156 NATURE'S TEACHINGS. 



It was, however, nothing but a trap, for it had no exit. AB 

 soon as a number of the assailants had poured into this trap, 

 their exit was suddenly cut off by machinery provided for the 

 purpose, and at the same time a quantity of sulphur and lighted 

 charcoal was shot into the gallery from above, and the aperture 

 instantly closed. It would be absolutely impossible that any 

 one who had been enclosed in that terrible chamber should 

 escape with life, for the first breath of that deadly vapour would 

 render the strongest man insensible. 



NATURE, as usual, has anticipated Art even in this par- 

 ticular. 



In several parts of England, and especially along the shores 

 of the Thames towards Gravesend, a little beetle is to be found 

 under the flat stones of the river bank. Its scientific name is 

 Brachinm crepitans. When this insect is alarmed, it has the 

 power of ejecting a peculiar liquid, which, when it comes in 

 contact with the atmosphere, bursts into a sort of pale blue- 

 green flame, followed by a kind of smoke. Sometimes, when a 

 tolerably large stone is lifted, the little explosions will go 

 popping about in a most curious manner. Indeed, they carry 

 reminiscences of school days, when it was a joy to distribute 

 single grains of coarse gunpowder on the bars of the grate, 

 and watch them melt, take fire, explode, and send forth little 

 clouds of smoke. 



Whether or not this capability was given as a means of 

 defence I cannot say, but it assuredly answers that purpose. 



There are several of the voracious Carabidae, or Ground- 

 beetles, which would be very glad to make a meal of the 

 Brachinus. When, however, the Bombadier-beetle finds itself 

 on the point of being overtaken, it elevates the abdomen with 

 a peculiar gesture, and ejects the liquid. The effect on the 

 pursuer is remarkable. It seems overwhelmed and stupefied 

 by the sudden attack, moves about for awhile as if blinded, 

 and, by the time that it has recovered its sense, the Bombadier- 

 beetle is out of sight. 



In some of the hotter parts of the world there are several 

 species of Bombadier-beetles which attain considerable size, 

 and their discharge is powerful enough to discolour the skin of 

 the human hand. 



