200 
COLOUR IN NATURE 
CHAP. 
take caterpillars, dragon-flies, bees, or other cases 
where the segmentation of the body is obvious, we 
find that, just as in leeches, the coloration bears a close 
relation to the segments, as is seen in the banding of 
many caterpillars, of the abdomen of dragon-flies, and 
so on. But since the Arthropods, as compared with 
worms, show a subordination of the individuality of 
the segments to the needs of the whole—a synthesis 
of segments—so we find that there is a constant 
tendency for the pattern to dominate the whole 
organism instead of being the result of the patterns 
of the segments. The whole is symmetrical round a 
median line, but is in most cases not merely due to 
the repetition of the patterns of the segments. This 
is especially well seen in caterpillars in the colouring 
of, for example, the head. This is a specialised 
region of the body often with much thickened cuticle, 
and accordingly we find that it often differs in 
coloration from the rest of the body. When we 
pass from caterpillars to forms like dragon-flies or 
bees, we find that, while the relation of the pattern 
to the segments is obvious in the relatively un¬ 
specialised abdomen, it is lost in the much modified 
thorax. In other bees again, as in some of the 
humble bees, the coloration has largely lost, even in 
the abdominal region, any direct relation to the 
segmentation. In this connection the coloration of 
spiders offers some points of great interest. As we 
have already seen, the markings, especially on the 
abdominal region, are often exceedingly complex. 
According to M'Cook, the markings tend to adopt a 
leaf-like shape, and these folia appear to be related 
to the little pits on the surface of the abdomen which 
