1917] The Ottawa Naturalist. 107 



emerge again. An examination revealed the spider in a torpid con- 

 dition with a large cylindrical shaped white egg attached to the under 

 side of its abdomen. This spider was placed in a glass vial and on the 

 8th had fully recovered its activities. It ate flies readily thereafter 

 and was kept alive until July 15, when being unable to longer resist 

 the sapping of its vitality by the large larva, which the Pompilus egg 

 had produced, it died. This Pompilus larva had in seven days 

 attained a truly remarkable size and was almost 20 mm. long at the 

 time of the spider's death. It only survived its host, however, for a 

 short time, so that the further stages of its life could not be ascertained. 

 This is but a single example of the many tragedies that occur in, or 

 around, the spiders' homes Wasps of many kinds roam these sand 

 dunes in large numbers and there is no doubt that spiders form quite a 

 large percentage of their prey. That the spiders in their turn, have 

 found it a profitable hunting ground is equally demonstrated by the 

 large number present in the neighbourhood. 



A XOTE OX THE MIGRATION OF THE BARREN 

 GROUND CARIBOU. 



By E. M. Kindle. 



There is perhaps no more curious and interesting phenomenon 

 connected with the wild life of Northwestern Canada than the semi- 

 annual migration of the Caribou, Rangifer arcticus. The vast herds 

 of these deer, which summer in the barren lands far to the east of the 

 Mackenzie river, move southward in the late autumn from the treeless 

 barrens of the Arctic slope and seek the shelter of the forested region 

 east of the Slave and Athabasca rivers. The writer traversed both of 

 these rivers and a part of the Mackenzie river during the past summer 

 but neither saw nor heard of any caribou having been observed during 

 the summer. With the coming of winter, however, they appeared east of 

 the Slave river in vast numbers, as the following letter from Inspector 

 K. F. Anderson of the R. N. W. Mounted Police clearly indicates. 



R. N. W. M. Police, 



Fort Fitzgerald, 



December 15, 1917. 

 E. M. Kindle, Esq., 

 Ottawa. 

 My dear Mr. Kindle : 



There is nothing new here except the Caribou. They are 

 within forty-five miles of this place in tens of thousands and the 

 natives are getting numbers of the animals and will therefore 

 have plenty to eat this winter. The Deer (Caribou) are passing 



