MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 35 



•'The most nsitiinil iirratiutMiiiMit would be for tlic Sphiuj-ida' to form the end of one special 

 line of Bombyce.s. the order being tiie exact reversal of that j;i\en above" (p. 578). 



In an essay" published in 1890, I indorsed Poulton's conclusions, remarkini;- that while the 

 Sphingidiv had probably descended from forms iiUe the more generalized Ceralocampida\ there 

 were some points in the imaginal characters which ajjpeared to forbid the idea that the}' have 

 immediately descended from Aglia. It now appears that this genus does not stand alone, but is 

 closely related to Arsenura, etc.. the group Agliiiuc licing a South American one, with a single 

 Eurasian genus in the Arctogicic realm. I may 1)C permitted to (piote the view then presented. 



''But the origin of tiie Sphingidre from forms like our modern CeratocampidiB is supported 

 by a fact not nuMitioned by other observers, i. e., the similarity in shape and tlic great size of the 

 anal legs of Sphingid;e and those of the Ceratocampidw. 



"Anyone who will comi)are the larviB of the two groups will be struck with the resemblance. 

 The sphinx-like attitude is also assumed by Eaclex iiiiperlaJix while feeding, and, taking together 

 this ideutit}- in attitude, the presence of a caudal horn and the general shape of the body, I do 

 not see why the Ceratocampida? may not be regarded as an archaic group from which the Sphing- 

 id;¥ may have sprung, while the former may have originated from spined Notodontian larvfe, 

 such as (Edenuisla cv/icuuiu, the Notodontians being apparently the most generalized forms of 

 all the Bombyces, and also as regards the larva?, being the most plastic forms; either assuming 

 the greatest variety of ornamentation, or lacing (piitc unadorned." 



In his excellent monograph of the Sphingidie of America north of Mexico'-' Prof. J. B. Smith 

 divides the family into four groups or subfamilies: Macroglossinaj, Chserocampinse, Sphinginw, 

 and Smerinthina'. in the descending order, regarding with others the Macroglossiniv as the most 

 specialized group, and the Smerinthinii? as standing at the foot of the series, having a "small 

 retractile head and obsolete tongue." He considers them as " insects thoroughly bombyciform 

 in habit and appearance, but completely sphingiform in larval and imaginal character." He also 

 briedy suggests more clearly than any previous author, though not in a detailed way, the 

 resemblance of the Smerinthina^ to what he calls the Saturniidaj, stating that the group'Sme- 

 rinthina- "seems to lind closer allies in the Saturniidse througli Cressoiiia to the most typical 

 Smerinthina?." 



I have, after a somewhat prolonged study of the Ceratocampidse, compared them with the 

 genera Cressonia, 'Marumba. and Paonias, and have been greatly interested and surprised to find so 

 many vestigial ceratocampid characters in the larva, pupa, and imago of the Smerinthina^. The 

 result is to prove, at least to my own satisfaction, that the caudal horn is only one of a numlier 

 of characters which indicate the direct descent of the Sphingid;e from the Ceratocampida\ and 

 most probaldy from the most primitive subfamily, the Ceratocampina?. 



The two diagnostic characters which separate the more primitive and generalized Sphingidse 

 from the Ceratocampida? are the position of the tubercle of the spiracular series, or /• of Dyar, in 

 the larva, and the presence of an additional vein (III 2, radius 2) in the forewings of the imago. 

 As stated fuither on, these appear to be sudden acquisitions which originated during the period 

 when the group diverged from the parent ceratocampid stock. It should be observed that the 

 tubercle /• is of the same shape and structure, the ditierence t)etween the larva? of the two families 

 being in regard to its position. 



Lai'i'dl fe<iturt>i. — We will now, beginning with the larval characters, give the grounds for 

 our opinion that the Sphingida^ have directh' descended fi'om the Ceratocampiufe. 



The young larva (Stage I, PI. XLII) of Ceratoniia amyntor, in the shape of the head and pro- 

 portions of the body, the shape of the suranal plate and anal legs, is the same as in the V'oung 

 of Eddes inqyerluVifi. 1 can see no distinctive family characters in the parts of the head and organs 

 of mastication, in the shape of the two divisions of the clvpeus; that of the cleft labrum and of 

 the antennie are nearly identical in Eacles and Ceratomia. It is doubtful whether there are diag- 

 nostic primary family features in the head and mouth parts of lepidopterous larvfe in general, 



«Xotes on come points in the external structure and phylageny of lepidopterous larvfe. Proc. Boston Society 

 Xat. Hist. XXV. May, 1890, p. 100. 

 '' Trans. Amer. Ent. Soc. XV, 1888. 



