THE SWALLOW-TAIL. 31 



figures are drawn from specimens collected in Wicken Fen in 

 October, 1905. Occasionally a much darker, nearly black, 

 form is found. 



This butterfly was known to Petiver and other early 

 eighteenth-century entomologists as the Royal William. There 

 is every reason to believe that at one time it was far more widely 

 distributed in England than it now is. Stephens, writing in 

 1827, states that it was formerly abundant at Westerham, and 

 gives several other localities, some very near to London. 



During the last twenty-five years or so, the butterfly has been 

 seen on the wing, from time to time, in various parts of the 

 Southern and Midland counties. Caterpillars have also been 

 found at large in Kent. Possibly attempts may have been 

 made to establish the species in certain parts of England, and 

 the presence of odd specimens in strange places may thus be 

 accounted for. Or such butterflies may have escaped from 

 some one who had reared them. 



On the Continent the butterfly is common in woods as well as 

 in meadows, and even on mountains up to an elevation of 5000 

 feet. It occurs also, but less commonly, at much higher alti- 

 tudes. It therefore seems strange that in England it should be 

 confined to the low-lying fens of Norfolk and Cambridgeshire. 

 Such is the case, however, and a journey to one or other of its 

 localities will have to be made by those who wish to see this 

 beautiful creature in its English home. 



It may be added that the geographical range of the butterfly 

 extends eastwards through Asia as far as Japan. A form, 

 known as the Alaskan Swallow-tail, is found in Alaska. 



The following ten species belong to the Pierinae, another 

 sub-family of Papilionidse. 



