INSECT VARIETY. 117 



of some hard parts at the hasal portion of the wing-s. Prepos- 

 sessed with this idea, I submitted specimens of the wing-s cut 

 from the male and female of either of these to an excellent 

 microscope. And I then found a minute file or serrature (lima) 

 came at once to view, situated on the anal vein (Plate IV., 

 Fig. 1, I) at its base, and running along- it for one-third of its 

 leng"th, for which distance it is tumid, spindle-shaped, and bare 

 of scales. In the case of the Peacock, and I believe also of the 

 Small Tortoiseshell, it was much more strong-ly developed in the 

 female than the male, and the vein had a blacker, firmer consis- 

 tence. The vein that clasps this notched or filed one when the 

 wing-s are rubbed tog'ether is not difficult to find in the costal 

 vein of the hind wing- (Plate IV., Fig. 1, s), recognisable by a 

 raised surface, curved outwards, with a smooth bevel above 

 where it comes in contact with this filed vein ; but it likewise 

 only presents this character at the base, for if we trace it out- 

 wards, we soon notice its upper surface to sink in a series of 

 sharp notches beneath the feathery scales. But this is not all ; 

 in each of these butterflies there is an organisation which I 

 would compare to the mirror of the males of the Leaf-crickets in 

 structure and object, for we find at the fore-side of the costal 

 vein the wing-membrane is bare in a little circular patch {sm) 

 which is embossed, a provision, I conclude, to impress the 

 musical tremors arising from the friction of the filed vein on 

 the air. 



This genus, characteristic of the group of the Nymphalidse, 

 it will be seen has the organ of stridulation placed inversely 

 from what we find it in Papilionidae ; in the Lyeaenidse the 

 adjustment seems the same. Mr. A. R. Wallace, in a paper on 

 the Butterflies of the Amazon Valley, says, regarding the 

 indigenous Theclse"^ — " They have a very peculiar habit of moving 

 the two lower wings over each other in opposite directions, 

 giving an appearance of revolving discs." The phenomenon is 

 also observed of certain Hair Streaks in the Isthmus of Panama 

 by Mr. T. Belt, who relates that on his arrival at the small town 

 of Tierrabona he saw, " on wet muddy j)laces near the stream, 

 groups of butterflies collected to suck the moisture. Among 



* Endymion, Marsyas, Etolus, Pholeus, Sfc. 



