Hubert M. Morris 155 



2. In order to define the characters of the area under consideration 

 as clearly as possible, chemical, mechanical and botanical analyses were 

 carried out. 



3. Insects, largely in immature forms, were obtained by examining 

 samples of soil from various parts of the area, and in addition many 

 adults were obtained by sweeping the herbage with a net. The latter 

 method produced also some invading forms which did not belong to 

 the area. 



4. The factors influencing the distribution by depth of the insects 

 in the soil were in this case chiefly occurrence of food, aeration, and 

 moisture, and the result of these influences was that the insects seldom 

 penetrated even as deep as six inches, the vast majority of specimens 

 being found at a depth not greater than two inches. 



5. The census of insects actually found in the samples of soil gave 

 an insect population of 3,586,088 per acre. The family best represented 

 in number of individuals was the Bibionidae, species of which made up 

 32-4 per cent, of the total number of soil insects. The next in number 

 were the Mycetophilidae 16-7 per cent., and the Staphylinidae 12-2 per 

 cent. With regard to number of species occurring in the soil, the 

 Coleoptera, with 29 species, was the best represented order. 



14. References. 



1913. Cameron, A. E. General Survey of the Insect Fauna of the Soil. Journ. Econ. 



Biol. viii. 

 1917 Insect Association of a Local Environmental Complex in the district of 



Holmes Chapel, Cheshire. Trans. Roy. Soc. Edin. ill, Part I, No. 2. 

 1907 M'Atee, W. L. Census of Four Square Feet. Science, N.S. xxvr, pp. 447-449. 

 1903-14 Morley, C. British Ichneumons, i-v, London. 



