372 Accepted by J. Morse: 11 Feb. 2019; published: 20 Mar. 2019 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2019 Magnolia Press Zootaxa 4568 (2): 372–382 https://www.mapress.com/j/zt/ Article https://doi.org/10.11646/zootaxa.4568.2.11 http://zoobank.org/urn:lsid:zoobank.org:pub:6872C9B3-7E70-4EE2-BF8B-31E032BFE45D The larva of Plectrocnemia renetta Malicky 1975 (Trichoptera, Polycentropodidae), including a discriminatory matrix to the larvae of Plectrocnemia Stephens 1836 species of Greece JOHANN WARINGER 1,3 & HANS MALICKY 2 1 Department of Limnology and Bio-Oceanography, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 2 Sonnengasse 13, A- 3293 Lunz am See, Austria 3 Corresponding author. E-mail: johann.waringer@univie.ac.at Abstract This paper describes the previously unknown larva of Plectrocnemia renetta Malicky 1975. Information on the morpho- logy of the final instar larva is given and the most important diagnostic features are illustrated. A preliminary discrimina- tory matrix for the Greek larvae of Plectrocnemia Stephens 1836 is also provided. Plectrocnemia renetta and P. conspersa conspersa (Curtis 1834) belong to the group where the inner and outer dorsal secondary setae on abdominal segment IX are strongly different in length. These two species can be separated from each other by the arrangement of muscle attach- ment spots on the head capsule, number and length of setae on abdominal sternum IX, and by distribution patterns. With respect to zoogeography, Plectrocnemia renetta has been reported from Cyprus, Turkey, and from the Greek islands of Ikaria and Samos. Key words: final instar, identification, key, discriminatory matrix, distribution, caddisfly Introduction The polycentropodid genera Holocentropus McLachlan 1878, Plectrocnemia Stephens 1836, Polycentropus Curtis 1835, and Polyplectropus Ulmer 1905 are only weakly defined and various species have been shifted from time to time among them. For many years, New World workers synonymized these genera and included all their species in Polycentropus. An in-depth phylogenetic analysis was performed on the genera of Polycentropodidae by Chamorro & Holzenthal (2011). Based on their findings, they recommended the transfer or re-instatement of the species to their respective genera. To unite these genera again into only one large genus Polycentropus would cause serious nomenclatorial confusion, so we prefer to leave the now-well-established names as they are. Of the 97 extant species included in the genus Plectrocnemia, 48 species are recorded from the Oriental, 22 from the West Palearctic, 19 from the East Palearctic, and 8 species from the Australasian Biogeographic Regions (Morse et al. 2012, Morse 2018). Twenty European species of Plectrocnemia Stephens 1836 are listed in the ‘Distribution Atlas of European Trichoptera’ (Neu et al. 2018); apart from the nominate subspecies, the European inventory also includes one subspecies of P. conspersa (Curtis 1834) and four subspecies of P. geniculata McLachlan 1871 (Malicky 2004, 2005a; Graf et al. 2008). So far, we are aware of larval descriptions of 5 European species only: Plectrocnemia brevis McLachlan 1871, the nominate subspecies of P. conspersa, the nominate subspecies of P. geniculata, P. laetabilis McLachlan 1880, and P. latissima Martynov 1913 (Lepneva 1964; Wallace & Wallace 1983; Edington & Hildrew 1995; Viera-Lanero 2000, Viera-Lanero et al. 2009; Waringer & Graf 2011, 2013). With respect to Greek Plectrocnemia species, the widespread taxa P. brevis, P. c. conspersa, and P. g. geniculata are known in the larval stage, whereas the larvae of P. conspersa keftiu Malicky 1974, P. kydon Malicky 1974, P. mojkovacensis Malicky 1982, and P . renetta Malicky 1975 are unknown. Material collected by Hans Malicky during his expeditions in the Mediterranean area has now enabled the larval description of P . renetta.