THE CONQUEST OF THE DRY LAND 197 



embryo-plant, the possible seed or ovule be- 

 comes a real seed, which will grow into a 

 plant when it is sown. So the more humble- 

 bees, the better next year's clover crop. 



But the nests of the humble-bees, which 

 are hidden in the ground or in a mossy bank," 

 are often burglared by the field-mice or voles, 

 which devour the white grubs of the bees. So 

 the more field-mice, the fewer humble-bees. 



But the cats on the prowl kill the field- 

 mice, which are therefore scarcer near vil- 

 lages than in the open country. The cats do 

 not appear to eat the field-mice, but they kill 

 them for sport. So the more cats, the fewer 

 field-mice. 



One may perhaps go a step further and say: 

 The more kindly ladies in the village, the 

 more cats there will be; and the more cats, 

 the fewer field-mice; and the fewer field- 

 mice, the more humble-bees; and the more 

 humble-bees, the better next year's clover crop. 



In any case, we must understand that the 

 pollination or fertilisation of flowers by their 

 insect-visitors, a linkage established after the 

 second great invasion, is one of the most 

 important linkages in the web of life. For 

 the fertilising dust or pollen is necessary if 



