Notes on Xylocopa caffra (a Linné, 1767) (Hymenoptera: Apidae) and its parasitoid Coelopencyrtus sp. (Hymenoptera: Chalcidoidea: Encyrtidae) in the Republic of Seychelles, with an annotated catalogue of the genus Coelopencyrtus Timberlake, 1919 of the Ethiopian region