Taenidia (singular: taenidium) are circumferential thickenings of the cuticle inside a

trachea The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from ...

or tracheole in an

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

's respiratory system. The geometry of the Taenidiae varies across different orders of insects and even throughout the tracheae in an individual organism. Taenidia generally take the form of either hoop or spiral thickenings of the tracheal cuticle.

References

* Mill, P.J., ''Tracheae and Tracheoles'' Microscopic Anatomy of Invertebrates, 11A, pp. 303–336, 1998. Insect anatomy {{insect-anatomy-stub