208 Studies in the Theory of Descent. 



The larva is 18 millimeters in length, of a leaf- 

 green colour, and shows no trace of a subdorsal 

 line, but possesses the two rows of ring-spots, 

 which only differ from those of the succeeding 

 stages in the green colour of the " mirror." 



DEILEPHILA DAHLII, TREITSCHKE. 



I am familiar with numerous specimens in various 

 stages, collected in Sardinia by Dr. Staudinger, 

 and preserved by inflation. 



The first stage is blackish, and shows no kind of 

 marking ; thus agreeing with the corresponding 

 stage of Euphorbia. The second stage is unfortu- 

 nately not represented in Staudinger's collection. 



The third stage shows a row of ring-spots, which 

 are, however, connected by a very distinct and 

 sharply defined subdorsal line. In the fourth 

 stage a second row of (under) ring-spots is added, 

 whilst the subdorsal line generally at the same 

 time disappears. 



The caterpillar remains unchanged during the 

 fifth stage, when it shows a great resemblance in 

 marking to Euphorbia ; neither does it appear to 

 differ essentially from this species in colour, so far 

 as can be judged from preserved specimens and 

 single figures (in Duponchel and Hiibner). I 

 have, moreover, seen several larvae in the last 

 stage, and the subdorsal could be distinctly re- 

 cognized as a broad light stripe. 



Of the four groups, the second (that of Galii), 



