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of Limax agrestis I found at Bedford Park, and a white 

 Testacella scutulum found at Gibraltar, where the typical 

 coloured form seemed not to occur. 



Pascal described a very curious variety of Limncea pahistris 

 found in France, in which the soft parts, instead of being 

 darkly pigmented as usual, were semi-transparent and yellow, 

 while the buccal mass could be seen through, of a vivid rose 

 colour. This, apparently a case of non-development of pig- 

 ment in the soft parts, though the shell was fully pigmented, 

 remained unique, until my brother and Mr. F. G. Fenn went 

 down to Heme Bay a year ago, and brought back a number of 

 PJiysa fontinalis exhibiting precisely the same peculiarity of 

 a transparent yellow animal, with the pink buccal mass 

 showing through. It is notable that the albinism, of the 

 shell of P. fontinalis occurs at Heme Bay, but these with the 

 pigmentless soft parts had normal coloured shells. 



True albinisms among the Lepidoptera are very rare, 

 though cases of pale patches on the wings and partial arrest 

 of the development of pigment are not uncommon. 



Specimens of EpinepJiele ianira and E. tithoniis, in which 

 the prevailing colours are sienna-brown, dark brown, and the 

 black of the ocelli, will sometimes be found to lack entirely 

 the last two pigments, leaving in their place a very pale 

 ochre-yellow. Also, specimens are found in which brilliant 

 and metallic colours are replaced by white, such as Polyoni- 

 inatus plilcEcxs, var. schinidtii and Lyccena corydon, var. albescens. 

 Then there are the pale females of Colias, such as C. ednsa, 

 v. lielice, C. erate, v. pallida, and C. aurora, v. chloe, and also 

 various pale local varieties which occur in both sexes. 

 Probably these pallid varieties are caused, not by the absence 

 of the pigment-elements, but an arrest in their development. 

 Anyone who has bred Geonietra papilionaria from the pupa 

 cannot fail to have noticed the curious change that takes 

 place from brown to green in the wing-pigment, while the 

 insect is still within the pupa-case, but is just about to 

 emerge. Similarly, Pseudoterpna cytisaria sometimes appears 

 pale brownish, and sometimes green, and it is said that, all 

 being at first brown, only those that emerge in fine weather 



