438 Mr. Vonlton's further experimcid^ upon 



occupy depressions in the cuticle The large black 



pigment patches and spots are nearly always abundant. 

 .... The ground-colour may be of various tints — greyish 

 green, orange, yellow, or a peculiarly opaque-looking 

 greyish white. The amount of the grey colour, always 

 present, subdues the differences between these tints, so 

 that they resemble each other far more than the above 



description would seem to imply The following 



subdivisions are well marked, although transitional 

 varieties occur : — 



(a) The darkest forms, with greyish green, orange, 



yellow, or wliite ground-colour. 

 (/3) Intermediate forms, with lighter ground-colour 



of the same tints, and smaller and fewer 



pigment patches. 

 h) The lightest of these forms, with ground-colour 



still greyish, but the pigment patches very 



small relatively to ice) or (^). 



(2) The last sub-division passes into this variety, in 

 which the ground-colour is an opaque-looking whitish 

 yellow, often with greenish areas on part of the surface, 

 the pigment patches being very small The greyish 

 hue is lost, because of the minute size of the dots in the 

 ground-colour. Hence the effect is very light 



(3) A still more abnormal, very well-marked, variety, 

 possesses a deep transparent-looking bluish green 

 ground-colour, in which the minute dots and the large 

 patches are even less developed than in the last degree. 

 An opaque whitish-yellow band, like the ground-colour 

 in (2), occupies the anterior half of that part of the tlnrd 

 abdominal segment which is seen dor.jall}^ and extends 

 on to the posterior part of the segment in front ; and the 

 dorsal surfaces of the abdominal segments behind the 

 third are often mottled with the same colour 



The differences between the ground-colours of (1), (2), 



and (3) are very well-marked " (Phil. Trans., 1887, 



B, pp. 409, 410.) 



The words '* normal " and " abnormal " are only used 

 above in the sense of usual and unusual in the wild state. 

 Every form is normally produced by its appropriate 

 background, and it is only because the wild pupre are 

 almost invariably found on stone or brick walls, and on 

 palings, that they assume the appearance of (l)s rather 

 than (2)s or (3)8. 



