H6 INTERNAL ANATOMY OF INSECTS. 



markable, however, that while in some constitutions the 

 sting of a single bee or wasp is sufficient sometimes to 

 induce alarming symptoms, in others numerous punc- 

 tures 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 

 inflicted 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 harmless a . 



The venom of scorpions, though much more potent, 

 probably resembles that of bees, &c., in many of its 

 chemical qualities : it issues from two pores in the sting- 

 before 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 c . 



x. Odorous Jluids and Vapours*. The powerful scents 

 which different insects emit are extremely numerous, 

 much more so indeed than the generality of Entomo- 

 logists 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* 



a Reaum. ubi supr. b VOL. I. p. 124. III. p. 716. 



c N. Diet. d'Hist. Nat. xxx. 427. 



d I use the term odorous, not in the same sense as odoriferous, but 

 to include both sweet and fetid scents. 



