78 Colouration in Animals and Plants. 



lost its scalloping. In the fore-wing gome of the black bands and 

 spots are suppressed or extended, and the extensions end rigidly 

 at nervules. The dark colouring of the hind-wings has spread over 

 the whole wing. We thus see that the decoration, even in varieties 

 called abnormal, still holds to structural lines, and is a development 

 of pre-existing patterns. 



No one can have examined large series of any species without 

 being impressed with the modification of patterns in almost every 

 possible way. For instance, we have reared quantities of Papilio 

 Machaon, and find great differences, not only in the pattern, but in 

 the colour itself. A number of pupae from Wicken Fen, Cambridge- 

 shire, were placed in cages, into which only coloured light could 

 fall, and though these experiments are not sufficiently extended to 

 allow us to form any sound conclusions as to the effect of the 

 coloured light, we got more varieties than could be expected from 

 a batch of pupae from the same locality. The tone of the yellow, 

 the quantity of red, the proportion of the yellow to the blue scales 

 in the clouds, varied considerably, but always along the known and 

 established lines. 



The variations in the colour of Lepidoptera has been most 

 admirably treated by Mr. J. Jenner Weir in a paper, only too short, 

 read before the West Kent Natural History Society.* He divides 

 variations into two sections, Aberrations or Heteromorphism, and 

 constant variations or Orthopaicilism, and subdivides each into six 

 classes, as under : 

 Heteromorphism. 



Albinism ... ... white varieties. 



Melanism black do. 



Xanthism ... ... pallid do. 



Sports ... ... or occasional variations not in- 



cluded in the above. 



Gynandrochomism ... females coloured as males. 



Hermaphroditism ... sexes united. 

 Orthoptccitism. 



Polymorphism ... variable species. 



Topomorphism ... local varieties. 



Atavism ... ... reversion to older forms. 



Dimorphism two constant forms. 



Trimorphism three do. do. 



Horeomorphism ... seasonal variation. 

 * Entomologist, vol. xvi., p. 1G9, 1883. 



