238 Studies in the Theory of Descent. 



and at the same time acquires two white lines, 

 which unite above at the apex of the angle. The 

 shagreening of the skin now also takes place, 

 and the red spot at the base of the horn is formed. 

 There appears to be at this stage a general 

 tendency for the suffusion of red, the thoracic legs 

 also becoming of this colour. 



Third Stage. 



The second moult occurs after six or eight days, 

 the marking only changing to the extent of the 

 subdorsal line becoming still more indistinct. This 

 line can now only be distinctly recognized on the 

 three front segments in a few individuals, whilst 

 in the majority it is completely absent. Some- 

 times the ferruginous red spots on the oblique 

 stripes now appear, but this character is not com- 

 pletely developed till the fifth stage. Out -of about 

 ninety bred specimens in which I followed the 

 entire development, only one possessed such spots, 

 and these were situated on both sides of the sixth 

 segment. 



Fourth Stage. 



The third moult, which takes place after another 

 period of six days, is not associated with any change 

 of marking. 



In this stage also I observed in one specimen 

 (not the one just mentioned) the ferruginous spots, 

 and again only on the sixth segment. On account 

 of the theoretical conclusions which may be drawn 



