CHEMISTRY OF INSECT COLOURS. 



115 







Pigment colours. Dissolve, 



Physical colours. 



Physical (?). 



leaving white wing ; but, 



Became bronze. 



Became bronze-brown, &c. 



in some cases, wing is 

 yelloived. 



Parthenos gambrisius, 



Argijnnis 



Papilio codrus 



above 



Livienitis procris 



P. agamemnon 



Hesperia sp. ? 



Parthenos gambrisius, 



P. policines 



Urania fulgens 



below 



P. antheus 





Ino statices 



[Eronia argia) 





I. globularice 



Halias prasinana 





Thecla rubi 



Moma orion 

 Dichonia aprilina 

 Larentia viridaria 

 Nemoria vernaria 

 Hemithea strigata 

 Metrocampa margaritaria 

 Tortrix viridana 

 Cidaria viiata]_ p. 

 G.psittacata J ^'' 



It may be noticed that in this table I have ignored one 

 species, E. cardamines, the green of which, as shown in my 

 original tables,* is invariably turned black by all reagents. The 

 omission here of so unique a species may cause surprise ; and, 

 indeed, were the colour of this really a true green, which green 

 becomes black by the action of my reagents, we should certainly 

 have a most interesting example to deal with. But, as a matter 

 of fact, the green of this species cannot be rightly reckoned as 

 green at all. My experiments have fully convinced me that Mr. 

 Cockerell was quite right in the statement made some time since, 

 in his article on Variation,! that the green of cardamines is 

 apparent only, being merely a mixture of black and yellow. This 

 entirely accords with my experiments : the slight amount of yellow 

 is rapidly dissolved and the black left standing only. Therefore, 

 although this wing, previously to all appearance green, remains 

 black, we cannot reckon that a green has been changed to black. 



Now, in discussing the character of green, the first point to 

 be noticed is that whereas in red we had indubitably a pigment 

 colour only, and in yellow and chestnut (yellow especially) had 

 no certain evidence of any "physical colour," here, in green, on 

 the contrary, we have indubitably both physical and pigmental 

 colours to deal with, as well as a class of colours that are very 

 probably physical, though it is scarcely possible to speak 

 decidedly about them at present. 



Let us first dispose of the physical greens, of which we have, 

 undoubtedly, examples in Urania fidgens, Parthenos gambrisius, 

 and the Hesperia sp. All of these are metallic colours, and, by a 

 prnctised eye, can be instantly and with certainty detected as 

 " physicaV colours. I think that I may safely venture to lay 



Entom. xxiii. 252. 



t Entom. xxii. 



