Beetle that ejects audibly a pungent vapor when disturbed WordNet 3.0 & Open English WordNet

Bombardier beetles are ground beetles in the tribes Brachinini, Paussini, Ozaenini, or Metriini—more than 500 species altogether—which are most notable for the defense mechanism that gives them their name: when disturbed, they eject a hot noxious chemical spray from the tip of the abdomen with a popping sound. Wikipedia

Insect of family Carabidae Wikipedia Disambiguation

Beetles that emit a spray when threatened Wikidata

A beetle whose defence mechanism enables it to eject a hot aqueous mixture of chemicals at predators. They come from a number of subfamilies: Carabinae (e.g., Brachinus crepitans), Metriinae (e.g., Stenaptinus insignis) and Paussinae (e.g., Goniotropis nicaraguensis). Wiktionary

Beetle. Wiktionary (translation)