Osmia (Hemiosmia) difficilis Morawitz, 1875 Osmia difficilis Morawitz, 1875: 91. Type material: ♀, “in valle Sarafschan” (Tajikistan), Zoological Institute of Russian Acad- emy of Sciences St. Petersburg. Type species of Exosmia Tkalců. Osmia falcata Morawitz, 1875: 102. Type material: ♂, “in valle Sarafschan” (Tajikistan), Zoological Institute of Russian Acad- emy of Sciences St. Petersburg. Synonymy in Popov (1960). Osmia alborufa Alfken, 1935: 161. Type material: Holotype ♀, “bei Ankara in Anatolien und auf der Reise nach da” (Turkey), Senckenberg Frankfurt. Synonymy in Warncke (1988). Literature records. AZERBAIJAN: Nakhchivan (Kechili) (Proshchalykin et al. 2018). KAZAKHSTAN: Zhambyl (Aulie-Ata) (Zanden 1987). SYRIA: Al-Quneitra (Mt. Hermon) (Warncke 1988). TAJIKISTAN: Districts of Republican Subordination (Khodzha-Obi-Garm, Varzob, Ziddi), Sughd (Ansob) (Popov 1960). TURKEY: Ankara (Ankara, Elma Dag), Antalya (Saklikent), Balikesir (Erdek), Elazig (Elazig), Erzurum (Çat, Erzurum, Narman, Oltu, Serçeme), Hakkari (Oramar, Semdinli, Suvari-Halil pass, Tanin-Tanin pass, Varegös, Yüksekova), Kars (Sarikamis), Konya (Madensehir), Mersin (Sertavul), Sivas (Gürün), Tunceli (Tunceli), Van (Erçek) (Tkalců 1979; Zan- den 1987; Warncke 1988; Özbek & Zanden 1992; Özbek 2013). UZBEKISTAN: Qashqadaryo (Dukan-Khana), Samarqand (Aman-Kutan, Urgut) (Popov 1960; Tkalců 1979). New records. IRAN: Fars: Kharestan, 12.5.2011, 1♀, 14♂ (leg. R. Khodaparast, A. Monfared); Golestan: Shakuh-e Sofia, 36°32ʹ25ʺN / 54°26ʹ13ʺE, 2696 m, 1♀ (leg. W.H. Liebig); Isfahan: Semirom Abshar-e, 26.6.2009, 1♀ (leg. A. Monfared); Kohgiluyeh and Boyer-Ahmad: Yasuj region, Kakan, 30°36ʹ10ʺN / 51°47ʹ57ʺE, 29.5.2009, 1♀ (leg. C. Praz, C. Sedivy, A. Monfared); Theran: Firuzkuh county, Markazi district, Firuzkuh, 2200 m, 4.6.2005, 1♀, 2♂ (leg. Ø. Berg). KAZAKHSTAN: Zhambyl: Kara Tau, 1000 m, 3.6.1980, 1m (leg. Z. Padr). KYRGYZSTAN: Jalal-Abad: 10 km S Sari Tzelek, 42°N / 72°E, 5.6.1995, 2♀ (leg. J. Halada); Narin: Moldo-Too ridge, E Kara-Go pass, 41.30°N / 74.44°E, 2260 m, 30.6.1999, 1♀ (leg. J.G. Rozen). LEBANON: North: Bsharri, Dahr el Adib, 2407 m, 34°10ʹ58.3ʺN / 36°02ʹ09.2ʺE, 8.6.2017, 5♀, 7♂ (leg. M. Boustani). SYRIA: Al-Quneitra: Mt. Hermon, 2050 m, 31.5.1992, 1♀, 1♂ (leg. K. Warncke). TAJIKISTAN: Districts of Republican Subordination: 30 km NW Romit, 38°51ʹN / 69°00ʹE, 10.6.1975, 1♀ (leg. Y. Pesenko); Gorno-Badakhshan: 5 km E Khorog, 37.48136°N / 71.59382°E, 2114 m, 1.6.2009, 4♂ (leg. L. R. Best). TURKEY: Agri: Agri, 27.6.1993, 1♀, 1♂ (leg. J. Halada); Ankara: 10 km S Ankara, 1050 m, 21.6.1981, 1♀ (leg. K. Warncke); Antalya: 4 km E Saklikent, 36°52.51ʹN / 30°30.954ʹE, 1600 m, 30.5.2009, 1♀, 4♂ (leg. J.S. Ascher, J.G. Rozen, H. Özbek); Burdur: 20 km SW Burdur, 37°40ʹN / 30°28ʹE, 1350 m, 8.7.2006, 1♀ (leg. M. Kadlecová); Elazig: Elazig, 1300 m, 7.6.1980, 1♀ (leg. K. Warncke); Erzurum: Erzurum, Palandöken, 1.7.1996, 1♂ (leg. E. Yildirim); Hakkari: Tanin-Tanin pass, 1900 m, 3.6.1980, 1♂ (leg. K. Warncke); Izmir: 10 km NE Odemis, 38°20ʹN / 28°04ʹE, 1200 m, 3.7.2006, 1♀ (leg. M. Halada); Kars: Pasli, 50 km S Kars, 1.7.1997, 3♂ (leg. M. Halada); Kayseri: Avcipinari, 1510 m, 30°06ʹ06ʺN, 36°10ʹ04ʺE, 10.7.1995, 1♀ (leg. P. Ras- mont); Konya: Madensehir, 1300 m, 23.6.1984, 1♂ (leg. K. Warncke); Mersin: Kirobasi, 60 km E Mut, 19.6.1997, 1♀ (leg. M. Halada); Nevşehir: 20 km E Göreme, 9.5.1994, 1♂ (leg. K. Denes); Sivas: Gürün, 130 km S Sivas, 1600 m, 11.6.2001, 2♀, 5♂ (leg. K. Denes); Tunceli: Tunceli, 1850 m, 8.7.1975, 1♀ (leg. W.F. Reinig); Van: Muradje, 120 km NE Van, 2000 m, 5.6.2001, 1♂ (leg. K. Denes). UZBEKISTAN: Bukhara: Kyzyl-Kyr, 28.4.1978, 2♂ (leg. J. Strejcek); Qashqadaryo: Gissarsky Ridge, Koktugai pass, 38°27ʹN / 67°04ʹE, 29.5.1911, 1f (leg. A. Golbek); Surxondaryo: Baisuntau, Turap-Saj, S Sangarda, 31°31ʹ38ʺN / 67°30ʹ37ʺE, 1500–1700 m, 3.6.1997, 1♂ (leg. H. Rausch); Tashkent: Aktas, 70 km NE Tashkent, 41.2°N / 69.4°E, 27.5.1994, 1♀ (leg. M. Halada). Distribution. From Turkey eastwards over southern Azerbaijan and Iran to Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan) and southwards to the Lebanon and Hermon Mountains (Lebanon, Syria). The record from Russia listed by Müller (2019) and subsequently quoted by Proshchalykin & Fateryga (2017) is a mistake; it refers to a record from Aulie-Ata in the Kazakh Soviet Socialist Republic of the former Soviet Union (Zanden 1987). Pollen hosts. Oligolectic on Fabaceae (Tab. 1; Popov 1960; Özbek 1979, 2013; Özbek & Zanden 1992); pollen hosts are species of Galegeae (e.g. Astragalus), Genisteae, Hedysareae (e.g. Onobrychis), Loteae (e.g. Lotus), Trifolieae (e.g. Medicago, Trifolium) and other Fabaceae tribes. The larval provision of one brood cell from Iran exlusively consisted of pollen of Astragalus. Nesting biology. O. difficilis nests in excavated burrows in very loose, sandy to gravelly ground (C. Sedivy personal communication). The only nest discovered so far contained a single brood cell at the end of a 4 cm long burrow excavated in the wall of an irrigation ditch. The urn-shaped cell, which had a length of 15 mm and a maximal width of 8 mm, was entirely built of finely chewed leaves. Although consisting only of leaf pulp, the cell walls ranging in thickness from 0.3 mm to 1mm were surprisingly solid withstanding high physical pressure. In contrast to O. balearica and O. uncicornis, the cell was not attached to roots in the ground.

Published as part of Müller, Andreas, 2020, Palaearctic Osmia bees of the subgenera Hemiosmia, Tergosmia and Erythrosmia (Megachilidae, Osmiini): biology, taxonomy and key to species, pp. 201-236 in Zootaxa 4778 (2) on pages 213-214, DOI: 10.11646/zootaxa.4778.2.1, http://zenodo.org/record/3826170