52 THE REPORT OF THE Xo. 36 



other small mammals. Some of the species of bumble-bee^ select a nest situated 

 in thick grass. Others, and these comprise the larger num!)er, prefer to live under- 

 ground with a long and winding tunnel leading to tlie nest. Occasionally a bird's 

 nest in a hollow tree is chosen, and a nest Ijetween the double walls of an out- 

 building meets the taste of some species. I once found a nest in an old shoe and 

 another in a rusty kettle lying on a rubbish lieap o^ergrown with weeds. 



The queen teases the material in the centre of the nest with her legs and this 

 makes it very soft and dry. Then she crawls into the middle of it and tramps it 

 down, forming a warm and cozy cavity. Here she accumulates a lump of pollen 

 about the size of a pea, and on this lump she lays her first batch of eggs which 

 number about a dozen. The eggs are laid in a little cell of wax which is con- 

 structed on the top of the pollen, and after they have lieen laid the cell is sealed 

 over with Avax. 



The process of poUen collecting is very interesting. The pollen dust gathers 

 in the long body hairs with which all bumble-bees are densely clothed, and it is 

 brushed out of these by the middle legs and conveyed to the mouth where it is 

 jnoistened with honey. The moistened pollen is then transferred to a particular 

 spot on the bristly inner side of one of the joints of the hind leg called the meta- 

 tarsus or planta. This is really the first joint of the foot. The next joint above 

 the metatarsus, namely the tibia, is provided at the end on the inner side with a 

 comb which is used to scrape the moistened pollen ofE the metatarsus of the oppo- 

 site leg into a receptacle at the end of the tibia. When the leg is straightened a 

 projection on the base of the metatarsus enters the receptacle and pushes the 

 pollen out of it on to the outer side of the tibia. As the result of many such con- 

 tributions the well-known pellet of pollen is formed on the outer side of the tibia, 

 and it is held in by a wall of stiff hairs surrounding it and acting like the stakes that 

 farmer places around his wagon when he desires to carry hay. Two or three stitf 

 hairs stand in the entrance to the pollen basket. The object of these seems to be 

 to form a means of attachment for the pollen before a sufficient quantity has accu- 

 mulated to be held by hairs at the sides. 



In the honey-bee the pollen collecting apparatus on the hind legs is essenti- 

 ally the same, but it is more specialized. The moistened pollen is spread over the 

 whole of the inner side of the metatarsus, the l)ristles tliere being arranged 

 in ten transverse rows, and they hold the pollen in greater quantity, while the 

 comb on the end of the tibia used for scraping it out of them is a very efficient 

 instrument. Its efficiency is enhanced by the fact there are no spurs on the end 

 of the tibia in the honey-bee, though these are present in the bumble-bee and all 

 tlie solitary bees and are useful to these in performing their toilet. 



It was formerly believed that a bee hardly ever visited more than one species 

 of flower on the same journey, but careful observers have foujid that under cer- 

 tain conditions changing from one species to another is not rare, and this has 

 been proved by the presence of variegated loads of ]-)ollen. Bumble-bees are more 

 inclined to change from one species of flower to another than honey-bees. This is 

 especially true in the case of the common European species Bomhus ierrestris, 

 which is cJosely related to the Canadian species B. ierricola. In a nest of B. ier- 

 restris that I kept under observation in July this year, 40 per cent, of the workers 

 returned home with variegated loads. In order to discover exactly how the pollen 

 basket is loaded I took sections of a number of the variegated loads collected by 

 the workers in this nest. In one of the most interesting of these, no less than 

 eight successive kinds of pollen were distinguishable. ■ The sections showed clearly 



