Checklist of the ‘lower Brachycera’ of Finland: Tabanomorpha, Asilomorpha and associated families (Diptera)

Abstract A checklist of the ‘lower Brachycera’ of Finland is presented. This part of the complete checklist of Finnish Diptera covers the families Acroceridae, Asilidae, Athericidae, Bombyliidae, Mythicomyiidae, Rhagionidae, Scenopinidae, Stratiomyidae, Tabanidae, Therevidae, Xylomyidae and Xylophagidae.


Introduction
This part of the checklist of the Diptera of Finland covers non-eremoneuran true flies (Diptera: Brachycera). The brachyceran flies excluded from the clade Eremoneura are often called the 'lower Brachycera' due to their basal position in the true fly tree of life. It remains unclear whether this assemblage of families is a monophyletic clade. There are also several models for the relative relationships of the various superfamilies and families. A simple classification scheme following Marshall (2012) is adopted for this checklist. Only two infraorders, Tabanomorpha and Asilomorpha, are recognized. The presentation order of families follows .

Tabanomorpha
The stratiomyoid and xylophagoid lineages are often treated as infraorders ).
The soldierflies (Stratiomyidae) are very diverse in the tropics but the species diversity decreases sharply towards the higher latitudes. The wood soldier flies (xylomyids) is a small fly family associated with dead wood. The Fauna Entomologica Scandinavica series has a volume on stratiomyoid flies (Rozkošný 1973). A new Nemotelus species was recently described from Finland (Kahanpää 2010a).
The Finnish rhagionids are relatively well known but a few additional species could occur in the country. Ptiolina is a problematic genus and the number of recognized species in Northern Europe has varied from two to seven during the last century. Athericidae was traditionally placed as a subfamily of Rhagionidae, but it seems more closely associated with Tabanidae (Marshall 2012). Itämies et al. (1990Itämies et al. ( , 1993 have studied the distribution of Atherix ibis in Finland. The Finnish xylophagid fauna is relatively well sampled. Adults of the North European species can be identified using Nartshuk (1988) or Kahanpää (2009). The larvae can also be identified at least at the last larval stage (Stubbs andDrake 2001, Krivosheina andKrivosheina 1966).
The tabanid nomenclature (especially Hybomitra) is quite convoluted and records in older publications must be taken with a grain of salt. Karvonen (1969) summarized the distribution of tabanids in Finland, but this work is now partially obsolete due to the difficulties in identifying Hybomitra and Haematopota before Chvála et al. (1972) was published. For identification of North European tabanids Chvála et al. (1972) complemented with pictures in Zeegers and van Haaren (2000) or Krčmar et al. (2011) is recommended. An illustrated guide to the Finnish species is in preparation (A. Haarto, unpublished).

Asilomorpha
The asilids and bombyliids of Finland are rather well known from a faunistic point of view but little is known about their ecology. Most of the North European species are easy to identify but problems with Villa resulted in a cascade of name changes in the late 20th century. Falck (2009) andBlöchlinger (2008) are good starting points for identifying Villa adults. François (1969) has male genitalia figures for some of the more difficult Villa species. The Mythicomyiidae or micro bee flies were long seen as a subfamily of Bombyliidae.
Identifying Thereva species was also fraught with difficulties in the past but by the end of the 20th century the North European fauna was pretty well understood. A review of the Finnish therevid fauna with keys has recently been published (Haarto and Winqvist 2006). The window flies, Scenopinidae, is a smallish asiloid lineage associated with the therevids. It has even been proposed they are a specialized subgroup of the Therevidae ).

Acroceridae
The small-headed flies (Acroceridae) are a fly family of obscure origin. Affinities with Nemestrinidae, Tabanoidea, Stratiomyoidea, Bombyliidae and Asilomorpha have been proposed (see Marshall 2012 for further discussion). Finnish acrocerid records are mostly of single adults caught by sweep-netting, although Storå (1956) found groups of 20-40 Acrocera orbiculus swarming on a coastal meadow. The acrocerid species seem to have declined in abundance during the 20th century. Four of our five Finnish species are now on the national red list (Kahanpää 2010b).  (Szilády, 1932) Xylophagus kowarzi (Pleske, 1925)

Notes
Choerades ursulus (Loew, 1851) is a poorly known taxon. It was synonymized with C. fuliginosus by Lehr (1991) but later considered valid by Bosák and Hradský (2001). Kahanpää and Winqvist (2005) accepted it as a Finnish species but upon re-examination we consider it most likely that the single Finnish specimen previously identified as C. ursulus is a dark male of C. fuliginosus. Chrysopilus suomianus (Szilády, 1934). The type locality of this species is Enontekiö, Finland (Szilády 1934). Unfortunately the type material seems lost and the name is probably best treated as a nomen dubium. Based on Szilády's original description it may be a dark form of C. nubecula. Hybomitra astuta (Osten Sacken, 1876). Kahanpää and Winqvist (2005) could not locate any material in Finnish collections. Several new records of this species have since been made and its presence in Finland is now confirmed .  Hybomitra auripila (Meigen, 1820). The synonymy of Hybomitra auripila (Meigen, 1820) with H. aterrima (Meigen, 1820) was established by Schacht (1994) and is accepted here. Schiner (1862) Vuorimies (1984). Unfortunately the specimens listed in his paper could not be found and their identification remains somewhat doubtful.

Ogcodes borealis Cole, 1919.
A single Finnish specimen collected in the mid-19 th century is the sole Palearctic record of this species. Originally identified and published by Hackman (1970), the record was later confirmed by Kahanpää and Winqvist (2005). O. borealis Cole sensu Schlinger (1960) may be a species complex. Ogcodes nigripes (Zetterstedt, 1838) is probably a senior synonym of O. zonatus Erichson, 1840. Ptiolina nigrina Wahlgren, 1854 may be a synonym of P. nigra Zetterstedt, 1842. Scenopinus sp. A is an apparently undescribed species near S. fenestralis with black femora. It occurs widely in Finland in association with bird nests. Villa halteralis (Kowarz, 1883). See Kahanpää and Winqvist (2005) for a discussion of the single supposed Finnish record of this species. Xylophagus ater Meigen, 1804. This name has widely been used for two species. Old Finnish checklists (Frey et al. 1941, Hackman 1980 followed the model also used in the world checklist Woodley (2011c) and used this name for the species also known as Xylophagus kowarzi (Pleske, 1925). On the British Isles the name X. ater is used as a senior name for X. compeditus Wiedemann in Meigen, 1820. According to Alexander and Clements (1991) and Chandler (1998a, b) the British usage is correct and it is followed here. Thus, X. ater is the common species with females easily identified by the three stripes of dusting on the mesonotum.  (Krivosheina and Krivosheina 2000). It was raised to a full species status in the recent world catalogue (Woodley 2011c). All collected Finnish specimens formerly identified as X. matsumurae were examined and they belong to X. inermis. Zabrachia tenella (Jaennicke, 1866). First recorded from Finland by Krivosheina and Rozkošný (1990). We have examined the Finnish Zabrachia material and confirmed the presence of both Z. tenella and Z. minutissima in the country.