Brachinus Bombardier beetles

Animals use chemical weapons for both defense and attack. Considering defensive tactics first, bombardier beetles (Brachinus spp.) can fire a hot solution of irritant... 

Survival techniques of insects and small animals in a fiercely competitive environment take many forms. For example, chameleons have developed the ability to change color to match their surroundings and the butterfly Limenifis has evolved into a form that mimics the poisonous and unpleasant-tasting monarch butterfly [Danaus], A less passive defense mechanism is employed by bombardier beetles [Brachinus], which repel predators with a "chemical spray."... 

Bombardier beetles. Beetles of the genus Brachinus and related species. They possess an abdominal defensive gland with which they can shoot explosion-like a hot secretion at an enemy. For this a 25% HjOj solution and a 10% solution of hydroquinone are injected into a combustion chamber . The catalases and polyphenol oxidases (temperature optimum of the enzymes 70-80 °C) present in the chamber effect an explosive reaction to water and benzoquinone or methyl-1,4-benzoquinone and the up to 70 °C hot mixture is shot speciflcally at the enemy. 

---