140 INTERNAL ANATOMY OF INSECTS. 
however, that while in some constitutions the sting of a 
single bee or wasp is sufficient sometimes to induce 
alarming symptoms, in others numerous punctures will 
produce little or no pain or inflammation. ‘That this 
fluid, and not the puncture of the sting, is the sole cause 
of the inflammation that usually follows the wound in- 
flicted by one of these animals, is proved by the facts, 
that if it be introduced into one made by a needle, the 
same effect ensues, and that when the whole contents of 
the poison-bag have been exhausted by the insect’s sting- 
ing three or four times in succession, its weapon then 
becomes harmiess?. 
The venom of scorpions, though much more potent, 
probably resembles that of bees, &c., in many of its che- 
mical qualities: it issues from two pores in the sting be- 
fore described®, where, when the animal is irritated, it 
accumulates under the form of two little drops of a 
whitish colour; spread upon paper this fluid produces a 
spot like what would be caused by oil or grease, and this 
part of the paper becomes by desiccation firmer and 
transparent *. 
x. Odorous fluids and Vapours*. 'The powerful scents 
which different insects emit are extremely numerous, 
much more so indeed than the generality of Entomolo- 
gists have been aware, for there is scarcely a scent odious 
or agreeable that may not be met with in the insect 
world. This you will be convinced of, by following a 
practice which I would recommend to you — that of smell- 
, 
* Reaum. ubi supr. Vor. Tp: 1249p. F17—. 
© N. Dict. d’ Hist. Nat. xxx. 427. 
* I use the term odorous, not in the same sense as odoriferous, but 
to include both sweet and fetid scents. 
