( lxiv ) 
of birds,’* are too minute to be adopted for butterflies, and I 
should be disposed at present only to admit the following :— 
Ist. The Boreal, which would prebably include his first four 
subregions, namely the Arctic, Alaskan, Aleutian, and Cold 
Temperate. Though we know almost nothing of the 2nd and 
3rd, we cannot expect many Lepidoptera to exist there ; and 
the other two, including the higher elevations of the Rocky 
Mountains and of California, are inseparable from the Boreal 
region of Hurope and Asia, and coincide with the Polar and 
British N. Anferican floras of Hooker. 
2nd. Sharpe’s Humid Province, which he divides into the 
Appalachian and Austro-riparian subprovinces, and which 
coincides with the Great Eastern Forest Reyion of Hooker, 
of which the Southern, especially a part of the Littoral area, 
is so largely tinged with a West Indian element, both in plants 
and butterflies, but not apparently in birds, that it forms a 
transition area to the Antilles. 
8rd. Sharpe’s Arid Province, which includes his Campestrian 
and Sonoran sub-Provinces, and the southern part of the 
Prairie Region of Hooker, together with the great deserts of 
Utah, New Mexico, Arizona, and Western Texas, which is 
characterized by the comparative scarcity of most of the domi- 
nant northern genera, and shows a Mexican and Neotropical 
element by the presence of many Hesperiida, a few Evycinida, 
and other genera not found to the north, and for the most 
part represented by a few species with Mexican affinities. 
This forms a transition area to the Mexican Province of the 
Neotropical region, and being almost entirely a region of great 
aridity, and without forest, forms, in the same way as the 
African Sahara does, a barrier to the northern extension of all 
the Neotropical species which inhabit forests. 
I have mentioned these divisions in greater detail, because 
it is clear, from the remarks of Dr. Dixey in a recent paper in 
our Transactions (Trans. Ent. Soc., 1894, p. 822), that there is 
* Natural Science, Vol. III., Aug., 1893. 
+ The Distribution of the North American Flora. A lecture delivered on 
April 12, 1878, before the Royal Institution cf Great Britain. ‘ Gardeners’ 
Chronicle,’ Aug., 1878. 
