232 SECTION D. ARTHROPODA. 



SECTION D. ARTHROPODA. 



Tuesday, 23 August, in the Lecture Room of Comparative 

 Anatomy, at 2 p.m. 



Chairman, Dr Sharp. 



Secretary, M. Ch. Janet. 



Assistajit Secretary, Mr Cecil Warburton. 



The following papers were read : 



I. On the evolution of colour in Lepidoptera. 

 By Mr M. C. Piepers. 



It is my wish to speak briefly about an important phenomenon 

 that my studies in Lepidopterology have revealed. It is true the 

 greater part of these investigations have already been published, but 

 as this has been done in the German language, they are, I believe, 

 little known in England ; now it is precisely in that country that 

 I should wish to draw attention to these investigations, for England 

 and English-speaking America possess the greatest number of 

 Lepidopterologists. Allow me then to ask the favour of your 

 attention for a short time. 



My studies on the caterpillars of the Sphiugidae (the result of 

 which was published in the Dutch periodical, TijdscJirift voor Ento- 

 mologic, Vol. XL., in an article entitled, Ueber die Farbe ujid den 

 PolyjHorpJiismus der SpJiingiden-Raiipeii) have convinced me that 

 in the whole of this family the caterpillars are subject to a process 

 of change of colour, which must already have begun in the primi- 

 tive form before the division into the different genera and species. 

 Hence at present the original whitish-yellow colour passes through 

 green and brown of all shades into black ; and there also exist 

 intermediate colours such as red, loam-colour, etc. This change 

 prevails in all species, but in nearly all follows a different course. 

 The differences consist in the manner in which the colour changes 

 or in the time at which such a change takes place, so that some 

 species are already far advanced, while these changes have hardly 

 begun in others, and the majority stand between the two extremes. 

 This is evident on comparison of the colours of the adult caterpillars 

 with those of their earlier stadia of growth ; these presenting onto- 

 genetically their former phylogenetical stadia ; and still more so 



