36 MEMOIRS OF THE NATIONAL ACADEMY OF SCTENCE.S. 



■wliatovor m;iy be said of the sd'Oiidarv aniiaturc; at least we have not deserved any, certainlv 

 none of taxonoinic value. thoui;ii this subject has not yet l)een carefully or extensively examined. 

 The habits of nearly all lejjidopterous larva* beino- the same, we should not expect any decided 

 diti'erences'except in tlie leaf miners and the more primitive forms, such as Eriocephala (Monog'. 

 Bombycine ^Sloths, I. j). (JO). 



Tiie head in the Smerinthiniv uenera is conical, the vertex tending to be narrow and some- 

 what elevated. I)ut in the hiyher Sphinoidte the head ))ecomes round. Now, the conical shape of 

 the head of the Siucrinthin;v seems to have become directly inherited from the conical shape 

 characteristic of the Ceratocampidie, especially Adelocephala. the most primitive genus of the 

 grouj). 



In the armature the position of the setiferous tu])ercle /• directly in front of the spiracle is a 

 trenchant or diti'erential character, and, as Dyar says, it is characteristic of the sphingid larvse. 

 AVe are able to confirm all- he says as to this feature. As we have already stated (p. ;-!l). 

 the freshly hatched larva of Cemtomia amyntor al)solutely ditlers in this respect from any larvie 

 of the Saturniides. It should be observed, however, that these primary tubercles disappear after 

 the first molt and that only the freshly hatched young of Ceratomta ainy)it<>i\ and C iinduJom have 

 been examined. Provisionally, however — namely, so far as our'present knowledge extends — 1 

 quite agree with Doctor Dyar as to the significance and value of this group character. The posi- 

 tion of the tubercle in the Sphingida- is one apparently which was suddenly acquired, as if by a 

 leap, or "mutation, ".but as to the cause of the change of position, since in all the great groups 

 of bombycine moths (Saturniides) it is universally situated below the spiracle, while tubercle 

 'ir is moved up behind the spiracle — we are quite in the dark. 



The glandular seta? of Ceratomia are like those of certain Nott)d(intid;e. 



This is a primitive character, not occurring in Ceratocampida», in which the seta? are all 

 acute, nonglandular, or the setse at time of birth are, *with the tubercles, converted into large 

 spines. Another feature in smerinthine, but not the 'higher" sphingid larva?, is the occur- 

 rence of crowded miiuite secondary tubercles on the integument of the head and trunk, render- 

 ing the skin rugose or shagreened. An approach to this is. however, seen in larval Adelocephala 

 and Anisota. Also sphingid larvie have no specialized lateral or submedian spines on the sur- 

 anal plate, or rough, coarse granulations on the edge of the anal legs. It will be remembered 

 that the head in the smerinthine larvte is subconical. .narrowing above, while in the more special- 

 ized groups the head is more rounded. This conical shape of the head seems to have been 

 directly inherited from tbe Ceratocampida?. 



A salient feature of the Sphinx larva is the caudal horn: as has been shown b}' a number 

 of entomologists, and, as we have repeatedly observed, it ditlers in no respect in its general 

 shape and originally double origin from that of the Ceratocampidie, and seems to be, like the 

 other characters here mentioned, an heirloom from the Ceratocampida>. It appears, then, that, 

 with the exception of the position of the tubercles Iv and v, the larval characters of Sphingida? are 

 .such as indicate the direct descent by divergent and saltatory evolution of the group from some 

 primitive ceratocampine form, like Adelocephala. 



Inthe very interesting larva of the South African sphingid, IjijiJioKtefhiis dumolinii^ we have 

 the unique occurrence of a larva beset with a complete armature of long, rather stout, chitinous 

 spines, those of the dorsal and subdorsal series about or nearly as long as the median caudal 

 horn. Doctor Dyar" has thoroughly discussed the armature of this larva and shows that Mhile 

 it has a remai-kably ceratocampid-like appearance the tubercle >• is situated directly in front of 

 the spiracle, a charac,t(>risti<' of its position in those larva' of the sphingids yet known. There 

 are no spines on the first thoracic segment; tubercle // is not represented. The larva, he says, 

 "is a true Sphinx, not more nearly related to the Ceratocampids tiiaii any other Sphinx, since it 

 possesses true sphingid tul)ercles, iv above r and before the spirach'. not united with /• as in all 

 the Suturnian phylum. Functionally, indeed, it is a Saturnian like the African Saturnians, 

 with thorn-like tubcicles; but the character is evidently adaptational, an iri'egular hypertrophy 



«Proc. Eut. Sue, Washington, iv, May 13, lyOl, p. 440. 



