At Prof. J, F. VAN Bemmelen's suggestion I decided to inves- 

 tigate how far this assertion holds good for different families. 

 My purpose was to find an answer to the following questions : 



1". Does a conformity exist between the different colours, 

 the pattern and the skin-relief of the caterpillars of the Rhopa- 

 locera, perhaps also of the Ileterocera? 



2°. Is it possible to deduce from this conformity a general plan 

 of the caterpillar pattern, and if so, does this possess a metameric 

 character ? 



3". Can any connection be found between the pattern of cater- 

 pillars and that of pupae, perhaps even with the colourpattern on 

 the body of the imagines? 



In thinking these questions over, I soon found that the following 

 points are connected with the former three, viz: 



4". Is the arrangement of the hairs on all segments the same 

 or is it different; and in the latter case, what are the relations 

 of these differing segments in other anatomical respects? 



b'^. Is the arrangement on one individual in all stadia the same ? 

 6". Have all the individuals of one species the same pattern? 

 Not until I had solved these last questions, could I expect to 

 find an answer to the first three. A priori I might expect a 

 certain constancy of the setal pattern. The investigations by 

 DE Meyere (1894) of the hairs of the mammals, by Megusar and 

 Werner of the spots on Salamandra maculosa^ gave rise to the 

 supposition that here also a constancy might be expected. In the 

 beginning of August 1914, I was not yet acquainted with the 

 extensive literature on the setae of the caterpillars. Spuler's remark 

 (1910, p. VII) did not make me think that the primary pattern 

 would be maintained with such pertinacity. 



The 6tt question I could drop very soon, as it appeared that 

 the fluctuation or individual variation (Plate, 1914, p. 148) is 

 so insignificant, that it might practically be neglected. This 

 fact apparently so simple, indicates already the great constancy 

 of the pattern of caterpillars (see however Papilio machaon). During 

 my investigation it turned out that not all the colours of cater- 



