250 MEANS OF DEFENCE OF INSECTS. 



lar means. The fluid in this had a powerful odour of 

 musk. — The acid of ants has long been celebrated, and 

 is one of their most powerful means of defence. When 

 the species that have no sting make a wound with their 

 jaws, they insinuate into it some of this acid, which 

 Fontana affirms is the acid of fixed concentrated air 

 deprived of its elasticity and rendered liquid^. The 

 efBuvia produced by this acid are so subtile and pene- 

 trating, that it is impossible to hold your head near the 

 nest of the hill-ant (Formica rufa^ L,)? when the ants 

 are much disturbed, without being almost suffocated. 

 This odour thus proceeding from myriads of ants, is 

 powerful enough, it is said, to kill a frog, and is pro- 

 bably the means of securing the nest from the attack 

 of many enemies. — Dr. Arnold observed a species of 

 bug (Scutellera, F.) abundant upon some polygamous 

 plant which he could not determine, and in all their 

 different states. They were attended closely by hosts 

 of ants, and when disturbed ensitted a very strong 

 smell. One of these insects ejected a minute drop of 

 fluid into one of his eyes, which occasioned for some 

 hours considerable pain and inflammation. In liie 

 evening, however, they appeared to subside ; — but on 

 the following morning the inflammation was renewed, 

 became worse than ever, and lasted for three days. 



Other insects, when under alarm, discharge a fluid 

 from the joints and segments of their body. You have 

 often seen what has been called the unctuous or oil 

 beetle (3Ieloe Proscarabcezis, L.), and I dare say, v/hen 

 you took it, have observed orange-coloured or deep-? 

 yellow drops appear at its joints. As these insects fee4 



" On Poisons, i. 269— 



