The Dipterans (Insecta: Diptera) of the Stara Planina Mountains, Bulgaria

A total of 1723 species of 70 families have been established in the Stara Planina Mts. so far. The family Mycetophilidae is the most numerous (219 species or 12.7%), followed by Tachinidae (161 species or 9.3%), Muscidae (157 species or 9.1%) and Agromyzidae (101 species or 5.9%). The greatest number of species have been found in the Western Stara Planina Mts. (1087 species or 63.1%), in the belt of the mesophilic and xeromesophilic mixed forests (1432 species or 83.1%) and north of the central ridge (1289 species or 74.8%). The faunistic similarity between the separate parts of the mountain is scrutinised. The dipterans belong to 121 areographical categories, divided into two main groups: 1) species with Mediterranean distribution (103 species – 6.0%): more thermophilic and distributed mainly in the southern parts of the Palaearctic and the lower parts of the mountains; 2) species with Palaearctic and Eurosiberian distribution (1620 species – 94.0%): more eurybiontic and widely distributed in the Palaearctic and in the mountains. The Holomediterranean and South-eastern European forms (from 0.5% to 0.7%) are the best represented in the first group. The European, Holarctic and Transpalaearctic taxa (from 6.4% to 18.1%) prevail in the second group. The endemic species are 24 (1.4%). The distribution of the areographical categories in the separate parts of the mountain and the vegetation belts is also scrutinised.