Immature stages of Palearctic Mecinus species (Coleoptera, Curculionidae, Curculioninae): morphological characters diagnostic at genus and species levels Author Gosik, Rafal Department of Zoology and Nature Protection, Maria Curie-Sklodowska University, Akademicka 19, 20 - 033 Lublin, Poland Author Skuhrovec, Jiri Group Function of Invertebrate and Plant Biodiversity in Agro-Ecosystems, Crop Research Institute, Prague 6 - Ruzyne, Czech Republic https://orcid.org/0000-0002-7691-5990 jirislavskuhrovec@gmail.com Author Caldara, Roberto Center of Alpine Entomology, University of Milan, Via Celoria 2, 20133 Milan, Italy Author Tosevski, Ivo CABI, Rue des Grillons 1, 2800 Delemont, Switzerland & Institute for Plant Protection and Environment, Banatska 33, 11080, Zemun, Serbia text ZooKeys 2020 939 87 165 http://dx.doi.org/10.3897/zookeys.939.50612 journal article http://dx.doi.org/10.3897/zookeys.939.50612 1313-2970-939-87 B239701148884712880E1069C943AD33 DB6D50A55057576896F6AFDAE5BC9922 Mecinus pascuorum group Differential diagnosis. Larva. (1) cuticle of the body tuberculate; (2) pedal lobes prominent, clearly distinct; (3) abdominal segment X reduced to three anal lobes; (4) thoracic spiracle unicameral; (5) abdominal setae various in length, progressively longer from abdominal segment I to VIII; (6) abdominal segments I-VIII with four pds and two ss ; (7) head white, rounded; (8) frontal suture weakly visible; (9) endocarina 4/5 length of frons; (10) des4 short; (11) presence of fs1 ; (12) absence of fs2 ; (13) fs3 very short; (14) head with one stemma; (15) absence of cls1 ; (16) labial palpi one-segmented; (17) premental sclerite cup-like, posterior extension with short, dull apex; (18) surface of postlabium smooth. Pupa. (1) body stout, rather short; (2) urogomphi short; (3) rostrum moderately slender; (4) setae various in length; (5) head with one os ; (6) rostrum with one or two rs ; (7) pronotum with two as , without or with one ds , two ls , three pls ; (8) meso- and metanotum with two setae; (9) abdominal segments I-VII with two or three setae dorsally and three minute setae ventrally. Remarks and comparative notes. The adults of this assemblage of several taxa are mostly very similar to each other, but, lacking synapomorphies, they were treated by Caldara et al. (2013) as a "complex" of species. Overall, they are characterised by small size (length shorter than 2.5 mm), usually with short, oval elytra, and with integument, at least in part, reddish. The larvae also have a combination of characters that distinguish them from those of the other groups, although with no clear autapomorphies. In contrast, the pupae are unique in having abdominal segments I-VII with 2-3 setae dorsally and three minute setae ventrally. Therefore, we can consider these species as an informal group like the other species groups.