Copelatus Erichson, 1832 from Maharashtra, India, with description of three new species and notes on other taxa of the genus (Coleoptera: Dytiscidae: Copelatinae).

The Copelatus species occurring in Maharashtra State, India, are reviewed. Altogether, nine species are recorded, three of which are described as new: Copelatus deccanensis sp. nov. (C. nigrolineatus species group), C. maushomi sp. nov. (C. consors group) and C. bezdeki sp. nov. (C. irinus group). Habitus and male genitalia are illustrated for all Copelatus species from Maharashtra, a key to the species and distribution maps are presented. New distributional records along with short diagnoses of already known species are provided. In addition, the study of extensive material of Copelatus species from the Indian subcontinent outside Maharashtra revealed the following new synonymies: Copelatus freudei Guignot, 1955 = C. gibsoni Vazirani, 1974 syn. nov. = C. gibsoni Vazirani, 1975 syn. nov. = C. spangleri Vazirani, 1974 syn. nov. = C. spangleri Vazirani, 1975 syn. nov.; Copelatus oblitus Sharp, 1882 = C. karnatakus Holmen Vazirani, 1990 syn. nov.; C. sociennus J. Balfour-Browne, 1952 = C. bangalorensis Vazirani, 1970 syn. nov.; Copelatus tenebrosus Régimbart, 1880 = C. ceylonicus Vazirani, 1969 syn. nov. = C. assamensis Vazirani, 1970 syn. nov.

Illustrated redescription of Haliplus (Liaphlus) arrowi Guignot, 1936 (Coleoptera: Haliplidae) from the Western Ghats, India, and notes on the closely related H. angustifrons Régimbart, 1892.

In an ongoing survey of aquatic beetles, the crawling water beetles Haliplus (Liaphlus) arrowi Guignot, 1936 and Haliplus (Liaphlus) angustifrons Régimbart, 1892 were found only from four (three localities for H. arrowi and one locality for H. angustifrons) out of 85 localities sampled in and around the Western Ghats of Maharashtra. Digital images and scanning electron micrographs of diagnostic characters are provided for the first time for both the species. Intraspecific and interspecific variation in the elytral maculation of H. arrowi and H. angustifrons is illustrated.