please identify this bug
March 15, 2010
I found this in my jacket! I don’t want to kill it if it is harmless or useful.
Charlotte, North Carolina
This is a False Bombardier Beetle in the genus Galerita. According to BugGuide, the False Bombardier Beetles can be distinguished from the true Bombardier Beetles by the “Large size, blue/black striated elytra, brown pronotum, legs, palpi. Head black, unlike the bombardiers, Brachinus, which have a brown head, and are usually smaller (4-15 mm).” False Bombardier Beetles are beneficial predators with a unique defense mechanism. According to the Proceedings of the National Academy of Sciences (PNAS) of the United States of America website: “The carabid beetle Galerita lecontei has a pair of abdominal defensive glands that secrete a mixture of formic acid, acetic acid, and lipophilic components (long-chain hydrocarbons and esters). Formic acid, at the concentration of 80%, is the principal constituent. The beetle ejects the secretion as a spray, which it aims accurately toward parts of the body subjected to assault. At full capacity, the glands store 4.5 mg of formic acid (3% of body mass), enough for upward of six ejections.”