246 MEANS OF DEFENCE OF INSECTS. 
its receptacle, till the pressure is repeated, when it re- 
appears ?. 
I shall now introduce you to the true counterparts of 
the skunk, which explode a most fetid vapour from the 
ordinary passage. I have lately hinted that the scent of 
many Carabide is thus emitted. Harpalus prasinus, a 
beetle of this tribe, combats its enemies with repeated 
discharges of smoke and noise: but the most famous for 
their exploits in this way are those, which on this ac- 
count are distinguished by the name of bombardiers 
(Brachinus, ¥.). The most common species (B. crepi- 
tans, F.), which is found occasionally in many parts of 
Britain, when pursued by its great enemy, Calosoma In- 
quisitor, F., seems at first to have no mode of escape ; 
when suddenly a loud explosion is heard, and a blue 
smoke, attended by a very disagreeable scent, is seen to 
proceed from its anus, which immediately stops the pro- 
gress of its assailant: when it has recovered from the 
effect of it, and the pursuit is renewed, a second dis- 
charge again arrests its course. The bombardier can 
fire its artillery twenty times in succession if necessary, 
and so gain time to effect its escape-—Another species 
(Brachinus Displosor,) makes explosions similar to those 
of B. crepitans : when irritated it can give ten or twelve 
good discharges; but afterwards, instead of smoke it 
emits a yellow or brown fluid. By bending the joints of 
its abdomen it can direct its smoke to any particular 
point. M. Leon Dufour observes that this smoke has 
a strong and pungent odour, which has a striking ana- 
logy with that exhaled by the Nitric Acid. It is caustic, 
* De Geer, v. 291, Compare Ray’s Letters, 43. See Pratr XVIII. 
Fic. I. 
