
40 R. COLLETT. [No. 3. 

had, however, bred there, and I found small younglings during 
August in the neighbourhood of Drammen. It was also reported 
from Tvedestrand that many pregnant individuals were each 
morning found lying in the streets. 
On the other hand the swarms became more and more 
numerous in Christiansand Stift, and throughout the entire 
autumn of 1863, they swarmed in all the coastal districts down 
to the sea shore itself. | 
Great swarms were already seen during the winter of 1862 
—63 pushing on from the westward across the river Lougen 
and the northern portions of the lake Mjösen, and occupying 
the eastern sides of the valley or the lake. It has not been af- 
firmed with certainty, whether they really spread from those 
places to the adjoining mountains; but first in 1863, they had 
their prolific year in the mountains of Gudbrandsdal (thus those 
chiefly belonging to the radiating centre No. 2), where in 1862, 
their increase had been but little above normal (least on the 
east side). 
With this, the migration, on the whole, ceased for these 
years. The last individuals died in the southern lowlands during 
the winter of 1863—64, and in the summer of 1864, most of 
the mountains were deserted, as well as the Gudbrandsdal moun- 
tains where, the previous year, they had been present in thou- 
sands. In the dJotunfjeldene a large tribe still remained and 
passed the summer of 1865. 
In the course of two years they had thus occupied all the 
southern and western lowlands to about as far as the river 
Glommen and the east side of the lake Mjösen, and the Ohristi- 
ania Fjord. 
During the years 1868—69 aå migration of very consider- 
able proportions took place from the 3rd district, or the moun- 
tains in the Trondhjem Stift. The hordes evidently had their 
starting point in the mountains along the Swedish frontier, 
whence they spread both westward as well as eastward, as they, 
in great swarms, oceupied the lowlands in Trondhjem Stift, at 
