Humble- Bees and other Matters. 155 



served them, there has occurred no change in their 

 relative positions; though both have greatly in- 

 creased in numbers during that time, owing to the 

 spread of cultivation. And yet it would scarcely 

 be too much to expect some marked change in a 

 period so long as that, even through the slow- 

 working agency of natural selection ; for it is not 

 as if there had been an exact balance of power be- 

 tween them. In the same period of time I have 

 seen several species, once common, almost or quite 

 disappear, while others, very low down as to 

 numbers, have been exalted to the first rank. In 

 insect life especially, these changes have been 

 numerous, rapid, and widespread. 



In the district where, as a boy, I chased and 

 caught tinamous, and also chased ostriches, but 

 failed to catch them, the continued presence of 

 our two humble-bees, sucking the same flowers 

 and making their nests in the same situations, has 

 remained a puzzle to my mind. 



The site of the nest is usually a slight depression 

 in the soil in the shelter of a cardoon bush. The 

 bees deepen the hollow by burrowing in the earth ; 

 and when the spring foliage sheltering it withers 

 up, they construct a dome-shaped covering of small 

 sticks, thorns, and leaves bitten into extremely 

 minute pieces. They sometimes take possession of 

 a small hole or cavity in the ground, and save 

 themselves the labour of excavation. 



Their architecture closely resembles that of B. 

 terrestris. They make rudely-shaped oval honey- 

 cells, varying from half an inch to an inch and a 

 half in length, the smaller ones being the first 



