AND OF LIGHT. 237 



fly in August in the neighbourhood of Antioch and 

 Jerusalem. Pupae kept at 5 to 8, however, yielded 

 the common Swiss and German form of butterfly ob- 

 tained from hibernated pupae. 



(2) Local forms and races such as occur constantly in 

 certain definite localities may be produced. For in- 

 stance, exposure of pupae of V. urticce (Small Tortoise- 

 shell) to warmth produced specimens somewhat similar 

 to the variety ichnusa, whilst cold produced some speci- 

 mens which strongly recall the North American V. 

 milberti, and others which were indistinguishable from 

 the northern variety polaris. Again, warmth acting on 

 pupae of V. cardui (Painted Lady), gave an extraordi- 

 narily pale form, like those found in very different 

 parts of the tropics. Cold, on the other hand, gave 

 specimens with a very recognisable darkening of the 

 whole insect, such as is exhibited by a form found in 

 Lapland. 



(3) There may arise forms of an entirely similar as- 

 pect to some which are also found exceptionally under 

 natural conditions, i. e., aberrations. For instance, 

 warmth, acting for a brief period on V. cardui, produced 

 a few specimens of the aberrant form elymi. Cold, 

 acting on pupae of V. io (Peacock), produced a variety 

 ab. fischeri, which exhibits a reduction in the number of 

 the blue scales on both fore and hind wings. In these 

 and other characters an approach to the type of V. 

 urticcu is perceived. Such observations as these sug- 

 gest that a large number of the aberrations occurring 

 in nature may have actually arisen through the influ- 

 ence of abnormal temperature conditions. 



(4) There may be produced phylogenetic forms; 



