The genus MEGACHILE, which embraces the most renowned of the mechanical bees, is extremely cosmopolitan, spreading north and south, east and west; and is also very abundant in the numbers of its species, the census extending to not far short of two hundred. Some one, or several of our species, although other species are limited to our own country,—spread through Italy and France, and all the countries of northern Europe to the high latitude of Lapland, which is higher than where even one of ours (viz. the _M. centuncularis_) is again found, which occurs in Canada and at Hudson’s Bay. The genus also frequents southern Europe, in Spain, Sicily, and Albania, and in the East, in the Caucasus and Dalmatia. It traverses Turkey by Bagdad to India, having been captured in Nepaul, and it descends southward in the Indian peninsula, where it has been found at Bombay. From India it stretches to the Mauritius, thence across the Indian Ocean to Java, and thence to Hongkong and northern China. It then dips to the Philippines, and doubtless through the islands of the Indian Archipelago to Australasia, from which continent none are registered from its northern and eastern settlements, but species abound along its southern edge from Western Australia, through Adelaide to Tasmania. The genus has been brought from the West India islands, St. Thomas’s, St. Croix, and Cuba: it is found upon the main from Mexico, descending to the Brazils. It skirts all the coasts of Africa, being discovered in Egypt and Algeria, along the western coast by the Gambia, Senegal and Sierra Leone to Guinea, and the island of Fernando Po, and then again occurs at the Cape of Good Hope. Ascending the eastern coast by Natal, it stretches to Abyssinia. The species are very abundant in India, Africa, and Australasia. The genus ANTHIDIUM, although very numerous in species, and differing more remarkably in form amongst themselves than most other genera, has a far less extensive range, no species having been found in Australasia or India, although it occurs in Arabia, Syria, and Mesopotamia. Our own solitary species occurs in France, Italy, and the whole of northern Europe, extending to Finland. In southern Europe the genus inhabits Sicily, Spain, the Morea, Albania, and Dalmatia, and is also very abundant in Southern Russia. In Africa it is found in Nubia and Algeria, and on its north-western edge in Barbary, whence it descends by the Gambia and Sierra Leone to the Cape of Good Hope, and thence reaches to Natal. It is then found in Chili, and crossing the South American continent occurs in the Brazils, whence it ascends to Cayenne, and, by way of Mexico, to the United States. The number of species recorded exceed a hundred.