The genus PROSOPIS, or as it is more familiarly known by the name of HYLÆUS, is found in some of our native species throughout France and Germany, and, like the preceding, as high up as Finland, through Denmark and Sweden, to the adjacent parts of Russia. It is remarkable that it is caught in Algeria, although not recorded as occurring in several of the southern European States. But the apparent restriction of some of our species to our own islands possibly arises from the fact of special attention having been paid to them in this country only. The genus itself, in other and more variegated forms than ours, presents itself in some portions of southern and south-western Europe, where the highly ornamented species would point almost to the certainty of its being a parasitical genus, great decoration being in our native genera of bees the badge of parasitism, and may be indicative of those habits, combined as they are conjunctively with their destitution of polliniferous organs. Some of our native entomologists have, however, assumed, upon what appears to me very inconclusive grounds, that the genus is not parasitical. The observations, however, of the most distinguished French hymenopterologists confirm the notion of their being parasites, which appears strengthened by the argument above suggested with regard to colour. This genus is apparently fond of hot climates. In eastern Europe, it occurs in Albania and the Morea, its extreme western domicile is Portugal, and its southern European habitat is Sicily. It is found in Algeria and Egypt, and at the Cape of Good Hope. We discover it in India, in the southern tropics at the Brazils, and in the northern tropics at the Sandwich Islands; and it ranges along the southern edge of Australia, from Swan River through Adelaide and Port Phillip to Tasmania. The United States of North America furnish it, and on that continent it seems to contradict its ordinary tropical inclination by being exceptionally found upon the confines of the arctic circle at Hudson’s Bay. Nearly sixty well-distinguished species are recorded. The genus SPHECODES has also a wide distribution. Our native species are found throughout France and Germany, Greece and Spain, still one or two seem limited to our islands. The genus is recorded as in Albania, Algeria, and Egypt; it is found on the western edge of Africa at the Canaries; it occurs also in northern India, in the United States, on the western side of South America at Chili, and then we have a wide gap, for its next appearance is at Sydney, New South Wales. About twenty species are known.