86 BOOK OF NATURE LAID OPEN. 



have only two is amazing indeed. Flies, wasps, &c. 

 have the outward coat of their eye made of curious 

 lattice-work. Pagett is said to have discovered no 

 fewer than 17,325 lenses in the cornea of a butterfly ! 

 The eyes of insects are admirably adapted for see- 

 ing minute objects nigh at hand, but from the small- 

 ness and convexity of their lenses, it is apparent that 

 they can neither see far, nor take in the larger ob- 

 jects, and to remedy any inconvenience that might 

 arise from this, may have been the principal reason 

 why Nature has furnished them with those project- 

 ing horns or feelers with which they seem to grope 

 as they advance. Insects are also distinguished by 

 the number of their legs and wings; of the latter 

 most insects have four, while no other species of 

 animals have more than two; and although the 

 greater part have six legs, others, as Mites and Spi- 

 ders, have eight, and some ten, fourteen, sixteen, 

 and even a great many more. The palpi are those 

 little instruments fixed to the mouth of some insects, 

 which seem to be intended to serve the purpose of 

 arms, for they employ them to bring food to their 

 mouths, and to keep it steady when eating. Some 

 insects are furnished with stings for defence, or to 

 assist them in procuring their food, others with a tube 

 for injecting: their eggs into the most convenient si- 

 tuations for hatching. The females of some w inged 

 insects, for instance, insert their eggs under the sur- 

 face of leaves, and the worms w r hen hatched, give 

 rise to those tubercles or galls with which the leaves 

 of the ash, the fir, and other trees sometimes abound ; 



