EXTERNAL ANATOMY OF INSECTS. 649 



their intersection to form lozenges. With regard to the 

 position of the scales on the wing, they usually lie flat, 

 but sometimes their extremity is incurved : in the beau- 

 tiful Argynnis Vanilla; a very singular appearance of nu- 

 merous transverse ridges is produced by the extremity 

 of those scales that cover the longitudinal nervures of 

 the primary wings, except at the base, being recurved. 



But though the general clothing of the wings of Le- 

 pidoptera consists of these little scales, yet in some cases 

 they are either replaced by hairs or mixed with them. 

 Thus, in the clear parts of the wings of Heliconians, At- 

 taci, &c, short inconspicuous hairs are planted ; in a 

 large number of the Orders the upper side of the Anal 

 Area of the secondary wings is hairy ; in several Crepus- 

 culars [Sphinx Phoenix, &c), where there is a double layer 

 as before mentioned, the upper one consists of dense 

 hairs, except at the apex, and the lower one of scales ; 

 and in most of them the scales of the primary wings are 

 piliform, and the secondary are covered by what ap- 

 proach very near to real hairs ; many of the Attaci are 

 similarly circumstanced: the four wings oiA.Cytherea 

 are also covered externally with hair. 



7. Before I conclude this long diatribe on the organs of 

 flight of insects, I must not omit some notice of the infi- 

 nite diversity of colours with which their wings are often 

 variegated and adorned by the Creator, who loves to 

 delioht us by the beauty, as well as to astonish and awe 

 us by the immensity and grandeur of his works. Though 

 the wino-s in every Order exhibit instances of brilliant 

 and beautiful colouring, yet those of the Lepidoptera in 

 this respect infinitely excel them all, and to these, under 

 this head, after noticing a few in the less privileged Or- 



