CHAPTER VIII 



THE COLOURS OF INSECTS IN GENERAL AND OF 

 SPIDERS 



Optical and Pigmental Colours in Insects — Colours of the 

 different Orders of Insects — Colours and Pigments of 

 Orthoptera — Optical Colours of Neuroptera — Coloration 

 of Beetles — Pigments of Hemiptera — Colour Resem- 

 blances between Diptera and Hymenoptera — Contrast 

 between Coloration of Lepidoptera and other Insects — 

 General Aspects of Insect Coloration — Variation in 

 Colour: (i) Natural, (2) Artificially produced — The 

 Colours of Spiders : (i) Optical, (2) Pigmental — Develop- 

 ment of Colour — Variation in Colour — Colours of the 

 Sexes — Markings of Spiders. 



Among insects other than butterflies the colours 

 are often striking and beautiful, and are again 

 divisible into pigmental and optical. Probably, 

 as a rule, when an individual exhibits brilliant 

 colouring, this is mainly due either to pigment 

 or to structure, the two types of colouring being 

 rarely both conspicuous, at the same time. But 

 this is true only of the bright pigments, the dark 

 being common in insects displaying much structural 

 colour. This is due to the fact that the dark pig- 

 ments are present in excess only when the cuticle 



