416 MEANS OF DEFENCE OF INSECTS. 
horn! The “drowsy hum” of beetles, humble-bees, and other insects jn 
their flight, may tend to preserve them from some of their aérial assailants, 
And the angry chidings of the inhabitants of the hive, which are very dis- 
tinguishable from their ordinary sounds, may be regarded as, warning voices 
to those from whom they apprehend evil or an attack. I have before ob. 
served that the death’s-head hawk-moth (Acherontia Aéropos), when me. 
naced by the stings of ten thousand bees enraged at her depredations upon 
their property, possesses the secret to disarm them ‘of their fury. This 
insect, when in fear or danger, is known to produce a sharp, shrill, mourn- 
ful cry, which, with the superstitious, has added to the alarm produced by 
the symbol of death which signalises its thorax. This cry, there is reason 
to believe, affects and disarms the bees, so as to enable her to proceed in 
her spoliations with impunity.” One of these insects being once brought 
to a learned divine, who was also an entomologist, when he was unwell, he 
was so much moved by its plaintive noise, that, instead of devoting it to 
destruction, he gave the animal its life and liberty. I might say more upon 
this subject of defensive noises, but I shall reserye what I have further to 
communicate, to a letter which I purpose devoting to the sounds produced 
or emitted by insects. 
You are acquainted with the singular property of the skunk (Viverra pu- 
torius L.), which repels its assailants by the fetid vapour that it explodes ; 
but perhaps are not aware that the Creator has endowed many insects 
with the same property, and for the same purpose, some of which exhale 
powerful or disagreeable odours at all times, and from the general surface 
of their body; while they issue from others only through particular organs, 
and when they are attacked. 
Of the former description of defensive scents there are numerous ex- 
amples, in almost every order; for, next to plants and vegetable sub- 
stances, insects, of any part of the creation, afford the greatest diversity of 
odours, In the Coleoptera order a very common beetle, the whiriwig 
(Gyrinus natator), will infect your finger for a long time with a disagree- 
able rancid smell; while two other species, G. minutus and villosus, are 
scentless. Those unclean feeders, the carrion beetles ( Si/jpha L.), as might 
be expected from the nature of their food, are at the same time very fetid. 
Pliny tells us of a Blatta, which, from his description, is evidently the 
darkling-beetle (Blaps mortisaga), and which he recommends as an infallible 
nostrum, when applied with oil extracted from the cedar, in otherwise in- 
curable ulcers, that was an object of general disgust on account of its ill 
scent, a character which it still maintains *; which scent, from Mr. Thwaite’s 
investigation of the internal anatomy of this insect, proceeds from two 
small oblong vesicles near the anus, the fluid contents of which, when they 
are extracted and dissected under water, rise in a bubble to the surface, 
and there becoming vaporised diffuse the fetid smell peculiar to the 
species. Numbers of the ground-beetles (Eutrechina), that are found under 
1 Numerous other beetles make the same kind of sound, either by the friction of 
the head in the anterior prothoracic cavity, or by rubbing the narrowed front of the 
mesothorax against the sides of the posterior prothoracic cavity, or the abdomen 
against the elytra. 
? Huber appears to be of this opinion; he does not, however, lay great stress 
upon it. Yet there seems no other way of accounting for the impunity with which 
this animal commits its depredations, Huber, ii, 299, 
5 Hist. Nat. 1. xxix. c. 6. 
