78 SCIENCE PROGRESS 



does not appear to enter into the consideration of diurnal 

 Lepidoptera, nevertheless in view of the great conspicuousness of 

 red in very high illumination on account of its great pene- 

 trating power, it is necessary to inquire whether insects which 

 present this colouration are shade or sun-loving : more especially 

 because it is considered that to appear conspicuous at great 

 distance would be of no advantage to any animal : all the 

 requirements of warning or distinctive colouration (Swynner- 

 ton, Ibis, 1 91 6, vol. iv. p. 265) are fulfilled at comparatively 

 short distance. It follows that red should be used for this 

 purpose in forest and shade-loving insects, and as will appear 

 later, blue in those frequenting open and sunny localities. It 

 has been mentioned that a red and green pattern will be incon- 

 spicuous beyond the blending distance ; but close at hand red 

 against green will be very conspicuous : thus such a colouration 

 would fulfil the requirements for " warning " or " distinction." 

 In Papilio, red occurs associated with blue and yellow, and in 

 Sabaria, Pangeranopsis, and Achillides associated with green. 



To return to the question of illumination, the majority of the 

 Parnassiinae live upon open grassy mountain tops, close to the 

 snow line, where the lighting is likely to be poor, though this is 

 by no means certain ; much will depend upon the prevalence of 

 mist. Out of the thirty-nine Papilioninse presenting small red 

 areas, ten are mentioned in the text as inhabiting forests and 

 jungle, four living in the open, and in the remainder the 

 habitat is not given. The following are the four species which 

 are mentioned as inhabiting open situations ; it is noteworthy 

 that they present far less red than is usually the case : 



TABLE NO. 2 



Sainia protenor . a single eye-spot close to the posterior angle of the hindwing. 



Orpheidea demoleus a single spot close to the posterior angle of the hindwing. 



Papilio asiatica . a single spot close to the posterior angle of the hindwing. 



Achillides paris . a single eye-spot close to the posterior angle of the hindwing. 



There is other evidence that these insects are conspicuous : 

 (1) they are not baskers, as many Lepidoptera, but prefer to 

 settle in shady places ; (2) after settling they often depress the 

 forewings so as to cover the red-spotted hindwings ; and (3) 

 lastly, they belong to a group which is considered to be relatively 

 unpalatable. 



(To be continued) 



