228 BRITISH LEPIDOPTERA. 



of the larva, red generally predominates, but, in some specimens, 

 this is replaced by black. The ground-colour is also variable, 

 being generally a shining brownish-black, but sometimes dull coal- 

 black. The shagreen dots are sometimes white and sometimes 

 yellow, and the "mirrors" of the ringspots are also often yellowish. 

 In many specimens from Kaiserstuhl, the red was unusually vivid, 

 and was not limited to the ordinary places, but occupied also the 

 triangles on the posterior edges of the segments (fig. 44). which 

 are green in the 3rd and 4th stages (fig. 42). This form has also 

 been figured by Hubner. In one individual (fig. 43) the under 

 ringspots were wanting, whilst the upper ones possessed a beautiful 

 red nucleus, fading away anteriorly and showing the first step in 

 the formation of a complete eyespot." Caradja's observation that, 

 in Roumania, the summer larvae are of light colour, but those 

 which appear in autumn always extraordinarily dark, is interesting. 

 In opposition to the usually accepted view, the same author makes 

 the noteworthy observation that the lightest larvae mostly produced 

 darker, often red-tinted, moths, the darkest always light specimens 

 only. Bartel notes (Pal. Gross-Sc/iuielt., ii., p. 80) that, " in Sicily, 

 the larva? of this species are of a brighter green colour than in Central 

 Europe. The black colour which, in general, characterises the full- 

 grown larvae of the latter locality, disappears almost entirely. The 

 large yellow spots on the sides are filled in with white, and the 

 yellow line over the legs is unicolorous and entirely without admixture 

 of red. In Spain and other localities of southern Europe (also in 

 western Asia and in Algeria) almost entirely bright yellow coloured 

 larvae occur ; the head of these is red, but they produce only the 

 ordinary form of the moth. Larvae from the eastern Pyrenees form 

 in their markings a transition from the ordinary D. euphorbiae larvae 

 to those of D. nicaea" Lederer records larvae from Amasia and Tokat 

 as being exceptionally pale. Eaton observes that the adolescent larvae, 

 exceedingly abundant at Biskra, do not present any variation in 

 colour, only that some have the dorsal line red, others yellow. 

 Sich says that the larvae become somewhat duller when fullfed 

 and at the time that they are wandering about for a place for 

 pupation. 



Development of larval markings. — First instar : The young 

 larvae (Studies in Theory of Descent, pi. v., fig. 37), immediately 

 after hatching, measure 4mm. ; they are at first rather light, but, 

 in the course of half-an-hour, they are seen by the naked eye to 

 become of a deep velvety-black j later, on increasing in size, they 

 again become paler, appearing of a greenish-black, and subsequently 

 blackish-green. On further increasing in size (fig. 38) they are 

 blackish-green, with the horn, head, legs, and a crescent-shaped 

 chitinous plate on the back of the prothorax black. There are 

 also, on the last segment, a double and two single black chitinous 

 plates. Of the later marking of the caterpillar there is scarcely 

 anything present. The spiracles appear as white spots, and, on 

 each segment, there are a number (usually 10) of small warts, 

 each of which emits a single bristle. When the young larva 1 have 

 attained a length of 7mm. (hey are olive-green, and do not contrast 

 so brilliantly with the green of the Euphorbia leaves as before, 

 neither do they as yet possess any markings. Second instar : The 



