MEANS OF DEFENCE OF INSECTS. _ 419 
smoke, attended by a very disagreeable scent, is seen to proceed from its 
anus, which immediately stops the progress 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; and 
what is still more remarkable, Mr. Holme found that by pressing the abdo- 
men near the anus, the discharges may be produced after death. In this 
way two specimens which had been dead eighteen hours gave, one fifteen, 
and the other nineteen discharges before being exhausted, and he even 
obtained explosions from some specimens which had been dead four days ; 
but most of these, along with the noise, discharged a black grainy fluid 
without smoke. Another species (2B. displosor) makes explosions similar 
to those of B. crepitans: when irritated it can give ten or twelve good dis- 
charges; 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 parti- 
cular point. M. Leon Dufour observes that this smoke has a strong and 
pungent odour, which has a striking analogy with that exhaled by nitric 
acid. It is caustic, reddening white paper, and preter on the skin the 
sensation of burning, and forming red spots, which pass into brown, and 
though washed remain several days.? This burning sensation, M. Lacor- 
daire informs us, when arising from the discharges of the large exotic 
species, is so painful, that he has often been obliged to let those which he 
had taken escape. The same power of emitting explosions, asa means of 
defence, is found also in some other coleopterous species, as in those of 
the genus Paussus, according to M. Payen, who had an opportunity of 
studying their habits in the isles of Sunda and the Moluccas ® ; in those of 
Cerapterus according to Mr. MacLeay‘; and in those of Ozena in a slight 
degree, according to M, Lacordaire. 
Another expedient to which insects have recourse, to rid themselves cf 
their enemies, is the erhission of disagreeable fluids. These, some discharg : 
from the mouth ; others from the anus; others again from the joints of 
the limbs and segments of the body ; and a few from appropriate organs. 
You have doubtless often observed a black beetle crossing pathways 
with a slow pace, which feeds upon the different species of bedstraw 
(Galium), called by some the bloody-nose beetle (Z'imarcha tenebricosa). 
This insect, when taken, usually ejects from its mouth a clear drop or two 
of red fluid, which will stain paper of an orange colour. The carrion- 
beetles (Sijpha and Necrophorus), as also the larger Carabi, defile us, if 
handled roughly, with brown fetid saliva. Mr, Sheppard having taken one 
of the latter (C. violaceus), applied it in joke to his son’s face, and was 
surprised to hear him immediately cry out as if hurt : repeating the ex- 
periment with another of his boys, he complained of its making him 
smart : upon this he touched himself with it, and it caused as much pain 
as if, after shaving, he had rubbed his face with spirits of wine. This he 
observed was not invariably the case with this beetle, its saliva at other 
times being harmless. Hence he conjectures that its caustic nature, in the 
instance here recorded, might avise from its food ; which he had reason to 
1 Trans. Ent. Soc. Lond. ii. proc. vii. 
2 Ann. du Mus. xviii. 70. % Lacordaire, Zntrod, a ’ Entom, ii. 56. 
4 Westwood, Mod, Classif. of Ins. i, 151. 
EE? 
