130 
Psyche 
[December 
classification of the mounds as to size 1 , and distribution on 
the margin, open, or in a clearing. The accompanying 
figure, showing a typical portion of the map on which all 
the mounds are located, clearly illustrates this sort of dis- 
tribution. 
Margin Open Clearing Total 
Small 1 54 56 33 143 
Medium 74 11 48 133 
Large 84 7 68 159 
Total 212 74 149 435 
Per cent 48.7% 17.% 34.3% 100.% 
Relation of Mound Distribution to Certain Environmental 
Factors 
In addition to mapping and classifying the mounds of 
this particular region, some attention was directed towards 
the status of the local environmental factors in order to 
detect any correlation between the particular conditions 
and the distribution of these nests. Inspection shows a 
relation between the nest distribution and light since all 
colonies are situated to receive direct sunlight for the 
greater part of the day. Also, the mounds themselves are 
so constructed that the maximal surface area is exposed 
to the sun rays while the perpetually shaded north side of 
the mound becomes, in many instances, a steep slope from 
the apex of the nest to the ground. This suggestion of light 
as a factor is further substantiated by the fact that 
wherever nests appear within the forest, rather than along 
the margins, they are located within an actual clearing, 
which permits practically the same amount of light to fall 
upon the mounds as does on the marginally located nests 
and those of the open territory. Using the Macbeth Illumi- 
nometer, the intensity of the light was measured in foot- 
candles, to ascertain if the margins and clearings, where 
mounds are found, are actually receiving more light than 
the shaded forest floor. This is summarized in the second 
table. 
1 Small mounds are those 6 inches to 1 1-2 feet in diameter; medium 
mounds, 1 1-2 to 3 feet in diameter; large mounds, 3 to 5 feet in 
diameter. 
