Data on the distribution of Dolichopodidae (Diptera: Empidoidea) in Bulgaria, with first records for the country

The paper presents information about 37 dolichopodid species, collected from 14 localities in Bulgaria. Five species (Medetera murina, Systenus scholtzi, Neurigona nubifera, Rhaphium antennatum and Sciapus bellus) are recorded for the first time for the fauna of Bulgaria. The species S. scholtzi is new to the Balkan Peninsula and the genus Systenus is a new genus of the family Dolichopodidae for the Bulgarian fauna.


Introduction
The family Dolichopodidae encompasses small-to middle-sized species (1 to 10 mm). The flies of the family, also called long-legged flies, are predators and among their food sources are small invertebrates as ticks, insects (imago and larvae), worms and etc. The adults dwell in humid habitats around rivers, ponds, marshes, lakes and sea shores and rocks, and are also found in deciduous and coniferous forests. Their body is most often metallic-green but in some species could be yellow or blue. About 8 000 different species are described worldwide, excluding Antarctica. In Bulgaria, 204 species are known up to now (Kechev et al., 2020;Kechev & Glogov, 2021;Kechev, 2021).
The main purpose of this paper is to provide new records of the family Dolichopodidae for Bulgaria and data on the distribution of the dolichopodids in poorlystudied areas in the country.

Material and methods
The material for the present work was collected from 12 localities in Bulgaria ( Fig. 1) using Malaise traps, two types of emergency traps (tree and soil traps) and sweep nets. The species were separated in the laborat-ory using a Carl Zeiss microscope. For the determination of dolichopodids were used publications by Parent (1938), Stackelberg (1969), d'Assis Fonseca (1978), Grichanov (2007) and Negrobov & Naglis (2016). The species new to Bulgaria are marked with one asterisk (*) and the new one for the Balkan Peninsula with two asterisks (**) in front of the names. The material presented in this paper is housed in Mihail Kechev's    Sciapus flavicinctus (Loew, 1857) -Material examined: site 13a: 1 ♂; site 13b: 1 ♂, 2 ♀♀; site 13c: 1 ♀; site 14a: 1 ♂.

Discussion
Sciapus bellus, Neurigona nubifera, Rhaphium antennatum, Medetera murina and Systenus scholtzi are re-corded for the first time from Bulgaria. With these results the number of dolichopodids known for the Bulgarian fauna is increasing to 209 species. Systenus scholtzi is also new for the Balkan Peninsula. Systenus is presented with seven European species. Until now, two species have been known for the Balkan Peninsula; they were listed from Croatia: Kechev & Ivanova (2015a), Pollet & Ivković (2018) and Drake (2018) listed Systenus bipartitus (Loew, 1850), while Naglis (2017) described Systenus bartaki from Gornji Muć Village, near Split.
Three of the species listed in this paper (Neurigona nubifera, Sciapus bellus and S. platypterus) have been collected with a large number of specimens along riversides (sites 13 and 14, Figs 8 and 9). The single male specimen of S. bellus, mentioned above from the Vitosha Mt, has also been found along the riverside. Other reports of S. platypterus in Bulgaria are also mainly from river banks. This research suggests higher riparian affinity of these three species.
Poecilobothrus regalis is one of the most common species in the lower parts of Bulgaria, from sea level up to about 300 m. It is reported mainly from southern Bulgaria, where it has been found with large numbers of specimens on river banks, ponds and marshes (Kechev & Ivanova, 2015b, Kechev, 2019. Our study lists two new localities in northern Bulgaria.
Some regions in Bulgaria, including the Eastern Rhodope Mts, Pirin Mts, Rila Mts, Struma River Valley, are still not well studied in terms of their dolichopodid fauna. The southern parts of the E Rhodopes and the Struma River Valley are under the Mediterranean climatic influence. Future studies of these areas could results in the discovering of new species for the country and information on habitat preferences, and other ecological data for the family Dolichopodidae.