The Origin of the Markings of Caterpillars. 



211 



easily explained as cases of arrested, or retarded 

 development. Thus, the subdorsal line often dis- 

 appears earlier, and is only present in the fourth 

 stage as a feeble light stripe. 



DEILEPHILA GALII, FABRICIUS. 



The markings of this species appear to be 

 developed in a precisely similar manner to those 

 of D. Vespertilio. The adult larva, as in the last 

 species, shows no trace of a subdorsal line. A row 

 of large black spots, each having an irregular 

 round, yellowish-white nucleus, is situated on an 

 olive-green, blackish-brown, brown, or dirty yellow 

 ground. I have, unfortunately, also in this case 

 been unable to procure fertile eggs. There is, 

 however, one figure of a caterpillar, 2.5 centimeters 

 long, by Hiibner, which is of a light-green colour, 

 and has five longitudinal lines ; one dorsal, two 

 subdorsal, and a spiracular line. The subdorsal 

 is white, and bears in the place of the ring-spots 

 small red dots, whilst the line itself is bordered 

 with black where the red spots are situated. 

 Hiibner has probably figured the third stage, so 

 that we may venture to conclude that in the second 

 stage there is a subdorsal line either quite free 

 from spots, or only showing such feeble rudiments 

 as are to be seen in the second stage of 

 Vespertilio. 



I found two specimens in the fourth stage in 

 the Upper Engadine. One of these (Fig. 45) 



p 2 



