The Origin of the Markings of Caterpillars. 237 



three small white spots (Fig. 56). The cater- 

 pillar likewise possesses a marking of which the 

 adult species of the genus retain only a trace, 

 viz., a well-developed, pure white subdorsal line, 

 which is crossed by the six anterior oblique stripes, 

 and uniting with the upper part of the seventh 

 extends to the caudal horn. 



I long believed that the markings described were 

 first acquired in the second stage, as I was possessed 

 with the generally accepted idea that the changes 

 of form and colour in insects could only occur at 

 the period of ecdysis. I at first thought that the 

 moult had escaped my notice, and I was only 

 undeceived by close observation of individual 

 specimens. 



Second Stage. 



The first moult took place after five days, the 

 larvae being 1.4 centimeters in length. Only un- 

 important changes of marking are connected there- 

 with. The subdorsal line loses much in thickness 

 and definition, and the first and last of the oblique 

 stripes become considerably broader than the 

 intermediate ones (Fig. 57). The green ground 

 colour and also the stripes acquire a yellowish 

 hue. 



On the other hand, there occur changes in form. 

 The head, which was at first rounded, becomes of 

 the characteristic triangular shape, with the apex 

 upwards, common to all the species of the genus, 



