The Origin of the Markings of Caterpillars. 339 



Rubi shows that the lizards were from the first 

 prejudiced against such larvae, the prejudice only 

 being overcome on actually trying the specimen 

 offered. A subsequent observation which I made 

 after arriving at this conclusion, is most note- 

 worthy. After the lizard had learnt by experience 

 that there might be not only distasteful caterpillars 

 (E. Jacob&ce), but also palatable ones banded with 

 black and yellow (B. Rubi), it sometimes tasted 

 the Jacobcece larvae, as if to convince itself that the 

 insect was actually as it appeared to be, viz., un- 

 palatable ! 



A striking appearance combined with a very 

 perceptible and penetrating odour is occasionally 

 to be met with, as in the caterpillar of the common 

 Swallow-tail, Papilio Machaon. I have never seen 

 a lizard make the slighest attempt to ' attack this 

 species. I once placed two large specimens of 

 this caterpillar in the lizard vivarium, where they 

 remained for five days, and finally pupated un- 

 harmed on the side of the case. 



I have recorded these experiments, although 

 they do not thus far relate to Sphinx-caterpillars, 

 with the markings of which we are here primarily 

 concerned, because it appeared to me in the first 

 place necessary to establish by my own experi- 

 ments that signals of distastefulness did occur in 

 caterpillars. 



I now come to my unfortunately very meagre 

 experience with Deilephila larvae, with only two 



z 2 



