1902 Butterfly -Hunting in the Alps 95 



The most characteristic individual, as it is also perhaps 

 the handsomest and largest of the truly alpine butterflies, 

 is Parjiassius apollo, and it is rare, indeed, even for people 

 v^ho have no interest in or knowledge of entomology, to 

 overlook it. The flight of apollo is the poetry of motion, 

 and, with its semi-transparent wings boldly spotted with 

 black and crimson (rarely yellow) ocellations, and its great 

 moth-like body furred with down, once seen it can never be 

 forgotten. The genus Parnassius is also remarkable in that 

 the females are provided with a sort of a pouch beneath the 

 abdomen, and are said to secrete a kind of wax not unlike 

 that of the bee. P. apollo, however, at higher altitudes, 

 gives place to the smaller but no less beautiful P. delius, 

 distinguished from the preceding by a lesser degree of trans- 

 parency, and the substitution of a primrose-yellow tint for 

 the white pervading the wings. But recent observations 

 made by Dr T. A. Chapman of delius and apollo seem to 

 prove beyond doubt that the two are in reality but one 

 species, presenting different features in different localities. 

 There is a legend that P. apollo once occurred in Scot- 

 land, and, as it is common enough in South and Central 

 Norway, there seems no reason why it should not inhabit 

 the Highlands. I say seems, because one of the most 

 remarkable facts in the distribution of species, other than 

 the occurrence at widely separated intervals already alluded 

 to, is the absence of certain insects from localities which 

 appear to be in every way suitable to their propagation 

 and development. Apparently it is not always a ques- 

 tion of food -plant, climate, absence of natural enemies, or 

 even of elevation. As I have said, many lowland species 

 with us, which do not ascend to the mountains, attain 

 considerable elevation in the Alps and flourish amazingly, 

 just as others which are coast species alone in England, 

 like the Glanville Fritillary {Melitcea cinxia), exist far 

 inland upon the Continent. Saxifrage and stonecrop are 

 not rare plants in Scotland ; the conditions of wind and 

 weather there are not unlike those of Norway, if the atmos- 

 phere is neither as dry, nor the frost and snow so intense 

 and prolonged, as in Switzerland. Yet the fact remains 

 that, despite frequent attempts, I believe both north of the 



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