Osmia (Hoplosmia) picena (Tkalcu, 1999) has a very restricted geographic distribution. To our present knowledge, it exclusively occurs in mountaineous areas of Central Italy. The species was known so far only in the female sex. On an excursion to the Abbruzzi mountains in August 2010, A. Müller discovered the unknown male.
The subgenus name Microhoplitis Tkalcu, 1993 is a junior homonym of the lepidopteran genus name Microhoplitis Marumo, 1920 (Kocak and Kemal, 2010). As there is no junior synonym of Microhoplitis Tkalcu, 1993, Kocak and Kemal propose Tkalcua as replacement name.
Based on the type specimens, Hoplitis (Annosmia) lefeberi Zanden, 1991 and Hoplitis (Annosmia) hierichonica wolfi (Warncke, 1991) are identical species. The former name is the junior synonym due to the date of publication.
In two samples of bees collected at the same locality and date in Turkey and Iran, respectively, females of Osmia (Pyrosmia) oramara Warncke, 1992 were found together with several males that exactly correspond to the description of the male of Osmia (Helicosmia) livida by Tkalcu (1978). As in both samples no females of O. livida were found, the male of O. livida as described by Tkalcu (1978) might be the still unknown male of O. oramara. If further material should support this assumption, then i) O. oramara would be a member of the subgenus Helicosmia rather than of the subgenus Pyrosmia, and ii) the male of O. livida would be still unknown.
Hoplitis (Pentadentosmia) laeviscutum (Alfken, 1933) is a junior synonym of Hoplitis (Pentadentosmia) rufopicta (Morawitz, 1875). Several males and females of Pentadentosmia from Central Asia, which were identified by V. B. Popov as Hoplitis rufopicta, were found to be morphologically identical with typical specimens of Hoplitis laeviscutum from Turkey and Israel (A. Müller, unpublished). The extent of the red colour of the cuticula appears to vary much intraspecifically: specimens from Turkey, Israel and Jordan are virtually devoid of red, while some specimens from Central Asia and Pakistan have their abdomen entirely red coloured. Even among individuals flying at the same locality, there are transitions from purely black specimens to specimens with differing amounts of red, as exemplified by a series of Hoplitis rufopicta recently collected by C. Praz, C. Sedivy and A. Monfared in Iran.
The species status of Osmia (Helicosmia) labialis Pérez, 1879 is disputed. Warncke (1986) synonymized it with Osmia melanogaster Spinola, 1808, while other authors considered it as a valid species different from O. melanogaster (Tkalcu, 1975c; Rasmont et al., 1995; Amiet et al., 2004). In a sample of bees from France, two specimens of Helicosmia were recently found that had been collected at the same day and exactly the same location. One of these specimens showed all characters typical of O. labialis as given by Tkalcu (1975c), the other specimen was a typical O. melanogaster. The syntopic occurrence indicates that O. labialis indeed warrants the status of a valid species.
Osmia (Melanosmia) hyperborea Tkalcu, 1983 is a junior synonym of Osmia (Melanosmia) laticeps Thomson, 1872 (Nilsson, 2009).
Wainia (Caposmia) guichardi (Zanden, 1991) was known so far only in the male sex. On an excursion to southern Morocco in April 2009, the unknown female was discovered (A. Müller, unpublished).
Hoplitis alexandrina (Warncke, 1991) is a junior synonym of Hoplitis hofferi (Tkalcu, 1977) based on types and the original description (A. Müller, unpublished).
Hoplitis acuticornis penelope (Warncke, 1991) is the so far unknown male of Hoplitis nigrocolor (Zanden, 1991) based on recently collected material in Tunisia (A. Müller, unpublished). Thus, it is newly treated as a synonym of H. nigrocolor. The synonymization of Hoplitis acuticornis penelope with Hoplitis camelina (Benoist, 1934) by Zanden (1996b) is erroneous.
Hoplitis brevifurca (Benoist, 1934) is the so far unknown male of Hoplitis sinuata (Pérez, 1895) based on recently collected material in Morocco (A. Müller, unpublished). Thus, H. brevifurca is a junior synonym of H. sinuata.
Osmia frunseensis Warncke, 1992 is junior synonym of Osmia carinoclypearis Wu, 1985 based on the original descriptions and recently collected material (A. Müller, unpublished).
Osmia atroalba Morawitz, 1875 is junior synonym of Osmia fasciata Latreille, 1811 based on type specimens and original description (A. Müller, unpublished).
Osmia prasina Morawitz, 1875 is a valid species based on type material and original description (A. Müller, unpublished); its synonymization with Osmia sogdiana Morawitz, 1875 by Warncke (1988a. 23) is erroneous.
Chelostoma palaeastinum (Benoist, 1935) is a junior synonym of Chelostoma schlettereri (Friese, 1899) based on comparison of type specimens (A. Müller, unpublished).
Chelostoma subnitidum (Benoist, 1935) is a junior synonym of Chelostoma ventrale Schletterer, 1889 based on comparison of type specimens (A. Müller, unpublished).
The genera Afroheriades, Pseudoheriades and Noteriades, formerly believed to belong to the Osmiini (Michener, 2007), do not appear to be members of this tribe (Praz et al., 2008b). Therefore, they are removed from the osmiine bees.