(5) 



fnpa : tongiie-slieatli free and recurved in Hersc, free and not recnrved in 

 Coeloniu, not free in Aclicrontiu, alwaj's reaching to end of wing-cases. The jnipa 

 of Megiicorma is not known, bnt has doubtless a free tongne-case. 



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



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

 it is closelj' connected through Coelonia and Xanthopan. The relationship 

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

 never been noticed before. Ackerontia occupies in the classification of all authors 

 quite an isolated position. ITerse and Coelonia have been considered generically 

 identical either with Protoparce or with Ili/loicus, and tlie Sphinx here called 

 Megucorma as a near ally of the common Oriental mencphron, standing in Kirby's 

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

 question, we were struck by the great similarity between Ackerontia and (he 

 Aethiopian Sphinx described as Protoparce fub:inotata, named below Coelonia. 

 In fact, Ackerontia 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 has in hoih Ackerontia and ('oc^o/z/Vf the well-known tuberculated --shaped 

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

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

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

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

 above) is indicated rndimentarily. And the relationship of Xantkopan with 

 other genera of Spkingicae, e.g. with Panogena and Cocytius, is unmistakable. 

 We have, therefore, a gradation from the Spkingicae through Xanthopan and 

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

 of this series. Herse (convolridi, cingulata, etc.) is an offshoot from this branch, 

 and so is Megacorma, both of which agree with the other two genera of Ackeroiitiicae 

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

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

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

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

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

 among the lower Spkingicae, from which the Ackerontiicae are derived, a similar 

 structure of the larva occurs. 



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

 character which does not occur again among the Spkingidae asemanopkorae, while 

 it is found in many Old- World sj)ecies of Spkingidae semanophorae belonging 

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

 in the ])resent family, and shows at what peculiar results a classifier will arrive 

 wiio liases his judgment on one organ only. Ackerontia is another instance : here 

 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 Tkeretra. 



Keys to the genera : 



A. Imago. 



a. Tongue shorter tlian tlie thorax, the latter above 



with sknll-mark III. Arkeronti'i. 



Tongue longer than the body, (liora\ wilhoiit skiill- 



'uark ........./;. 



