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Caterpillar Up Close
A follow iamge of the Black Swallowtail, this specimen's much bigger. If you look closely at the caterpillars side, you can see the oval shaped external openings (spiracles) of the tracheal system that allows for respiration.. The caterpillar contracts muscles to open and close the spiracles. One spiracle pair is on the first thoracic segment; the other 8 pairs are on the first lower 8 abdominal segments..

A follow iamge of the Black Swallowtail, this specimen's much bigger. If you look closely at the caterpillars side, you can see the oval shaped external openings (spiracles) of the tracheal system that allows for respiration.. The caterpillar contracts muscles to open and close the spiracles. One spiracle pair is on the first thoracic segment; the other 8 pairs are on the first lower 8 abdominal segments..

Copyright Howard B. Cheek