thyridium

== English == === Etymology === From Latin thyridium, from Ancient Greek θυρίδιον (thurídion), diminutive of θύρᾱ (thúrā, “door”). === Noun === thyridium (plural thyridia) (entomology) A spot in the wing veins of Neuroptera, Hymenoptera and Trichoptera. (entomology) A spot on both sides of the second abdominal tergite in ichneumonids