BIRDS AND INSECTS 175 



dark recesses of the soil. If we take a cubic foot of 

 the surface soil of a meadow and search it carefully, 

 bit by bit with a lens and a microscope, we find 

 hundreds of larvas and pupag and adults of insects that 

 feed upon the roots of the grasses or prey upon one 

 another, and many of these have not yet even been 

 named or described. Thus by this method Dr. 

 Cameron found in a small field near Manchester 160 

 different species of insects in the soil, many of them 

 being present in great numbers. 1 The play of forces 

 in this mixed community, the struggles for food, the 

 powers of reproduction, the death and destruction, is 

 intensely involved. All that we know at present is 

 that when we employ the method of injecting poisonous 

 vapour into the ground to destroy a particular species 

 of insect pest, we must also destroy hosts of other 

 insects, some of which at least are our friends and 

 benefactors. We are recklessly taking part in a war- 

 fare without knowing even the strength and disposition 

 of the forces that are fighting on our side. We are 

 striking out blindly, destroying friends and foes alike. 

 Now it seems to me that this state of things should 

 be amended. We should at least endeavour to extend 

 our knowledge of the natural forces that are playing 

 such an important part in the maintenance of the 

 fertility of our own soil. But this work which should 

 be done, which must be done if we are to have a really 

 scientific basis for our agriculture, requires the services 

 of properly trained entomologists. But of young 

 entomologists we have but a few left in this country ; 

 some of them are fighting in the ranks, others are 

 threatened with a summons to the colours, and others 

 have been driven abroad or into the service of the 

 colonies by the want of recognition at home. We 



1 A. E. Cameron: /. Econom. Biol,, VIII, 1913, and Trans. Roy. Soc., Edin- 

 burgh, LI I, 1917. 



