BRN 9-2 (uncompressed) - Flipbook - Page 39
The two protrusions at the very end (right side) of the
caterpillar in the top photograph are the anal prolegs. The
locomotion of a caterpillar is ÒhydraulicÓ, involving the
pumping of blood from one part of the body to another. The
legs are used for grasping and holding as one part of the
body is ßooded with blood, causing the other to contract
(legs grasp), blood ßows back, repeating sequence.
The three pair of legs at the front of the caterpillar are called
thoracic legs. They are jointed and have hooks which are
used in grasping food.
Note bottom photo, above, shows the variability in length of
the setae. This is also shown in the center left photograph
on the following page.
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