CHAP. XV.] 
THE NEARCTIC REGION. 
137 
together with many northern birds common to both conti- 
nents. Yet a few Palaearctic forms, not known in other parts 
of the sub-region, appear here. These are Budytes flava, Phyl- 
loscojpus kennicottii, and Pyrrhula coccinea, all belonging to 
genera not occurring elsewhere in North America. Considering 
the proximity of the district to North-east Asia, and the high 
probability that there was an actual land connection at, and 
south of, Behring’s Straits, in late Tertiary times, it is somewhat 
remarkable that the admixture of Palaearctic and Nearctic groups 
is not greater than it is. The Palaearctic element, however, forms 
so small a portion of the whole fauna, that it may be satisfactorily 
accounted for by the establishment of immigrants since the 
Glacial period. The great interest felt by ornithologists in the 
discovery of the three genera above-named, with a wren allied to 
a European species, is an indication that the faunas even of the 
northern parts of the Nearctic and Palaearctic regions are, as 
regards birds, radically distinct. It may be mentioned that the 
birds of the Aleutian Isles are also, so far as known, almost 
wholly Nearctic. The number of land-birds known from Alaska 
is 77 ; and from the Aleutian Isles 16 species, all of which, 
except one, are North American. 
Reptiles. — These are comparatively few and unimportant. 
There are however five snakes and three tortoises which are 
limited to Canada proper; while further north there are only 
Amphibia, represented by frogs and toads, and a salamander of 
the genus Plethodon. 
Fishes . — Most of the groups of fresh-water fish of the Nearctic 
region are represented here, especially those of the perch, 
salmon, and pike families ; but there seem to be few or no peculiar 
genera. 
Insects. — These are far less numerous than in the more 
temperate districts, but are still tolerably abundant. In Canada 
there are 53 species of butterflies, viz., Papilionidae, 4 ; Pieridse, 
2 ; Nymphalidse, 21 ; Satyridae, 3 ; Lycaenidae 16, and Hesperidae 
7. Most of these are, no doubt, found chiefly in the southern 
parts of Canada, That Coleoptera are pretty numerous is 
shown, by more than 800 species having been collected on the 
