1963] 
Matthews — Behavior of Canthon 
8 3 
ascertain the probability that the distributions obtained might have 
resulted by chance. Four class intervals were used for this, correspond- 
ing to four directions rather than the eight shown in the diagrams, 
since the numbers are too small to give meaningful results for eight 
class intervals. The chi-square figures and corresponding probabilities 
for three degrees of freedom are indicated in each diagram. 
The diagrams and numbers may be interpreted as follows: If 
the distribution is significantly skewed when all observations are 
plotted in relation to the direction of one particular factor, we may 
expect that this factor overrides all others in governing the direction 
the ball is rolled. Such a factor is obviously the slope of the ground, 
the beetles rolling uphill (P=<.oo5) (fig. 8). Another strong 
factor appears to be the wind direction (balls rolled with the wind), 
but it is evidently not as overriding (P=.025 — .05) (fig. 6). When 
all observations are plotted in relation to the position of the sun, the 
resulting diagram is not very strongly skewed, having a relatively high 
probability of being a chance distribution (P=.o5 — .10) (fig. 9). 
We may interpret this to mean that the sun position is the least influ- 
ential of the three factors analyzed. 
In order to pinpoint more accurately the influence of a single 
factor it is better to subtract observations which were also under the 
influence of other factors. It was possible to plot the directions in 
relation to the wind where the ground was level (minus the ground 
slope factor) (fig. 7), but this did not reveal a more significant 
relationship, for some reason. To have subtracted the sun factor 
as well would have left too few observations. 
The situation with regard to the sun is quite different when we 
plot the observations obtained when the other factors played no part, 
that is, when there was no wind and the ground was quite flat. In 
these cases, the distribution is very significantly skewed, with 13 out 
of the 19 observations being either directly toward or directly away 
from the sun (fig. 10). The probability that this could have been 
brought about by chance is .005. It appears, therefore, that the sun 
is used in some way in guidance, providing more important factors 
do not intervene. More will be said on this matter in the discussion 
at the end of the paper. 
The relation to the wind may be simply explained : the beetle 
approaches the dung from down-wind and therefore tends to work 
on the leeward side of the dropping. Once made, the ball is simply 
rolled away from the dropping, and this will automatically be more 
or less in the direction of the wind, other factors being equal. The 
