reveal exact locality data for the first time, enabling focused field campaigns to attempt to rediscover this giant alive. Locality labels all indicate Santo Antônio da Barra (present name Condeúba), in the southern part of Bahia, Brazil, suggesting that the species may have a restricted distribution in wetter parts of the Brazilian savanna or cerrado. We also describe the female of M. ducalis for the first time and present new records of the putatively closely related species Megadytes magnus Trémouilles Bachmann, 1980 and M. lherminieri (Guérin-Méneville, 1829), the latter being recorded for the first time from Ecuador. These three morphologically similar species together form the subgenus Bifurcitus Brinck, 1945 and we provide photographs of their habitus, median lobes and other morphological details.

Copelatus Erichson from the Dominican Republic, with the description of a new species, comments on elytral striation and faunistic notes on Antillean species (Coleoptera: Dytiscidae: Copelatinae).

The species of the genus Copelatus Erichson, 1832 occurring in the Dominican Republic are reviewed. Five species are recorded, with recent collecting data provided for four of them. Copelatus martini sp. nov., a member of the consors species group, is described and illustrated. It is compared to the apparently similar species C. guadelupensis Legros, 1948 based on morphological characters and on partial sequences of the CO1 gene. Interesting cases of intraspecific variability in the number of elytral dorsal striae in C. martini sp. nov. and C. vitraci are discussed in the light of the traditional taxo-nomic importance of this character for species group delimitation in Copelatus. Copelatus caelatipennis Aubé, 1838 and C. vitraci Legros, 1948 are recorded for the first time from the Dominican Republic (and therefore also from Hispaniola Island). The remaining species are C. posticatus (Fabricius, 1801), and C. insolitus Chevrolat, 1863 (for the latter, pre-sence in Hispaniola is doubtful and requires confirmation). Finally, C. guadelupensis is recorded from Puerto Rico for the first time, and a checklist of the Copelatus species of the Antilles is appended.

The genus Notomicrus in Guadeloupe, with description of three new species (Coleoptera: Noteridae).

The genus Notomicrus Sharp, 1882 is recorded from Guadeloupe for the first time. Examination of recently collected material revealed the presence of four species, of which three are described as new species so far endemic to Guadeloupe. Notomicrus sabrouxi sp. n. is akin to the continental Neotropical species N. gracilipes Sharp, 1882 and N. traili Sharp, 1882. Notomicrus chailliei sp. n. and N. femineus sp. n. are sibling species which diverge from each other by 3.4% of observed distance in cytochrome oxidase 1 sequences. The latter species seems to be comprised of only females, and is suspected to reproduce by obligate parthenogenesis. The fourth species is N. sharpi Balfour-Browne, 1939. These species are morphologically described notably through scanning electron microscopy study, and data on their distribution in the Guadeloupe archipelago and habitat preferences are presented and discussed.