54 
DR ALFRED E. CAMERON. 
species as the author found early this year (1915) hibernating in the larval galleries 
of Rhagium bifasciatum in a felled tree at Whaley Bridge, Cheshire. 
Soil-Insect Census. 
The interest of an analysis of the insect numbers and species of definitely 
measured samples of soil first appealed to the author after perusing the data 
collected by various workers in their investigations upon the food of birds. In any 
given locality, a study of the relative abundance of the insect species and of the 
various birds which prey upon them, would be productive of much important 
information. Hitherto, most insectivorous birds have been classified as “ useful,” 
but one must discriminate between those which feed on pests and those which feed 
on insects that are themselves predaceous and therefore beneficial. It is extremely 
doubtful if a bird distinguishes between different insect species so far as to select one 
more than others as its prey. The fact that one species may predominate in a bird’s 
diet, as shown in post-mortem dissection, merely demonstrates that at a given time 
the particular insect was either very abundant or the most accessible in the district 
from which the bird was taken. Necessarily, to be complete, the insects which 
belong to each of the vertical strata of an association should be considered. But for 
such birds as starlings, rooks, and lapwings, which are typically ground-feeders, only 
the surface and subterranean insect strata need be dealt with. 
At the outset of the survey, whilst tentative efforts were being made to grasp 
the associational aspects of the insect complex, the very great abundance of Tipulid 
larvae in the Alluvial Pasture and their practical non-existence in Glover’s Meadow 
seemed to require explanation. In the case of wireworms, the facts were almost 
exactly reversed. Therefore, in order to ascertain whether there were similar or 
parallel phenomena with regard to other species due to the same or allied causes, the 
analysis assumed the form of a comparison between definitely measured samples of 
the two grasslands. It must be remembered that they differed principally as 
regards altitude and exposure, water-content of their soils, which were respectively 
alluvial and clay loams, and also in the texture of their soils, a fact which naturally 
depends on their different origins. In its ultimate composition, the flora did not 
differ greatly in the two. One field, however, the Alluvial, was grazed by cattle 
whilst Glover’s was left undisturbed. As these points have already been dealt with 
in detail, this brief restatement will be quite sufficient here. 
The method of procedure consisted in cutting out samples of soil of one cubic foot 
capacity. After the adhering plant-species had been determined, and, in a general 
way, their relative abundance, each sample was thoroughly and systematically 
investigated in the laboratory. As far as possible all insects, whether in the egg, 
larval, pupal, or adult condition, were enumerated. Tables X and XI represent 
briefly the results which this research produced. All insect specimens, whether they 
lived in the ground or merely inhabited the surface, are included in the two tables. 
