The Origin of the Markings of Caterpillars. 223 



In this last position this line is somewhat widened, 

 and a long, diffused, rose-red spot can there be 

 recognized upon it (Fig. 58 A). The black "ground- 

 area " present in the fifth stage is as yet absent, 

 and the spot is not so sharply separated ante- 

 riorly from the subdorsal line as it becomes later. 



From these observations we might venture to 

 expect that in the third stage of Hippophaes, the 

 subdorsal line would also be free from this spot 

 on the eleventh segment, and it is possible that in 

 the second stage this line is itself absent. 



THE GENUS DEILEPHILA : SUMMARY OF FACTS AND 

 CONCLUSIONS. 



Regarding only the adult larvae of the species 

 of Deilephila, these represent in their five groups, 

 five stages in the phyletic development of the 

 genus ; but if we also take into consideration the 

 developmental history, two more stages must be 

 added, viz., that in which the caterpillar possesses 

 no particular marking, as was found to be the case 

 in the first stage of the development of D. Euphor- 

 bia and D. Dahlii ; and a second stage with a sub- 

 dorsal line, but without any ring-spot formations. 

 Seven stages of phyletic development must there- 

 fore be distinguished. 



Stage i. No species with entire absence of 

 marking in the adult form now occurs. 



Stage 2. A subdorsal, accompanied by a spira- 

 cular line, extends from the caudal horn to the 



