
38 R. COLLETT. [No 8-0 

The period passed by the swarms on the lowlands proper 
but seldom exceeds two years. If the advance guards of the 
emigrants begin to appear in the valleys during the autumn, 
the main advance will (in the great prolifit years) be made the 
following summer. Å few couples may then breed in the low- 
lands (probably only survivors from the previous year), and, 
shortly before the commencement of the autumn (the 2nd year), 
tha masses may be very considerable. In the course of the 
winter they decrease rapidly, and, when well into the following 
year, the second from the exodus, as a rule, but their dried up 
carcasses remain in the lowlands. 
In the northern parts of the land, the relations are some- 
what different. The lowlands in Finmarken are but slightly 
different in character to the mountain plateaux, and the lem- 
mings are thus enabled, and that in normal years, to inhabit 
in lesser numbers the lower tracts. During migratory years 
they may in countless numbers occupy all the valleys in those 
districts, down to the very edge of the sea. They may, how- 
ever, also settle down there and breed for several years after 
the migration. Wolley, in his previously mentioned lecture at 
Christiania in 18561, stated that, in the summer of 1855, in Fast 
Finmarken, he still found remnants of the migration that had 
taken place in those regions in 1952, as he discovered between 
20 and 30 individuals of various ages, on an islet about 50 paces 
in circumference, in the Varanger Fjord3. 
ania, and on both occasions they bred in the immediate vicinity 
of the town. 
The emigration of 1891 extended, so far as I am aware, not to 
the immediate environs of the city, but to the surrounding dis- 
tricts (Urskoug). 
2 Forh. Skand. Naturforskeres ”de Møde Christiania 1856, p. 218. 
8 It seems, however, to be more probable that the crowding of all 
these individuals into such a confined space, was due to a sub- > 
sequent immigration. 
