The remarkable genus CHELOSTOMA is very limited in the numbers of its species, of which less than a dozen are known; as also in the extent of their distribution. Our own are found throughout northern Europe, as far as Lapland, and in Russia. In southern Europe they occur in the Morea, and the genus has been discovered in Georgia in North America. The closely-allied genus HERIADES seems limited to a European habitation, and occurs only in our own solitary species, but it ranges, like the preceding, to the high latitudes of Lapland. ANTHOCOPA seems limited to our own country and France, possibly only from its having been associated from similarity of general habit with the genus _Osmia_. Only one species appears to be known, but this has a world-wide celebrity, from the interesting account given by Réaumur, of its hanging its abode with symmetrical cuttings from the petals of the poppy. The genus OSMIA, although not including such able artisans as _Megachile_, still has in its species very constructive propensities. Indeed, all the bees which convey the pollen on the under side of the abdomen, are more or less builders or upholsterers. The genus has a wide range, and is tolerably numerous, numbering more than fifty species. Some of our own occur throughout Europe, and, like the two preceding genera, are found in the highest continental latitudes. Some of ours also occur in Algeria and the Canaries, other species in Albania and Moravia. In Africa they are found in Egypt, Barbary, and Port Natal, and in the New World from Florida, in the United States, through Nova Scotia to Hudson’s Bay.