536 Professor E. B. Poulton's Note on the 



pale patches are more opaque than others, but the first 

 stage in its typical form is not now to be found : the 

 species has passed beyond it. 



The under surface is in many respects very different 

 from the upper. The pale brown ground-colour has the 

 appearance of being overspread with a greyish bloom. 

 The dark line is wanting from the costal and inner 

 margins, but is far broader than on the upper surface 

 along the hind-margin of both wings, especially so on the 

 posterior. Centrally this broad marginal band passes by 

 a gradual transition into the ground-colour. 



The transparent areas themselves are, of course, the 

 same on both surfaces, but on the under-side of the hind- 

 wing there is developed around and between them a black 

 reticulated pattern with its meshes in some parts filled in 

 with unaltered ground-colour, in others with a darker 

 pigment, in others again with a much paler reflecting 

 pigment. Furthermore many of the pale-coloured areas 

 of the upper surface are distinctly darker on the under 

 surface ; especially those near the anal angle of both wings, 

 as can be well seen by comparing Fig. lA with Fig. 

 1. The whole effect on the hind-wing is to produce the 

 impression of a fungoid growth spreading in reticulate 

 fashion over the surface, and producing here and there at 

 points longest exposed to injury, the culminating effect of 

 transparency. The scattered masses of transparent areas 

 appear to become the centres of greatest injury in an 

 almost continuous network of decay. This effect, which 

 probably represents in considerable detail the results of a 

 leaf- attacking fungus, can in large part be made out in the 

 representation of the left hind-wing under-side (right side 

 of the figure) shown in Fig. lA, Plate XXXII. The trans- 

 parent meshes of the moth may represent actual holes in a 

 leaf, or its transparent cuticle filling in the meshes of a net- 

 work whose strands are the resistant fibro-vasular bundles. 

 The latter appears to be the more probable interpretation. 



The most characteristic feature on the under surface of 

 the fore-wing is the development of large patches of dark 

 pigment which appear to stand out in low relief This is 

 especially the case with the largest and most prominent 

 patch placed a little below the centre of the wing and 

 distinctly seen, as indeed are all the others, on Fig. lA of 

 the accompanying plate. Except in the case of the small 

 irregular dark areas near the apical and the anal angles, 



