HYLES EUPHORBIA. 227 



was margined with red ; the red head and the dorsal stripe, &c, 

 were as in the other varieties. (2) The black variety had no sub- 

 dorsal wedge marks ; the first ring in each segment had a black 

 ground, the others a greenish-black ground, dotted and spotted 

 with bright sulphur-yellow above and white below ; very little of 

 the spiracular region was inflated, it was coloured crimson-red and 

 ochreous, the red in the middle gently blending with the 

 ochreous at each segmental division ; the anterior edge of the 

 second segment was yellow ; a large round black spot on the top 

 of each lobe of the crimson head. The anterior half of the anal 

 prolegs was black, the rest crimson ; the crimson dorsal stripe 

 quite narrow ; the anal flap was black, margined with crimson. 

 Buckler also describes a variety of this larva, brought home in 

 spirits from Cairo, by Jenner-Fust, which he received in May, 

 187 1, arid figured. This had the broad ring ot each segment 

 black, the ground colour of the other rings of the deepest 

 blackish-olive ; the head, the plate on the second segment, 

 the dorsal stripe, the legs, anal flap, and caudal horn were 

 blood-red. The double series of large spots was creamy-whitish ; 

 the upper rows of small dots pale yellow, the lower rows white ; 

 the subdorsal truncated-wedge shapes were of deep ochreous and 

 largely developed ; the inflated subspiracular region, belly and ventral 

 prolegs, of deep ochreous or buff colour, the latter tipped with 

 red ; a pear-shaped blotch of dark olive dotted with white 

 was situated below the subspiracular region on each segment ; 

 the anterior legs red. Harrison notes (Ent. Rec, ix., p. 293) : 

 " The changes in colour that many larvae undergo in the final stadium 

 are as follows — The red dorsal stripe turns yellow, then black ; 

 the subdorsal and supraspiracular spots undergoing the same 

 changes in turn. Then the caudal horn, head and legs, become 

 blackened (without, however, turning yellow). In the very black 

 forms, the supraspiracular spots almost cease to exist, and the 

 subdorsal are only visible because of their brighter surface. About 

 seventy larvae underwent the above changes, and these must have 

 been quite normal, and not due to disease, for the larvae continued 

 to eat most ravenously, and out of about eighty larvae, which did 

 not go down at once, only five were lost." Reaumur notes ( Me/noires, 

 i., pp. 289-291) that, when the larva is young or has just changed 

 its skin, its colours are more delicate than at other periods, and 

 immediately after a moult there is less black, whilst a delicate 

 green tint, with some little yellow, prevails. Later, when the colours 

 are fixed, it is blacker ; it also has yellow where it will be red, 

 and white where it will be yellow when the larva is more mature, 

 the yellow becoming first tinged with red, and then red, and the 

 white takes a yellow tint and then becomes yellow. There are 

 larvae that have only the little dots yellow, all the larger ones being 

 red — either rose-coloured or of some deeper tint. When about to 

 pupate the larvae change colour, becoming dirty brown and having only 

 some whitish spots. Weismann says (Studies in the Theory of Descent, 

 pp. 206-207) : "In the last stage the dorsal line is sometimes black 

 and sometimes red, or, again, this colour interrupted with black, 

 so that only small red spots mark its course. The head may be 

 entirely red, or this colour mixed with black. On the underside 



