142 Elgee: The Driftless Area of North-East Yorkshire. 
Europe we find that its head-quarters are in France, and that 
the further north we go the rarer it becomes. Thus, in France 
there are thirty species, in Germany eleven, in Sweden two, and 
in Finland two. Russia has ten species (it is not stated whether 
all these are found in South Russia or not ; some occur in the 
neighbourhood of Elizabethgrad), Italy seven, and Greece three. 
Two species occur in Britain, JZ. europea and M. ephippium, 
both practically limited to the south-east of England. From 
these facts it seems clear that the Mutille have spread over 
Europe from the south, and this inference is further confirmed 
by the fact that in North Africa twenty-one species live in Algeria, 
two in Tunis, two in Tangiers, twenty in Egypt, etc. Moreover, 
six species are common to Europe and Africa. 
It is known from geological data that North Africa and the 
‘south of Spain were at one time connected by a land bridge, 
and across this 'and must have come the European Mutille. 
The genus is certainly not of European origin, as over 1000 
species are known from all parts of the world, chiefly the tropical 
parts of Africa, Australia, and South America. In the New 
World, the further north we go the rarer the genus becomes, as 
the following figures show :— 
South America 133 species. 
Central America 25 species. 
North America 15 species. 
The same decrease towards the north is shown here as in Europe. 
It must, therefore, be concluded that ages ago the Mutillz 
originated in tropical regions, whence they have spread over a 
greater part of the earth. Mutclla europea and its congener 
entered England when our island was part of the Continent, and 
probably formed part of the oldest fauna of Britain, and belonged 
to the Lusitanian invasion of Dr. Scharff. It would then 
gradually spread over the country in pre-glacial times; with the 
oncoming of the Ice Age it would be exterminated in the 
glaciated area, but would manage to survive in the south and 
on the driftless area. This region is quite suited to its habits, 
possessing a sandy surface soil such as the insect loves. Of 
course, the bees on which it is parasitic must have survived as 
well. Moreover, the very fact that the ant lives at the present 
day in Sweden and Finland proves that it can withstand a cold 
climate. In this way would the curious distribution of this 
insect in England appear to be accounted for, and if we 
accept the opinion of Dr. Scharff ‘that the climate of Europe 
Naturalist, 
