The Origin of the Markings of Caterpillars. 203 



Second Stage. 



The first ecdysis occurs after five days, and 

 with this there appears quite suddenly a very 

 complicated pattern. The ground colour is now 

 a light yellowish-green (Fig. 39), and on each 

 of the twelve segments, near the front border, there 

 is a pure white round spot in the middle of a large 

 black transverse spot. I shall designate these, in 

 accordance with the nomenclature employed for 

 Ch&rocampa> as the white " mirrors " on black 

 "ground-areas," both together constituting " ring- 

 spots," as distinguished from " eye-spots " proper, 

 in which a " nucleus," the pupil of the eye, is also 

 added. In many, but not in all specimens, very 

 distinct traces of a subdorsal line can be seen as 

 a light whitish stripe connecting the white spots. 

 The horn, the thoracic and prolegs, and some 

 spots on the head, are black. 



The caterpillars remain unaltered till after four 

 days, when, having a length of 1 7 millimeters, the 

 second moult takes place, bringing with it changes 

 quite as great as those which occurred with the 

 first. 



Third Stage. 



The caterpillar now assumes the shagreened 

 appearance which it possesses in the adult state. 

 Small white warts are arranged in rows from the 

 dorsal to the spiracular line, and again underneath 



