peritreme
/ˈpɛrɪtriːm/(also peritrema) Zoology
noun
A small chitinous ring or tube surrounding a spiracle or breathing hole in some insects and arachnids, especially acari.
Origin
Mid 19th century; earliest use found in Richard Owen (1804–1892), comparative anatomist and palaeontologist. From peri- + ancient Greek τρηματ-, τρῆμα perforation, hole.