CH. VIII.] COLEOPTEROUS INSECTS. ' 141 



interval it takes tlie opportunity of escaping. In 

 this way the artillerymen can keep up a running 

 fire, so as to let off twenty good discharges suc- 

 cessively. On lifting up a large stone in gravelly 

 situations, an explosion will be heard, and a streak 

 of smoke occasionally seen issuing from the ground ; 

 — no sooner is the alarm thus given, than twenty or 

 thirty other subterranean volcanoes vomit forth 

 their little smoke, evidencing the terror and the 

 remedy for it of a colony of Bombardier beetles. 

 There is also another species, rather smaller than 

 the former, which is capable of exploding in the 

 same manner about ten or twelve good discharges ; 

 but they afterward emit a yollow or brown fluid. 

 The smell of the smoke is strong and pungent, and 

 has some similarity with that exhaled by nitric acid ; 

 the fluid is caustic, and turns paper red, and pro- 

 duces on the skin, when handled, the sensation of 

 burning and forming red spots, which pass into a 

 brown colour, and, though washed, remain several 

 days. One insect of this tribe is said, in addition 

 to the mere explosion, to have the power of guiding 

 with its hind limbs the acrid smoke to any given 

 spot, so as literally to entitle it to the credit of 

 being a decent shot. 



