29 



tors place upon it. The best chance of obtaining this remarkable 

 aberration is to collect the larva; and rear the butterflies. A friend 

 who accompanied me to Digne bred three beautiful specimens. 



Ariitolochia pistalochia and rotu/ida are, to all appearance, very 

 closely allied ; yet inrdisicaste will only eat the former and cassandra 

 the latter plant. There are thirteen species of Aristolochia occurring 

 in Europe, though not a single one is indigenous to Great Britain. 



Aristolochia dematltis (birthwort) is found in old gardens, but it is 

 not a native. The geographical distribution oi pistalochia and rotunda 

 corresponds with that of the respective butterflies. A. dematltis 

 (given by German authors as the food-plant of T. polyxena type) has 

 a range as far north as Central Europe, where the butterfly is 

 found. 



The genus Eiichlo'e^ of which there are eight well-defined species 

 occurring in Europe, is another very interesting group of butterflies. 

 The first three species — bekmla, be/la, and tagls — are somewhat allied 

 to the Pieridse in appearance, markings, and flight, yet in structure 

 they are very different, the wings being far more pointed and the 

 antennae much shorter. Their flight, like Plerls callldlce and P. 

 dap'ldlce, is rapid, and, like the Pieridse, each has a second brood. 

 Specimens of the second brood are larger than those of the first, the 

 reverse being the case, I believe, with butterflies in Northern Europe. 

 The remaining five species may be termed the " orange tips." Their 

 flight is by no means so rapid as that of the three preceding species. 

 They rest frequently on flowers, and allow themselves to be easily 

 captured. 



Before referring to the genus Euchloe I wish to make a few remarks 

 with regard to three species of Pieridas. Plerls callldlce is quite an 

 Alpine species, and is of wide distribution, occurring from the Pyre- 

 nees to Turkestan, where it assumes a larger form known as chrysldlce. 

 The markings, however, are precisely the same. Callldlce is found at 

 Gavarnie, in the Pyrenees, on the Jura Mountains, Basses Alps, 

 nearly all over the Swiss Alps, and in the Tyrol, but is not found in 

 Scandinavia. 



I have met with occasional specimens in the Saas Valley and other 

 parts of Switzerland, but only on one occasion commonly. On June 

 15th, 1885, this "mountain white" was flying in considerable num- 

 bers over the Rhone Glacier moraine at 5761 feet above the level of 

 the sea. Being very quick on the wing, its capture was not easy, as to 

 keep one's eye on the butterfly and the broken ground was a difficult 

 matter. The caterpillar feeds on mountain Cruciferge. 



Plerls daplldlce. — So much has been written about this species that 

 I scarcely like to refer to it. I have met with it in several localities 

 round the Lake of Geneva, and last year at Martigny, in the Rhone 

 Valley, but never in any numbers in Switzerland. It is not an un- 

 common species at Hyeres, but in my experience is not so abundant 

 as E. bella. P. daplldlce would appear to be rather commoner about 

 sixty miles north of the Mediterranean. 



