Abstract This volume deals with North European species From Fennoscandia and Denmark are known 48 of the family Chloropidae, known as frit flies or genera and 209 species of frit flies: Rhodesiellinae chloropid flies, a large family of acalyptrate flies 1 species, Oscinellinae 111 species, Chloropinae 97 including some notarial, economically pests of ce- species. Among them 119 species are known from reals and fodder grasses. The taxonomy, biology Denmark, 97 from Norway, 189 from Sweden, 144 and faunistics of all NW European species are re- from Finland, and 115 from included provinces of vised. Keys are given to subfamilies, genera and Russia (Karelian Isthmus, Karelia, and the Kola species for the adults, for the larvae to generic level Peninsula). One new genus and 11 new species are as far as possible, and to specific level for a few ge- described, and some new synonyms and nomen- nera. Brief descriptions of the adult flies are given clatural changes are proposed. Some other new for all genera and species. Species distributions species, new synonyms, and overlooked specific in Fennoscandia and Denmark and elsewhere are names resulting from this revision have been pub- briefly outlined and further tabulated in a cata- lished earlier (Nartshuk, 1992, 1998, 1999, 2002a; logue. The known biology and ecology is summa- Nartshuk & Andersson, 2002; Nartshuk & Przhi- rized in general chapters and for each species. Il- boro, 2009; Nartshuk & Tschirnhaus, 2012). lustrations are given of the male genitalia and also of other characters of diagnostic importance. List of new taxa, synonyms and nomenclatural changes New taxa: Rhopalopterum tomentosum sp. nov. from North Colliniella gen. nov.; type species: Conioscinella mei- Sweden. jerei Duda, 1933. Restored from synonymy: Aphanotrigonum norrbotticum sp. nov. from North Oscinis ephippium Zetterstedt, 1848. Sweden. New synonyms: Calamoncosis halterata sp.nov.fromSweden. Aphanotrigonum brachypterum (Zetterstedt, 1848) Chlorops bjerkanderi sp.nov.fromSweden. = Aphanotrigonum trilineatum var. micropte- Conioscinella abiskoi sp.nov.fromNorthSweden. rum Duda, 1932. Conioscinella messaurea sp.nov.fromNorthSwe- Aphanotrigonum cinctellum (Zetterstedt, 1848) den. = Oscinis fasciella Zetterstedt, 1855. Conioscinella tornensis sp.nov.fromNorthSweden. Dicraeus nitidus Wahlgren, 1913 = Dicraeus na- Dicraeus tjederi sp. nov. from southern Sweden. paeus Collin, 1946. Eribolus danicus sp. nov. from Denmark and Swe- Eribolus slesvicensis Becker, 1910 = Eribolus cras- den. sipes Nartshuk, 1972. Gaurax norvegicus sp. nov. from Norway and Swe- Gaurax ephippium (Zetterstedt, 1848) = Gaurax den. strobilum Karps, 1981. Gaurax suecicus sp.nov.fromSweden. Trachysiphonella rufijiceps (Macquart, 1835) = Chlo- Lasiosina danielssoni sp.nov.fromGotland,Swe- rops pygmaeus Meigen, 1838 = Oscinis flavella den. Zetterstedt, 1848 = Siphonella diplotoxoides Meromyza bifurcata sp.nov.fromSweden. Strobl, 1893. 1 New combination and status: Aphanotrigonum trilineatum var. micropterum Microcercis kroeberi (Duda, 1933). Duda, 1932. Lectotype designations: Gaurax borealis Duda, 1933. Introduction The purpose of the present work is to present a re- first level consumers. Their role as pests of cere- vision of the species of Chloropidae or “frit flies” in als and cultivated grasses should also not be ne- a broad sense, also known as chloropid flies or grass glected. Increased abundance of certain species of flies, occurring in NW Europe with special empha- Chloropidae is used as a bioindicator that cereals sis on Denmark, Sweden, Norway, Finland and the and grasses are under environmental stress, e.g. adjacent Russian provinces of the Fennoscandian from draught or industrial pollution. Peninsula. It provides keys to subfamilies, genera The studies made in preparation of the present and species, descriptions of adult and larval mor- book had some spin-off in terms of descriptions phology, biology, and local and Palearctic distribu- of new species from Fennoscandia and Denmark, tion. Chloropidae is a large family of small aca- new synonymies, finds of overlooked names, and lyptrate flies usually 2.0–4.0 mm in length, excep- a proposal for conservation of a specific name tionally 5.0–8.0 mm. They are morphologically and (Nartshuk, 1992, 1998, 1999, 2002a, 2004; Nartshuk ecologically very diverse. The flies may be found in & Andersson, 2002). Still, not all taxonomical prob- practically all kinds of terrestrial habitats. Greatest lems concerning Scandinavian Chloropidae have diversity and abundance of species is usually found been settled with the present book. Especially the in open landscapes ranging from sandy coasts, over taxonomic problems within Oscinella may not be dry to humid grasslands to bogs, fens, marshes and fully elucidated on basis of morphology alone. other types of wetlands. Fewer chloropids are spe- The morphological terminology follows that pro- cialized forest inhabitants. The common name of posed in the Manual of Nearctic Diptera (McAlpine, these flies contains in many languages the word 1981). The treatment of each species begins with “frit”: frit flies, Fritfliegen, fritflugor, fritfluer. This the valid name followed by the original combina- word was used by C. Linnaeus, when he described tion followed by synonyms established after the the first species of the family as Musca frit (now Catalogue of Palearctic Diptera, vol. 10 (Soós & Papp known as Oscinella frit), a serious pest of cereals in many European countries. (eds), 1984) and listed chronologically with their The very first studies on chloropid flies came bibliographic references. Then follows a diagnosis from Swedish entomologists: C. Linnaeus (1707– and description to ensure correct differentiation 1778), C. Bjerkander (1735–1795), C.F. Fallén (1764– from related species. These are supplemented with 1830), J.W. Zetterstedt (1785–1874) and dealt with illustrations, mainly line drawings, of male geni- the local fauna. Their studies proved particularly talia and sometimes other body parts for nearly all important because they both contained descrip- the species. A few species cannot be safely identi- tions of new species and contributed information fied without examination of the male and female on the biology and damage to agricultural crops genitalia. Each description is followed by an out- caused by these flies. Many European and Palearc- line of the known distribution in Denmark and the tic species of Chloropidae were first described on Fennoscandian countries, and worldwide. Then basis of specimens originating from Sweden. Very follows a brief outline of bionomics in terms of phe- many chloropids in Europe have their northern- nology, habitat preferences and larval host plants. most distributional limit running through Sweden That piece of information, especially about host and the neighboring countries Norway and Fin- plants, is often based on extralimital observations land. in the absence of local data. Most frit flies, especially those belonging to the A Catalogue giving the known distribution by subfamily Chloropinae, have phytophagous larvae. faunistic province for each species in Denmark and In spite of their small size, their abundance gives Fennoscandia is provided in the format practiced them an important role in grass ecosystems as in previous volumes of the series. 2.