The Origin of the Markings of Caterpillars. 1 8 1 



central portion of the white spots at the same time 

 becomes of a peculiar violet-brown colour inclin- 

 ing to yellow above, the peripheral region alone 

 remaining pure white. 



Of the subdorsal line only traces are now to be 

 recognized, and these are retained, with almost 

 unchanged intensity, sometimes into the last stage, 

 remaining with the greatest persistence on the 

 three front and on the penultimate segments, 

 whilst on those containing the eye-spots, i. e. y the 

 fourth and fifth, not a trace remains. At the 

 present stage the peculiar mingling of colours 

 becomes apparent over the whole of the upper 

 surface ; the green is no longer uniform, but a 

 mixture of short and gently sinuous, dark-green 

 striations on a lighter ground now appear. On 

 the sides of the caterpillar these stripes, which 

 are at first indistinct, but become more strongly 

 pronounced in the next stage, are arranged 

 obliquely on the spiracles, with the lower portions 

 directed forwards. 



Fifth Stage. 



The fourth moult occurs 7 8 days after the 

 third, the caterpillar being 4 5 centimeters in 

 length. Whilst all the specimens hitherto observed 

 were with one exception light green, they now 

 mostly changed their colour and became dark brown. 

 In one case only did the brown colour appear 

 in the previous (fourth) stage. The striations 



