326 PTILOTA : PHYSIOLOGY AND 



daceous water-beetles also, by similar emissions, but more 

 particularly by their capability of flight in the air, swimming 

 in the water, or creeping on the land, are enabled to avoid 

 the attacks of enemies which might assault them in any 

 of these elements. We have seen that many beetles, as 

 the pill-beetles [Byrrhidce), the death-watches {Anobiuin), 

 and the mimic - beetles (Hlsteridce), with many others, 

 possess in a remarkable degree the power of counter- 

 feiting death, by folding up their limbs and keeping them 

 in a state of inactivity. Other beetles, by the similarity 

 of their appearance to the sand or earth in which they 

 reside, readily elude our observation, as in many sand 

 heteromera. The emission of similar foetid scents and fluids 

 by many other beetles, as the SilpJddcB, Ckrysomelida, and 

 especially the lady-birds, is a very ordinary means of de- 

 fence ; whilst the similarity in the colourmg of others to the 

 leaves, stems, or bark of plants and trees, is equally service- 

 able. The threatening aspect of some, as the devil's coach 

 horse ; the rapidity of the m.ovements of others, as the Hal- 

 ticcB, joined to their minuteness, all tend to the same end. 

 The larvae of the Cassidce and Crioceridce cover themselves 

 with a cloak formed of their own excrements, which serves as 

 a protection against the sun, and conceals them from their 

 enemies. 



In the Orthoptera we find great locomotive powers, as ex- 

 hibited by the locusts and grasshoppers, whose strength in 

 leaping is known to every schoolboy ; but there are other in- 

 sects belonging to the same order equally well defended, al- 

 though their locomotive powers are but slight. Here we are 

 to notice the walking-leaf insects and the walking-stick 

 insects, objects which to an ordinary observer would appear 

 but detached leaves or tmgs rustling with every breath of air; 

 but they have life, and Nature has given them their strange 

 appearance with a view to its preservation, by deceiving 

 those animals which might otherwise make them their prey. 



