From the information we thus possess, we learn that some of our genera have an extremely wide diffusion, and occur in countries where we might have expected that other forms would have superseded them in the offices they are ordained to fulfil. None of the schemes for the geographical distribution of insects yet propounded, seem to curb the eccentricities of their range. The regions proposed by Fabricius in his ‘Philosophia Entomologica,’ they break through as readily as through the concentric circles of the cobweb when this opposes them: and all I can do is to present them as they offer themselves, with the remark that the occurrence of solitary forms in certain localities are almost sure indications that allied genera would be found at hand were they heedfully sought. It will also be observed, that in some places a parasitical genus, and its known sitos, only, have been captured there.
The following list will strongly show how totally our genera of bees are unaffected by isothermal, isotheral, or isocheimal lines drawn over the earth’s surface. Nor do botanical conditions seem to influence them beyond, the probability of their dissemination being restricted to the special diffusion of the families of such plants whose genera and species they frequent with us.
Thus, inhabiting Northern Europe we find in—
_Lapland._ Cilissa; Anthophora; Epeolus; Megachile; Chelostoma; Heriades; Osmia; Apathus; Bombus; Apis.
_Finland._ Colletes; Prosopis; Cilissa; Anthophora; Nomada; Epeolus; Stelis; Cœlioxys; Megachile; Anthidium; Chelostoma; Heriades; Osmia; Apathus; Bombus; Apis.
_Sweden._ All our genera except Sphecodes; Halictus; Macropis; Anthocopa.
_Denmark._ All our genera except Macropis and Anthocopa.
_Russia._ All our genera except Macropis and Anthocopa.
_The other Northern European Countries._ All our genera, with the same exceptions.
Western, Southern, and Eastern Europe present us with, in—
_Portugal._ Prosopis; Sphecodes; Andrena; Halictus; Eucera; Nomada; Anthidium; Apathus; Bombus; Apis.
_Spain._ Prosopis; Sphecodes; Andrena; Halictus; Dasypoda; Eucera; Anthophora; Nomada; Megachile; Anthidium; Apathus; Bombus; Apis.
_Italy._ Andrena; Halictus; Panurgus; Eucera; Anthophora; Nomada; Melecta; Epeolus; Cœlioxys; Megachile; Anthidium; Osmia; Apathus; Bombus; Apis.