410 DK. J. 0. MOTTRAM ON 



Flowers are, as a rule, circular ; their patterns consist of seldom 

 more than two components, one being concentrated in the middle- 

 in the form of a circle, and there is usually a strong contrast in 

 tone (and colour) between the two components. 



It might be thought that these arivangements of pattern in 

 jBowers were due to convenience of growth ; but the eccentric- 

 shapes and patterns assumed where special animals are sought 

 for the purpose of fertilisation indicate that flowers are not 

 forced by growth to assume the circular shape and eye-spot 

 pattern. 



In conclusion it may be said that, except in the case of flowers, 

 white-centre dark-margin eye-spot patterns are rarely to be seen 

 in Nature and are almost always isolated. Sunlight penetrating 

 through foliage on to broken ground and sky views tli rough 

 foliage a.re the two most common causes. As regards flowers,, 

 eye-spot patterns are very common, but the centre is as often 

 darker than the margin as vice versa. 



It follows that animals presenting this type of pattern must 

 be considered to be conspicuous in Nature. 



Part II. 



Having by experimental methods defined the types of pattern 

 which render an object conspicuous, attention was turned to the- 

 animal kingdom to discover whether exampleKS of these types 

 could be found and, if present, what was their distribution. 

 Search was made among the Lepidoptera because their wings offer- 

 a plain, flat patterned surface, and thus the complicating fa,ctor 

 of solidity is avoided. Rather than search through a large 

 amount of material, it was decided to deal thoroughly with a 

 definite amount, viz., the Indian Lepidoptera. Moore's 'Lepi- 

 doptera Indica ' was the work chosen, because of its good coloured 

 illustrations of each species. On glancing through these plates 

 several types of pattern were found which previous consideration 

 showed would render these insects conspicuous. The first type 

 to be dealt with is shown in text-fig. 17. It can be seen that 

 the pattei'u consists of a central white, or light yellow, area 

 surrounded by a black margin, so that the four wings combined 

 present an irregular, white -centred, black-margined pattern. 

 The margin of the wings is, except in two cases (noij. 1 and ^), 

 not scalloped. The black marginal band is sometimes bi-oken 

 by small spots or bands of light tone, but only in the case of' 

 no. 2 is the margin interrupted by pattern. 



This type of pattern presents, therefore, those characters which 

 previous consideration has shown must render the insect con- 

 spicuous in Nature : the table on p. 412 gives its distribution 

 among genera of the Indian Lepidoptera. 



Scdatttra (text-fig. 17, 7) and Acidalia (no. 2) do not conform 

 to the type in several respects. In Salatura the centre white^ 



