360 BRITISH LEPIDOPTERA. 



generalised in structure and position as have the Sphingids. Neither 

 has the imago of Aglia a frenulum, nor tongue, nor two anal nervures 

 to the hindwings, all of which characters mast have been present in 

 the ancestral Sphingid. The Sphingid branch, therefore, left the 

 main Sphingo-Micropterygid stirps ' quite separately trom either that 

 of the Dimorphids or Attacids and not through them. We have 

 already presented this view of the subject (anted, vol. i., pp. 

 124 — 126). 



Poulton published (Trans. Ent. Soc. London, 1888, pp. 555 

 et sea.) in detail the ontogeny of Aglia tan and discussed its affinities. 

 He also considered the structure of various Sphingid larvae and 

 finally concluded that "the Sphingids are a specialisation of the 

 group of Saturnian-Bombyces, and that the following order represents 

 the nearest affinity and is an approach towards the expression of 

 genetic relationship : Sphinx, Acherontia. Smerinthus, Ceratomia, 

 Lophostethns, Aglia, Ceratocampa (Attacns), SaturniaP He then 

 adds "The other genera of Sphingidae will precede Sphinx as in the 



usual arrangement Endromis and Bom by x mo?H will 



also be included in some of the gaps in the above mentioned list, 



but their exact position is uncertain The imaginal 



condition of the Sphingidae which comes nearest to Aglia, &c, 

 is strongly in favour of the above arrangement. They alone do not 

 feed in the perfect state, and do not fly in the characteristic manner 

 of other hawk-moths ; in the strict sense of the word they are not 

 hawk-moths. Their mode of flight and especially their rudimentary 

 and unused mouth-parts, are further points of affinity to the 

 Saturnians." 



We need not say that we disagree almost wholly with these 

 conclusions. If anything is clear in the phylogeny of the Sphingids, 

 it is that no one of the genera mentioned above has been derived 

 through any other one. It is equally certain that neither Dimorpha 

 (Endromis) nor Bombyx (niori) could fill up any conceivable gap in 

 the series mentioned, both forms being, in one or more aspects, 

 more generalised than any one of those mentioned. It is also 

 certain that the Amorphid branch* has evolved within the Sphingid 

 stirps from a tongued ancestor, and that its tongueless condition 

 is quite independent of the parallel condition found in the Attacids. 

 Their slower mode of flight is possibly even a specialised (and 

 not ancestral) trait, and consequent on the loss of the frenulum. 

 Our treatment of the various subfamilies will possibly afford further 

 critical differences from the conclusions arrived at by Poulton. 



His detailed facts, however, must be referred to by every student. 

 We can only mention a few points. His summary of the resemblances f 

 between the larva of Aglia tau and those of the Sphingids, in general, 

 is as follows : 



(1) Caudal horn : Changes o\' si/.e during growth ; 2 terminal bristles ; bi- 

 furcation ; longest and movable in early stages ; colour, and white zone ; thorn-like 



* This, we suspect, is the branch that Poulton intends by " The imaginal con- 

 dition of the Sphingidae which comes nearest 10 Aglia." 



t Many of these characters, e.g., attitude, shagreen hairs, oblique stripes, are 

 spread over groups as separate as Lachneids, Dimorphids, Bombycids (Bombyx 

 mori), and Attacids, whilst shagreen hairs occur in some butterfly larva?, and 

 oblique stripes and a caudal horn in the Notodontids, where they cannot indicate 

 alliance (Bacot). 



