MEANS OF DEFENCE OF INSECTS. 229 



by giving it extraordinary powers of sustaining heat. 

 Other insects are as remarkable for bearing any degree 

 of cold. Some gnats that De Geer observed, survived 

 after the water in which they were was frozen into a mass 

 of ice: and Reaumur relates many similar instances 11 . 



The last passive means of defence that I mentioned, 

 was the multiplication of insects. Some species, the 

 Aphides for instance, and the Grasshoppers and Lo- 

 custs, have such an infinite host of enemies, that were it 

 not for their numbers the race would soon be annihi- 

 lated. But as passive means of defence have detained 

 us sufficiently long, it is enough to have touched upon 

 this head. Let us then now proceed to such as may be 

 called active ; in which the volition of the animal bears 

 some part. 



II. The active means of defence, which tend to se- 

 cure insects from injury or attack, are much more nu- 

 merous and diversified than the passive ; and also more 

 interesting, since they depend, more or less, upon the 

 efforts and industry of these creatures themselves. When 

 urged by danger, they endeavour to repel it either by 

 having recourse to certain attitudes or motions ; produ- 

 cing particular noises ; emitting disagreeable scents or 

 fluids; employing their limbs; or weapons, and valour; 

 concealing themselves in various ways ; or by counter- 

 acting the designs and attack of their enemies by contri- 

 vances that require ingenuity and skill. 



The attitudes which insects assume for this purpose 

 are various. Some are purely imitative, as in many in- 

 stances detailed above. I possess a diminutive rove- 

 a De Geer, vi. 35.5; comp. 320, and Reaum. ii, 141-147, 



