234 BRITISH LEPIDOPTERA. 



of the same pattern but slighter, and other Sphingid cocoons 

 are also of the same pattern. Pupa. — The rough-skinned pupa 

 suggests those of the Smerinthids as much as those of the 

 Saturniids, although structurally nearer the latter. We may 

 here note that the pupa of Dimorpha versicolora appears to be an ex- 

 ception to Chapman's general definition of the pupae-obtectae, that, as 

 pupae, they " have no power to emerge from the cocoon or to 

 progress in any way," for the pupa of this species systematically 

 forces itself out of the cocoon before the imago emerges, and, as 

 a pupa, therefore, it comes, as regards this particular character only, 

 under Chapman's division Incompletae. 



We are not inclined to follow Kirby in going back to 

 Schrank's grouping and in considering Hiibner's stirps Dimorphae 

 (as represented by Dimorpha versicolora) simply a genus of 

 Bombyeidae, which he defines {Handbook, &c, iv. p. 61) as 

 having : " The frenulum absent ; the mouthparts rudimentary, the 

 antennae pectinated in both sexes ; the wings broad ; the body 

 generally stout ; the hind tibiae armed with two small spurs ; the 

 larva naked, with a fleshy horn on the back as in the Sphingidae ; 

 the pupa enclosed in a cocoon." Grote writes {Die Satumiiden, p. 

 5) : " The larva ot Dimorpha in the first stadium strikingly resembles 

 the larvae of the Lachneids. The primitive original stadium is 

 wanting. Segments two and three each bear two warts above the stigma. 

 The tubercles are throughout of the form of warts. On the abdominal 

 segments iv and v are separated, on the other hand the presence of 

 the subprimary tubercle vi cannot, with certainty, be made out 

 {cfr., fig. 3). The entire blackish-coloured and bristly creature forms 

 in its first skin a sharp contrast with the naked-green skin of the 

 later stages. The accompanying figure is from a microscopic 

 drawing by Dyar, to whom I sent the larvae in question. The 

 seta marked vi (?) stands too low down to be referred with certainty 

 to the subprimary, particularly one might assume that this seta would 

 have to be referred to vii, especially since the light-coloured wart 

 also is here wanting." 



We may here note that Hermann {teste Standfuss) obtained 

 pairings between Dimorpha versicolora $ and Aglia tau % , but 

 the eggs were infertile. Standfuss records {Handbook, pp. 124, 

 125) an experiment on pupae of this and other species that 

 appears to show that a hurrying of the pupal stage tends to produce 

 less well-marked specimens. He says that out of a large number 

 of pupae of Dimorpha versicolora, Satitrnia pavonia and Aglia tau, 

 he had a few emergences of imagines without previous hybernation 

 of the pupa. The aspect of the individuals belonging to the first two 

 species was markedly altered in the direction of decidedly weakened 

 and less distinct markings. He further notes that large numbers of 

 pupae of Saturnia (in these cases from 200-400 specimens were used) 

 were kept very dry for 7-10 weeks, from June to the end of 

 September. They were then freely and repeatedly moistened, and 

 about 1 per cent, of the moths emerged from these pupae 10-20 days 

 after the damping. The fully-developed moths mostly show a de- 

 parture from the ordinary form of the species, the elements of the 

 pattern being less sharply outlined, more or less washed-out and 

 confused, and the repetition of the experiment shows that this cannot 

 be merely a matter of chance. 



