Adjustment of colour in various 'pupx, etc. 438 



The Blach papers, both "surface papers" and tissue- 

 papers, gave the same results as Mr. Merri field's, and 

 those previously recorded (E. B. Poulton in Trans. Ent. 

 Soc. Lond. 1892, pp. 461 — 464), and the same was true 

 of the yellow papers (surface and tissue) and yelloiv le7io, 

 all of which were typical ; the v:hite paper, and the white 

 opal glass. The deep orange paper was similar to that I 

 have previously used, and very different to Mr. Merrifield's. 

 The following backgrounds had not been examined 

 before : — 



A dull surface of metallic zinc (perforated) gave a dim 

 continuous spectrum (general, but no selective absorp- 

 tion), 



Salmon pink surface paper. A very faint absorption of 

 the blue was all that could be seen. The blue also looked 

 redder, an effect which may have been due to the stray 

 white light reddened by selective absorption in the 

 paper. 



Violet paper. Much of the blue end, and considerable 

 red were reflected. There was an absorption band be- 

 tween the green and the blue, and the yellow, orange, 

 and green were much absorbed. 



28 a 



