354 



BRITISH LEPIDOPTERA. 



green larva, and is represented in fig. 13 (x 3), and also in fig. 14 (x 5*25). The 

 latter figure being larger, it has been possible to introduce the shagreen-dots, which 

 were omitted from all the other figures of this stage. The distribution and 

 amount of the dark markings are sufficiently indicated in the figures. The easy 

 transition from the degree of darkness indicated in fig. 12 (the 8th larva of the 

 last division), to that shown in fig. 13, is very clear. The larger scale of fig. 14 

 has permitted the representation of two of the chief tubercles, which are quite 

 distinct upon most of the segments. These have the appearance of black points, 

 one above and one below each spiracle except the last, in which one is above 

 and one behind. The hairs which spring from them are long. The shagreen- 

 tubercles are generally darker on the dark parts of the larva, e.g., the horn. The 

 head is very black, and its green ground colour has become dark, while the 

 black markings have extended greatly. Its appearance irom the front is seen 

 in fig. 15 (X 9). The area above the subdorsal is now almost completely black, 

 the green ground colour being chiefly traceable along the median line. Although 

 the markings have the effect ol black at a little distance, and are thus represented 

 in the figures, a careful examination in a strong light on September 29th, 

 showed that all the dark markings upon the borders and above the subdorsal 

 are of a purplish -brown colour, but of so dark a shade that they appeared to 

 be black. On October 2nd, when the larva was in the resting-period before 

 ecdysis, this purplish tint had become more distinct, and it could now be 

 recognised everywhere except on the darkest places, viz.— the horn, upon 

 and below the anal flap, and upon the head. At this time there was also a 

 prothoracic dorsal-plate distinctly demarcated from the surrounding surface, 

 like that described in the 1st stadium, and shown in fig. 5. This structure also 

 became especially distinct in the resting-period of the next stage. In the 3rd 

 stage the plate was traversed by the subdorsal line, and hence became mottled 

 with white upon each side, while the plate regained its black colour below the 

 line. This appearance only became distinct during the resting-period, and is 

 not shown in figs. 13 and 14, which were drawn at an earlier period. 



The apparent black marks of the other larvae could also be 

 resolved into purplish-brown tints in a strong light, especially 

 towards the end of this stage. The caudal horn is still thorny and 

 distinctly bifid, although not so deeply or so widely notched as in 

 the last stage. The notch was uniformly present in the larvae. The 

 appearance of the horn of the 3rd stage, as seen from the front, is 

 shown in fig. 16 (x i4"5). The horn figured was one in which the 

 transparent zone was well marked ; it is quite straight, and held at 

 the angle shown in figs. 10-13. The results of this comparison of 

 the darkness and the shades of ground colour in this stage may be 

 expressed in the following tabular form ; the intervals between the 

 larvae indicate breaks in the transitional series : 



PALEST AND BLUEST. 



INTER- 

 MEDIATE. 



YELLOWEST AND DARKEST. 



The 10 pale larvse / 1 J 



23*— 4 — 

 of the last stage ( 10 ) 



The 7 dark larvse ) 

 of the last stage J 



5 6 

 2 3 



- - 7 - 8* - 9 - 



(dead) 



- 4* 5 6 - - - 7* 



I. 



II. 



III. 



The larvse with asterisks affixed were those represented in figs. 

 10, 11, 12, 13 (and 14). The divisions I, II, III indicate the new 

 arrangement, which was adopted on October 2nd, after the com- 

 parison of colours. If the larvae were arranged with reference to 

 the shade of ground colour alone, the following series would be 



