370 BRITISH LEPIDOPTERA. 



Sharp observes (Insects, ii., p. 381) that " the Sphingid larvae 

 do not spin cocoons, but bury themselves in the earth," a general 

 statement by no means true of all the species. Many spin cocoons, 

 the Eumorphids and Sesiids often with a fair amount of silk, 

 and one suspects that this is the ancestral habit of the larvae of this 

 superfamily, and that the frequent absence of puparia in the Amorphids 

 (populi), although Mimas tiliae often uses quite a quantity of silk, and 

 the construction of earthen ones (Manducids and Sphingids) are 

 really signs of specialisation. 



We have already noted (anted, vol. ii., pp. 59 — 60) that the 

 characteristic markings of the larva may be seen upon the pupa 

 immediately after the skin of the former is thrown off, and that 

 these appearances may be fixed by placing the pupa in spirit, and 

 thus checking the darkening of the surface*, the persistence of 

 such colours depending upon the fact that the cells of the hypodermis 

 of the larva and pupa are the same, so that any pigment contained 

 in them during larval life may remain unchanged after the pupal 

 period has begun. Poulton figures (Morph. Lep. Pupa, p. 193, 

 fig. 2) a pupa of Sphinx ligustri in which the characteristic larval 

 markings are very plainly developed, and, in this, the purple borders 

 of the stripes bear a relation to the segments similar to that borne 

 during the larval stage, and this is especially well seen in the 



border of the last stripe The relation of the coloured 



borders to the spiracles is just the same as that of the larva. 

 Poulton adds that, " on removing a portion of the cuticle and 

 examining its under surface, it may at once be seen that the colour 

 of the border is due to the pigment in the adherent hypodermis 

 cells, which can be detached with loss of ihe colour. It is thus 

 certain that the constitution of the coloured stripes in the pupa 

 is similar to that in the larva, while the dark surface of the former 

 is entirely different, and due to a darkening of the cuticle." Similar 

 facts are true with regard to the newly-formed pupa of Acherontia 

 (Manduca) atropos, Smerinthus ( ' Amorpha) populi and S. ocellata (loc. 

 at, p. 194). 



The Sphingid pupae are large and robust, varying considerably, 

 however, in the density and character of the integument and in 

 the development of the various parts, so that it is not at all easy 

 to give any character that defines a Sphingid pupa from that of 

 other families, although one finds some characters that, when 

 present, are very distinctive, e.g., antennae, proboscis, lateral flanges, 

 &c. One observes the homologues of the anal claspers of the larva 

 usually to be traceable as two convex cushion-like structures on 

 either side of the anus, and, in some instances, these cushions retain 

 the general appearance of the larval structures (Poulton, Morph. 

 Lep. Pupa, pi. xx., figs. 8, 9, 10). The position of the larval prolegs 

 is usually represented by functionless scars upon the pupal cuticle, 

 and one can almost always trace in the Sphingid pupa a scar corres- 

 ponding with the larval caudal horn. Even in those species— Eumorp/ia 

 elpenor, Theretra ( Choerocampa) porcellus, <kc. — in which it is feebly 

 developed at the close of larval life, this scar is distinctly traceable, 



* Larvae of Sphingids can be well preserved in a saturated solution of alum 

 (Lovett). 



