Introduction
With over 52000 species globally, nematocerans or lower Diptera are one of the most species-rich insect groups in the world (Pape et al. 2009). Within Nematocera, the most successful terrestrial group is the Bibionomorpha, including a majority of the saproxylic, fungivorous and herbivorous species (e.g. Mycetophilidae and Cecidomyiidae, Marshall 2012). As in many other biotic groups, Fennoscandian or North European bibionomorphans are perhaps the best known on the globe, especially regarding fungus gnats (or Sciaroidea, excluding Sciaridae). Despite the taxonomic and faunistic tradition starting from the 18th century (see Kjaerandsen et al. 2007b), species are continually added to the Nordic list (Søli and Rindal 2012, Jakovlev et al. 2014), including species new to science (e.g. Kjaerandsen et al. 2009, Salmela and Suuronen 2014, Kurina et al. 2015). No less than 915 fungus gnat species are currently known from the Nordic countries and Russian parts of Fennoscandia (Karelia and Murmansk oblast), consisting of approximately 83 % of the total European fungus gnat fauna (Kjaerandsen 2015). Nevertheless, at least 100 Fennoscandian fungus gnat species await formal naming and description (Kjaerandsen J., Polevoi A., Søli G., Salmela J., in prep.), raising the total number of species occurring in the area to around 1000. Non-herbivorous, or fungivorous and saproxylic gall midges (Cecidomyiidae) are far more poorly known than fungus gnats. In their recent monographs on the Nordic fauna, Mathias and Catrin Jaschhof (Jaschhof and Jaschhof 2009, Jaschhof and Jaschhof 2013) have described dozens of new species and have much advanced the faunistic knowledge on Lestremiinae and Porricondylinae. For example, the number of Finnish Cecidomyiidae have increased from 136 (Hackman 1980) to 356 (Jaschhof et al. 2014), mainly due to taxonomic and faunistic work performed during the last ten years. However, both Lestremiinae and Porricondylinae should still be considered as poorly known groups, and further additions to the Nordic and Finnish lists are expected.
A list of Finnish Diptera was recently published (Kahanpää and Salmela 2014). In the present paper, 12 species was added to this list (3 Cecidomyiidae, 1 Keroplatidae, 8 Mycetophilidae) and the occurrence of one keroplatid species that was erroneously deleted from the Finnish list was confirmed. Thus, the number of Finnish fungus gnats and gall midges now totals 772 and 359 species, respectively.
Materials and methods
All material reported here was collected from Finnish Lapland (Fig. 1). Lapland is an administrative area, covering a land area of ca. 100k km2. The SW corner of the area, close to the Baltic Sea, is middle boreal. The central part of Lapland is north boreal: coniferous forests prevail in the landscape, but there are isolated tree-less fells. Northernmost Lapland is an oroarctic area, sometimes called subalpine ecoregion. Fells and mountain birch forests prevail; isolated pine forests occur in some river valleys. The length of the thermal growing season (i.e. the number of days with the average temperature greater than + 5 C degrees after snow melt) is ca. 140-150 days in the middle boreal and ca. 105-110 days in the subalpine ecoregion (http://ilmatieteenlaitos.fi/terminen-kasvukausi, website accessed28.4.2015).
All material is deposited in the private collection of Jukka Salmela, Rovaniemi (JES). All specimens are stored in 70 % ethanol, kept in 2 ml plastic vials with screw cap and a rubber o-ring seal. Hypopygia of some specimens are kept in separate 0,5 ml microvials in glycerol.
Layer photos were taken using an Olympus E520 digital camera, attached to an Olympus SZX16 stereomicroscope. Digital photos were captured using the programmes Deep Focus 3.1 and Quick PHOTO CAMERA 2.3. Extended depth of focus images were reconstructed in the program Combine ZP.