96 EVENINGS AT THE MICROSCOPE 



power of 600 diameters (as I have now put on), you per- 

 ceive that, in the first place, the lines are not straight nor 

 parallel, but curve irregularly, and are often branched; 

 and, in the second place, that they are not uninterrupted, 

 but made up of a series of successive wedge-shaped warts, 

 which lie nearly flat, but project a little at the larger end, 

 where each overlaps the next. The scale we are looking 

 at measures -0014 inch in length, and -0009 in width; here 

 the marks are well defined; here are smaller scales -0008 

 in length by -00035 in width, but these are more dim and 

 difficult to resolve. 



The beautiful and extensive order called Lepidoptera 

 or Scale-winged, par excellence, including the gay tribes 

 of Butterflies and Moths, presents us with many exceed- 

 ingly interesting varieties in these singular coverings. The 

 study of these might be almost as wide as the immensity 

 of species; I can only show you a few examples. 



Here are specimens from the pretty little white Five- 

 plume Moth (Pterophorus), so common in meadows in sum- 

 mer. The general shape of the scales from the body and 

 wings is that of a willow- leaf, some singly pointed, but 

 more cut at the tip into two, three, or four notches. 

 Those from the legs are longer and slenderer in propor- 

 tion; and among the others from the wings, there are 

 some which take the form of hairs, which send forth one 

 or more branches from one side, that form a very acute 

 angle with the main stem. The scales proper are all 

 marked with longitudinal lines, very minute and close, 

 but they mostly bear a central band, and sometimes a 

 marginal one on each side, of spots set in sinuous lines 

 like the bands on a mackerel's back; these are probably 

 composed of pigment-granules. 



