1890 .] 
105 
[Packard 
Thus so far as the eighth uromeral dorsal spine is concerned, the 
Sphingidse may have descended as well from some Notodontians, 
or from Endromis, as from the Ceratocampidse. But the origin of 
the Sphingidse from forms like our modern Ceratocampidse is sup- 
ported by a fact not mentioned by other observers, i. e., the simi- 
larity in shape and the great size of the anal legs of Sphingidse 
and those of the Ceratocampidse. Any one who will compare the 
larvse of the two groups will be struck with the resemblances. The 
sphinx-like attitude is also assumed by Eacles imperialis while feed- 
ing ; and taking together this identity in attitude, the presence of 
a caudal horn, and the general shape of the body, I do not see why 
the Ceratocampidse may not be regarded as an archaic group from 
which the Sphingidse may have sprung, while the former may have 
originated from spined Notodontian larvse, such as CEclemasia con - 
cinna , the Notodontians being apparently the most generalized 
forms of all the Bomb3 T ees, and also, as regards the larvse, being the 
most plastic forms ; either assuming the greatest variety of ornamen- 
tation, or being quite unadorned. 
It is possible that the enlarged anal legs of Attacidse and of 
Sphingidse may be correlated with their habit of raising the anterior 
part of the body in a Sphinx-like attitude, the hypertrophy of the 
legs being due to the increased strain on the muscles of the legs 
in question. 
Agliatau is interesting from the fact that born with Ceratocam- 
pid features, retaining its great caudal spine, and those on the pro- 
and metatlioracic segments until the third stage, it then after the 
last' moult loses its characteristic spines, and becomes a smooth- 
bodied, thick larva, like an ordinary Attacine larva, but without 
any tubercles at all. The imago is in venation and general appear- 
ance a true Attacine moth. There is thus a great acceleration in 
its larval development, and a precocious assumption of Attacine 
features, though born a genuine Ceratocampid. This tends to prove 
that the two groups are only subfamilies. 
Vir. NOTE ON THE SURANAL, PARANAL PLATES, AND PARANAL FORKS OF 
VARIOUS BOMBYCINE AND GEOMETRID LARVAE. 
The supraanal or sur anal plate . — This plate, the podex of Kir- 
by and Spence, in Bombycine and Geometrid larvse, both as to its 
shape and ornamentation affords excellent characters for distin- 
guishing species, and we have found it of great use especially in 
