178 



On the Finer Structure of Butterfly and Moth Scales. 



By T. F. Smith. 

 (Read October 2&th, 1887J 



At the last Conversational Meeting of this Club I exhibited the 

 scales of Amathusia Horsfddii as showing the villi figured by Dr. 

 Royston-Pigott in the " English Mechanic." 



Allow me to say here that I know nothing about butterflies 

 beyond recognizing one when I see it flying, and then I am not 

 sure it is not a moth. But we are all familiar with the appear- 

 ance of the scales, and that, under suitable powers, they nearly all 

 present the same general appearance — longitudinal and cross- 

 ribbings. But this is only in a certain focus ; in changing the focus 

 the whole appearance alters, and the field becomes filled with 

 dots. I know nothing more unsatisfactory than to rise up from 

 the microscope in a state of fog and feel that you are no nearer to 

 a knowledge of the structure than when you sat down. This, 

 however, was the condition of my own mind until very lately, and 



I have no doubt it is also the condition of many other observers. 



The battle of the scales was fought out very fiercely about a 

 dozen years ago, when Dr. Royston-Pigott claimed to have dis- 

 covered beading in Podura and Lepisma scales, and, although very 

 little is heard of the matter now, it is not because it was settled, 

 but because the combatants ceased from sheer exhaustion. On the 

 Podura scales I have never detected the slightest appearance of 

 beading, but the other day, on Lepisma scales, I came across the 

 exact appearance figured in the ninth volume of the " Monthly 

 Microscopical Journal," and I have not the slightest hesitation in 

 asserting, first, that the appearance as shown in Fig. 4 of Plate 



II of that volume is faithfully portrayed, and, secondly, that it 

 is false. It is well to know sometimes where a reputation was 

 wrecked, and I beg leave to show you on the blackboard how it 

 happened. 



