The Origin of the Markings of Caterpillars. 335 



I now proceed to the consideration of the bio- 

 logical value of incomplete eye-spots, or, as I have 

 termed them, ring-spots. Are these also means 

 of terrifying, or are they only signals of distasteful- 

 ness ? 



I must at the outset acknowledge that on this 

 point I am able to offer but a very undecided 

 explanation. The decision is only to be arrived 

 at by experiments conducted with each separate 

 species upon which one desires to pronounce 

 judgment. It is not here legitimate to draw 

 analogical inferences, and to apply one case to all, 

 since it is not only possible, but very probable, that 

 the biological significance of ring-spots changes in 

 different species. Nothing but a large series of 

 experiments could completely establish this. Un- 

 fortunately I have hitherto failed in obtaining 

 materials for this purpose, I would have deferred 

 the publication of this .essay for a year, could I have 

 foreseen with certainty that such materials would 

 have been forthcoming in sufficient quantity during 

 the following summer ; but this unfortunately de- 

 pends very much upon chance, and I believed that 

 a preliminary conclusion would be preferable to 

 uncertainty. Perhaps some entomologist to whom 

 materials are more easily accessible, may, by 

 continuing these experiments, accomplish this 

 object. 



The experiments hitherto made by other ob- 

 servers, are not sufficient for deciding the question 



