PARTS OF ANIMALS, IV. vi. 



themselves, being land-creatures and having a tail, 

 are bound to have their sting on their tail ; otherwise 

 it would be no use for exerting force. No two- 

 winged insect has a sting at the rear ; these are small 

 weak creatures, and can be supported by a smaller 

 number of wings : that is why they have only two. 

 The same reason explains why they have their sting 

 in the front : owing to their weakness they cannot 

 well deliver a blow with their hind parts. Many- 

 winged creatures, on the other hand, owe their 

 greater number of wings to their own greater size, 

 and so too their hind parts are stronger and bear the 

 sting. It is better, when it is possible, that one and the 

 same organ should not be put to dissimilar uses ; that 

 is, there should be an organ of defence which is very 

 sharp, and another organ to act as a tongue, which 

 should be spongy and able to draw up nourishment. 

 And thus, whenever it is possible to employ two 

 organs for two pieces of work without their getting in 

 each other's way. Nature provides and employs two." 

 Her habits are not those of the coppersmith who for 

 cheapness' sake makes you a spit-and-lampstand 

 combination. Still, where two are impossible, Nature 

 employs the same organ to perform several pieces 

 of work. 



Some insects, whose eyesight is not distinct owing 

 to their eyes being made of some hard substance, have 

 specially long forefeet, which enable them to clear 

 away anything that comes down on to the eyes. 

 Flies and bees and the like are obvious examples : 

 they are always crossing their front legs. These 

 creatures' hind legs are longer than their middle ones 

 for two reasons : (1) to assist them in walking, and 

 (2) to lift them more easily off the ground when they 



M , 3-i7 



