MEANS OF DEFENCE OF INSECTS. 



it is impossible to hold your head near the nest of the 

 hill-ant (Formica rtifa), when the ants are much dis- 

 turbed, without being almost suffocated. This odour 

 thus proceeding from myriads of ants, is powerful enough, 

 it is said, to kill a frog, and is probably the means of 

 securing the nest from the attack of many enemies. 

 Dr. Arnold observed a species of bug (Scutettera) abun- 

 dant 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 

 emitted 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 inflam- 

 mation. In the evening, however, they appeared to sub- 

 side; 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 

 (Meloe Proscu.rabaeus\ and I dare say, when you took 

 it, have observed orange-coloured or deep-yellow drops 

 appear at its joints. As these insects feed upon 

 acrid plants, the species of crowfoot or Ranunculus^ it is 

 probable that this fluid partakes of the nature of their 

 food and is very acrimonious and thus may put to flight 

 its insect assailants or the birds, from neither of which 

 it could otherwise escape, being a very slow and sluggish 

 and at the same time very conspicuous animal. Another 

 beetle (Ellenophorus collaris) has likewise this faculty. 

 The lady-bird, we know, has been recommended as a 

 cure for the tooth-ache. This idea may have taken its 



