286 Insect and other Invertebrate Fauna 



abundant small insects, and the majority of the larvae, were white or 

 light-coloured. Other methods of obtaining the insects, etc., from the 

 soil were considered, but were not found to be feasible. By taking a 

 small quantity of soil at a time, and examining it in this way, it is 

 possible to obtain, probably, practically all the insects, etc., from the 

 soil, although it is likely that a few of the smaller forms would be over- 

 looked. 



Twenty-three cubes of soil, each 9" x 9" x 9", were examined in 

 this way, from each plot. They were taken alternately from the plots 

 about every six days, so that a cube was taken from each plot about 

 every 12 days. 



The time between successive cubes, however, varied somewhat 

 according to the weather and the condition of the soil. Cubes were not 

 usually taken on rainy days owing to the difficulties entailed in the 

 thorough examination of wet soil. 



Since this investigation was completed a method has been devised 

 by means of which the separation of insects and other arthropods from 

 the soil is much facilitated (ii). 



3. Soil Analyses. 



In order to define as exactly as possible the conditions under which 

 the soil fauna was existing on the two plots examined, mechanical and 

 chemical analyses of the soil of both plots were obtained. 



Plot 2. Percentages. Moisture (in air-dry soil) 2-22; Nitrogen 0-258; 

 Potash (soluble in HCl) 0-333; Phosphoric acid (soluble in HCl) 0-203; 

 Lime (as CaCOg) 3-43. 



Fine gravel 1-63; Coarse sand 2-57; Fine sand 21-96; Silt 17-30; Fine 

 silt I 11-66; Fine silt II 5-06; Clay 13-87; Loss on solution 7-38; Loss on 

 ignition 11-95. 



Plot 3. Percentages. Moisture (in air-dry soil) 1-7; Nitrogen 0-114; 

 Potash (soluble in HCl) 0-284; Phosphoric acid (soluble in HCl) 0-099; 

 Lime (as CaCOg) 4-01. 



Fine gravel 1-01; Coarse sand 3-17; Fine sand 23-31; Silt 20-36; Fine 

 silt I 6-22; Fine silt II 3-81; Clay 16-56; Loss on solution 6-88; Loss on 

 ignition 8-54. 



The figure for loss on ignition includes combined moisture as well as 

 organic matter. 



4. Meteorological Conditions. 



As the meteorological conditions probably exercise an influence on 

 the soil fauna, especially the rainfall and soil temperature, records of 



