396 OIT INSECT ANATOMY. 



offence and defence; now thinning into diaphanous skin and 

 gossamer wing, bespangled with scales of exquisite beauty, whose 

 markings send microscopists into transports of enthusiasm (and 

 perplexity !) or covered with iiridescent hairs, spines, thorns, and 

 prickles of woful itching power, or emitting, to the dismay of the 

 collector, strange odours and irritant juices from glands beneath, or 

 again, armed with borers, grinders, pincers, saws, rasps, stings and 

 lancets worked with an intensity of power which, if exerted by an 

 animal of larger size and proportional muscular energy, would 

 appal a Titan — in short a dermo- skeleton which illustrates so com- 

 plete a repertory of mechanical contrivance, and enables the insect 

 to perform in miniature all that bird, beast, and reptile can do, is a 

 sufficient task for the most laborious student. 



But in addition to this external, we find an internal anatomy of 

 equal complicity, indicating in its highly specialised organs the 

 capacity of an insect to conform to every circumstance and influence 

 of its external surroundings. 



It is worthy of remark that the class Insecta is not a mere 

 connecting link in the chain of animal creation, but a kingdom 

 whose members inhabiting earth, air, and water, illustrate the 

 doctrine of adaptation under the most extreme conditions more 

 completely than any other class. And whilst repeating the 

 characteristics of other classes, and presenting various analogies 

 with animals both above and below them, possess, in addition, 

 individual and special characters of their own, and so special a 

 place amongst the great divisions of the Invertebrata as to stand 

 indisputably at their head. But, just as our ideas of life in its 

 most elementary form are best exemplified in the least organised 

 matter, so the most striking additions to, and extensions of this 

 elementary life might be expected to be seen in organisms, in which 

 the primary phenomena of living matter undergo the greatest 

 changes and transformations under the physiological rule of 

 adaptation to external influences. This is notably the case in 

 insects, and must be so when we consider the extreme as well as 

 middle ranges of insect life. And the result is seen not only in the 



