Bombardier beetles are ground beetles (Carabidae) 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.
Bombardier beetle
Australian bombardier beetle (Pheropsophus verticalis)
Benzoquinone
Ground beetles are a large, cosmopolitan family of beetles, the Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. As of 2015, it is one of the 10 most species-rich animal families. They belong to the Adephaga. Members of the family are primarily carnivorous, but some members are herbivorous or omnivorous.
Ground beetle
A crucifix ground beetle (Panagaeus cruxmajor) got Charles Darwin into trouble in 1828.
A Brachinus species typical bombardier beetle (Brachininae: Brachinini) from North Carolina
A Lophyra sp. tiger beetle from Tanzania