Two New Species of the Genus Osmia from Japan and N. China (Hymenoptera, Megachilidae)

Abstract

This paper reports the results of two important findings which were made on the genus Osmia of Japan during last 23 years since Yasumatsu and Hirashima published the revisional work in 1950 (Mushi 21 (1) : 1-18, 3 ~1s.). As early as 1953, Dr. R. Ishikawa of the National Museum of Natural History, Tokyo, collected two females of a strange species belonging to the subgenus Melanosmia, which will be described as ishikawai sp. nov. in this paper, at fairly high altitude of Mt. Meakan, one of the famous mountains in Hokkaido. It was the discovery of the 6th species of Osmia of Japan. Unfortunately, no information of this species has been accumulated since the finding of it. Another discovery was made by Mr. K. Imai of the Hyogo Agricultural Experiment Station in 1972 in Himeji City, Hyogo Prefecture. He observed the species named as imaii sp. nov. in this paper was nesting in the trap nests of reed tubes set by himself. I was surprised to see the fact that such a distinct, formerly unknown species from Japan like this (unlike other Japanese species, hairs of the female bright red) was easily caught by trap nests in such a big city like Himeji. According to Mr. Imai’s investigation, the species is only found in Hyogo Prefecture so far, most common in the vicinity of Himeji City. It is very probable that the 7th species of Osmia of Japan is a recent immigrant from China. As stated below, the species is found also in Peking, N. China. This paper also reports the result of liberation of Osmia imaii in the Hakozaki campus of Kyushu University from the original stock gathered in Hyogo Prefecture. From the result a possibility is suggested of the management of this species for the pollinations of certain crops such as Brassica.