CHAPTER VII 



THE COLOURS OF THE LEPIDOPTERA 



Insect Coloration and its General Relation to Physiology — 

 Pigments of Caterpillars — Intrinsic and Derived Pigments 

 — Mr. Poulton's Experiment — Meaning of Derived Pig- 

 ments — Other Characters of the Coloration of Caterpillars 

 — Colours of Butterflies, Pigmental and Optical Colours 

 — The Pigments of the Pieridae — Pigments of other 

 Butterflies — Origin of the Pigments of Butterflies — Con- 

 trast between the Pigments of Butterflies and those of 

 Caterpillars — Pigments and Mimicry. 



The colours of insects are in many cases so con- 

 spicuous that they have always attracted much 

 attention, and of late years few biological subjects 

 have been more keenly debated than the meaning 

 and uses of the tints and markings of caterpillars 

 and butterflies, bees and flies. The frequent simi- 

 larity in colour between insects and their environment, 

 or between insects not nearly related, or on the 

 other hand the exceeding conspicuousness of some 

 well-protected insects, are facts which are obvious to 

 every one, and which have therefore attracted wide- 

 spread interest. Until very recently, however, this 

 interest has been chiefly confined to the external 



