718 EXTERNAL ANATOMY OF INSECTS. 
ascribes to the pectens of scorpions, they must be in- 
struments of excitement. 
And now, after this long discourse on the External 
Anatomy and structure of these little beings, you may 
think perhaps at first that the subject is exhausted ; and 
that I must have discovered and described every part 
and every variation of every part of the crust of an insect. 
But when you go on to reflect what a comparatively 
small number of these creatures have fallen under my 
examination, and in those, after all my laborious and 
painful researches, from my limited faculties and other 
imperfections of our common nature, how much will 
probably have eluded my notice, you may conclude that 
thousands of facts still remain concealed to reward the 
patient assiduity of future investigators. Such are the 
immensity and variety of the works of the Creator in 
this department, that it would require a long life, and 
fill volumes upon volumes, to discover and give a de- 
scription of all the peculiarities of structure of the insects 
that are already known; and could all that exist be so 
studied and explained in full detail, the library that the 
Calif Omar ordered to be burned at Alexandria could 
scarcely have contained more books than would be re- 
quired to receive the results. But ‘who is sufficient 
for these things * ?” This is a question that the most able 
and most experienced physiologist must often feel dis- 
posed to put to himself when, lost in the intricate laby- 
rinth of the works of his Maker, he sees all things ar- 
ranged, ‘ wheel within wheel,” in an order that he can 
~ 2 Cornice. 
