Microscopical Essays. 



Motion is one of the principal phenomena of nature* and as it 

 were the foul of our fyftem ; and is as admirable in the fmalleft 

 animal as in the univerfe at large. It may not be amifs juft to 

 notice here, that there are fome infects of the beetle kind, which 

 contradict an aflertion of Borelli's, that an animal puts in action 

 each foot on one fide before it moves thofe on the oppofite fide ; 

 whereas thefe employ in walking the two moll diftant feet on the 

 fame fide, and the middle foot on the oppofite ; a method which 

 is firm and natural. 



The wings, thofe organs by which the infect is enabled to 

 fly ; fome have only two/ others are furnifhed with four, two on 

 each fide ; thefe are in fome of the fame fize, in. others the fu- 

 perior ones are much larger than the inferior. The variety in the 

 form and ftructure of the wings is almoft infinite j the beauty of 

 their colouring, the ait with which they are connected, to, the. 

 body, the curious manner in which fome are folded up, the fine - 

 articulations provided for this purpofe, by which they are laid 

 up in their cafes when out of ufe, and yet ready to be extended 

 in a moment for flight ; together with the various ramifications, 

 by which the nourifhing juices' are circulated, and the wing 

 firengthened, afford a fund of rational investigation highly en- 

 tertaining, exhibiting, particularly when examined by the micro- 

 fcope, a molt wonderful difplay of divine wifdom and power. 

 The more delicate and tranfparent wings are covered and pro- 

 tected by elytra, or cafes, which are generally hard and opake, 

 often highly polifhed, adorned with ornamental flutings, and 

 fludded with brilliants. The wings of moths and butterflies are 

 moftly farinaceous, covered with a fine duft, that oecafions thofe 

 beautiful colours with which they are fo elegantly painted ; for 



(tripped 



