2O4 Studies in the Theory of Descent. 



this line on the abdominal legs. These dots are 

 not only of value as a character for differentiating 

 the genera Deilephila and Chcerocampa^ but they 

 also play a part in the peculiar spot-marking which 

 will be shown later on. The ground-colour of the 

 caterpillar is now light green (Fig. 40), replaced 

 by black on certain parts. From the black 

 " ground-area " of the ring-spots, two black 

 triangles extend towards the posterior borders 

 of the segments, but usually without reaching 

 them. 



The ring-spots are not essentially changed, al- 

 though it may be observed that in most specimens 

 the shagreen-dots under each ring-spot are some- 

 what larger, and stand closer together than in 

 other places. In the following stage they become 

 fused into a second white " mirror," so that two 

 ring-spots stand one above the other, their black 

 ground-areas meeting. The formation of the 

 second ring-spot sometimes takes place in the 

 present stage (Fig. 42). 



The subdorsal line has now completely vanished, 

 whilst the spiracular-line 20 appears as a broad stripe 

 above the legs. The horn is yellow with a black 

 point, and the black spots on the head have in- 

 creased in size. 



10 To be accurate this should be designated the infra- 

 spiracular line ; but this term cannot be well applied except 

 in cases where there is also a supra-spiracular line, as, for 

 instance, in Anceryx (Hyloicus) Pinastri* 



