72 



SCIENCE PROGRESS 



The Consideration of Black 



Referring to diagrams Nos. i and 2, it is seen that black is, 

 after brown, the most frequently found and that it is very 

 largely laid down in small areas (91 per cent.). In the majority 

 of cases it is associated with small areas of white, in the pro- 

 duction of eye-spots and marginal patterns. It is also largely 

 used in the form of spots upon yellow or orange insects as in the 

 Argynninae. It] has been previously shown (loc. cit.) that 

 small black used in this way must be considered an incon- 

 spicuous arrangement. 



Small areas of black are used in conjunction with large 

 areas of yellow, orange, brown, white, and blue to render con- 

 spicuousness in the form of a border which protects the colour 

 from admixture with the insect's background, as fully explained 

 on p. 74. Used in this way, the conspicuousness may be said 

 to depend upon two distinct factors : ( 1 ) the production 

 of a pattern of two components, (a) the central light in tone, 

 (b) the outer dark, which has been shown in a previous paper 

 (P.Z.S. 1 91 6, p. 402) to be the most conspicuous arrangement 

 of tones which an object can present ; and (2) the protection 

 of a conspicuous central colouration from admixture with the 

 colours of the insect's background (see p. 74). 



Moderate areas of black are most often found as a wide 

 marginal band similar to the arrangement just described, as in 

 the Nymphalinae, genus Haridra. 



TABLE NO. 1 



Species. 

 PAPILIONIN^E. 



1. Ornithoptera ceberus 



2. O. heliaconoides . 



3. Sainia protenor 



4. Laertes pammon (normal form) 



Extent of Black Colouration, 



whole of forewing. 

 whole of forewing. 

 whole of hindwing, except small red 



spot, 

 whole of forewing and half of hind. 



5. Byasa bootes whole of forewing. 



NYMPHALINAE. 



6. Prothoe regalis 



7. Kaniska canace 



8. Euvanessa antiopa 



whole of hindwing and half of fore, 

 both wings, except for blue bar across 



both wings, 

 whole of centre of both wings outlined 



with band of buff. 



