Brachinus sp. (Bombardier Beetle).
 
 
 
Size: approx. 12 mm. Photo: 04/21/15, 10 pm.


Bombardier beetles have developed a chemical defense mechanism against predators. They can eject a foul-smelling, toxic gas from their abdomen. The gas is composed of hydrogen peroxide, hydroquinone, and catalytic enzymes. The ejection creates a loud popping sound. The larvae of the bombardier beetle are parasitoids of aquatic beetle pupae and scavenge body of host after its death  
 
 
bug guide (this photo):
http://bugguide.net/node/view/1058560
wikipedia:
http://en.wikipedia.org/wiki/Bombardier_beetle