2 



STRUCTURE OF THE LEPIDOPTERA 



are the scales that led the immortal naturalist to invent the some- 

 what long but useful term Lepidoptera. 



The very next time the opportunity offers itself, dust off a little 

 of the mealy powder with a small and very soft brush on to a 

 strip of white paper or a slip of glass, and examine it with a 

 powerful lens or the low power of a compound microscope. What 

 a sight you will then behold! Each little particle of dust is a 

 beautifully formed scale, stamped with a number of minute 

 rounded projections, and often displaying the most gorgeous colours. 

 A great variety of designs and tints are often exhibited by the 

 ' dust ' from a single wing. Take, for instance, for your inspection, 

 scales from the wing of one of our commonest insects, the Small 



Tortoiseshell Butterfly (Plate 

 III), and you will be surprised 

 at the pleasing contrasts. But 

 when your curiosity leads you 

 to deal with others in the same 

 manner, the varied display of 

 forms and colours is simply 

 amazing. 



In order that we may learn 

 still more of the structure of 

 the wings of the Lepidoptera, 

 we will examine a portion of 

 one from which some of the 

 scales have been removed, 

 again bringing the lens or the 

 microscope into our service. 

 We now see that the scales 

 are arranged in rows with great regularity on a thin and trans- 

 parent membrane, which is supported by a system of branching 

 rays. And the membrane itself, in parts which have been laid 

 bare, is marked with regular rows of dots the points at which 

 the scales were originally attached by means of short hollow 

 rods. 



The framework that supports the thin membrane we have 

 spoken of as consisting of a system of rays, but to these the terms 

 veins, nerves, nervures, or nervules are more commonly applied by 

 various naturalists. We cannot do better, however, than adhere 

 to the name originally used, for the structures in question do not 

 perform the functions of veins, though at first they contain blood. 



FIG. 2. PORTION OF THE WING OF A 

 BUTTERFLY FROM WHICH SOME OF 

 THE SCALES HAVE BEEN REMOVED. 



