THE WHITE PLUME MOTH. 169 



the same relation to those of ordinary Moths, as do 

 the feather tans to those made of paper or other 

 fabric. In the Plume Moths, the wings are not 

 formed of a membrane stretched upon rays, but 

 each ray, or nervure, forms the stem of a separate 

 plume. In the lower wings, these nervures are 

 separated nearly to the base, but in the upper 

 wings are only partially separate. 



A very common species of this group is shown 

 on Plate XII. figs. 4 and 5, both figures being 

 of the natural size. The former of these is the 

 White Plume (Pterophorus pentadactylus), some- 

 times called the Phantom, or the Skeleton. 

 This very pretty Moth is snowy white, and is 

 very plentiful, coming out in the evenings and 

 fluttering softly along as if it were a snow-flake 

 borne by the wind. 



The second species is the Stone Plume 

 {Pterophorus lithodactylus), in which the wings 

 are stone-grey instead of white. 



The illustration in the next page is a figure of 

 the beautiful Twenty Plume Moth {Alucita 

 polydactyla), enlarged to twice its natural size. 

 This is the only British example of its genus, 

 and cannot be mistaken for any other Moth, 

 the numerous Plumes, amounting altogether to 



