106 OCCASIONAL PAPERS. 



one or two years, or even longer, we may not see a 

 single specimen ; another year they come out by twos 

 and threes, but every now and then there is a great 

 swarm of them. No one can yet account for it ; no 

 one knows whether it is through extensive immigra- 

 tion, or through circumstances more than usually 

 favourable to their multiplication on our own soil. 

 It is one of the many knotty but interesting questions 

 Nature sets before us, and almost defies us to answer. 

 Perseverance, however, and patience on our side will 

 doubtless in the end write down a correct answer to 

 this, as has been done to other problems. A few 

 years ago (in 1872) we had a " Camberwell Beauty 

 Year," when this large insect, noted as one of the 

 more than usually rare British butterflies, and indeed 

 generally referred to as rapidly disappearing like the 

 Great Copper, was taken in many parts of the coun- 

 try, though not, it is true, in any great numbers. 

 Folkestone, however, yielded several specimens. The 

 Bath White and the Queen of Spain were abundant 

 the same year. And so it is with other insects from 

 time to time; 



As Edusa is of great local interest, I thought a few 

 remarks concerning the butterfly, its appearances, 

 and its variations in form and colour, would not be 

 unacceptable to our members. By the kindness of 

 Mr. Giles and Mr. Blackall we have before us some 

 fine specimens as illustrations. The family to which 

 it belongs is known as the Rhodoceridce, or Redhorns, 

 from the roseate tinge you will observe on their 

 antennae. It is not a large family in our island, in- 

 cluding only the following members : The Clouded 

 Yellow (Colias Edusa), the Pale Clouded Yellow (C. 



