146 HALF-HOURS IN THE GREEN LANES. 



scales of a butterfly's or moth's wing. He may 

 never have heard of such scales, but when we tell 

 him we simply mean the coloured dust that powders 

 his fingers after handling a butterfly, and that this 



Fig. 97. Fig. 98. 



Scales of Pirns brasswx, X 450. 



dust when placed under the microscope assumes a 

 distinct form or shape, which varies according to the 

 species of butterfly from whose wings it has been 

 taken he may feel inclined to experiment. Indeed, 

 as regards their wings, butterflies and moths differ 

 from dragon-flies, beetles, &c., chiefly in having these 



