(O 



Pnjia : tongne-sheatli free and recurved in Ilerse, free and not recnrved in 

 Coelonia, not free in Acherontia, always reaching to end of wing-cases. The pnpa 

 of ^feg<l('Ol^ma is not known, but has doubtless a free tongue-case. 



Ilfi//. Cosmopolitan; one species in America and ten in the Eastern Hemisphere. 



This small tribe is a derivation from the following one, with which 

 it is closely connected through Coelonia and Xa?if/wpan. The relationship 

 between Acherontia and the genera with which it is here united to one group has 

 never been noticed before. Acherontia occuiiies in the classification of all authors 

 (juite an isolated position. Ilerse and Coelonia have been considered generically 

 identical either with Frotoparce or with TLjloicus, and the Sphinx here called 

 Megacorma as a near ally of the common Oriental menephron, standing in Kirby's 

 catalogue under Meganoton. When studying the structure of the species in 

 question, we were struck by the great similarity between Acherontia and the 

 Aethiopiau Sphinx described as Protopnrce fuh-inotata, named below Coelonia. 

 In fact, Acherontia is nothing else but a derivation from Coelonia ; it is a 

 Coelonia with a short and stout tongue. This conclusion, derived from the 

 com])arison of the structure and of the wing-pattern, is born out by the caterpillar, 

 which lias in both Acherontia and Coelonia the well-known tuberculated --shaped 

 liorn. Now, Coelonia shows close affinities in the pattern and structure of the 

 imago with Xanthopan—aud we have no doubt also in the caterpillar, which, 

 however, is not yet known of Xanthopan, — a genus of Sphingicae in which even 

 the peculiar structure of the inner surface of the second palpal segment (described 

 alxive) is indicated rudimentarily. And the relationship of Xanthopan with 

 other genera of Sphingicae, e.g. with Fanogena, and Coci/titis, is unmistakable. 

 We have, therefore, a gradation from tlie Spldngicae through Xanthopan and 

 Coelonia to Acherontia, the Death-head Moths being the most highly specialised 

 of this series. Herse (convohuli, ciiigulata, etc.) is an offshoot from this branch, 

 and so is Megacorma,\ioih of which agree with the other two genera of Acheron tiicae 

 closely in the specialisation of the second palpal segment. In Heise and 

 Acherontia a further specialisation obtains, which is largely observed again among 

 tlie Sphingicae, namely, the reduction of the pulvillus of the tarsal claw-segment. 

 The paronychia, too, lose their ventral and long lateral flaps in Acherontia. The 

 humped thorax of the larva of Coelonia is very significant. We shall see that 

 among the lower Sphingicae, from which the Acherontiicae are derived, a similar 

 structure of the larva occurs. 



The cavity at the end of the first palpal segment of Megacorma is a singular 

 character which does not occur again among the Sphingidae asemanophorae, wliile 

 it is found in many Old-World species of Sphingidae semanophorae belonging 

 to Theretra and allied genera. Such parallel development is met with everywhere 

 in tlie present family, and shows at what peculiar results a classifier will arrive 

 who bases his judgment on one organ only. Acherontia is another instance : liere 

 the palpi do not touch one another, and therefore do not conceal the base of the 

 tongue ; the same is the case in several genera related to Theretra. 



Keys to the genera : 



A. Imago. 



a. Tongue shorter than the tliorax, the latter above 



with skull-mark III. Acheronti'i. 



Tongue longer than tlie body, thorax witliout skull- 

 mark ......... b. 



