30 
MEMOIES OF THE XATIONAL ACADEMY OF SCIENCES. 
Tlie reiuarkabl}’' woolly and j^euciled larvae of Apatelodes are congruous with the very distinct 
imagines of the subfamily Ajjatelodlnw, which are so well dehned by their structural characters. 
The hairy and brightly banded larvm of the Fygwrina^ so unlike those of other Yotodontians, 
are paralleled by the general appearance and structure of the mothSj so much so that the group Avas 
regarded as a distinct family (Pygieridje) by Duponchel. The larvie of the European Pygjeriuie 
are hairy and gaily striped, and related in much the same way to our larval Dataiia as the imago 
is to our iinaginal Datana. 
The larvic of the subfamily Icldltyurina\ represented by only a single genus, need not be 
confounded with those of any other division of the family, though there is a great deal of idasticity 
Avithiii the limits of the group. The most generalized species is the larva of J. (tpicalis [van) and 
its allies hrncei since it has no large sx^ecialized tubei^cles like those of Uiclusa and 
alhomjma^ and the latter species differs, both as regards larva and imago, from T, indusa. The 
incongruence in this group is not greatly emphasized. 
But in the. two next subfamilies there is a striking lack of congruity between the larva and 
moth, both in the genera an<l si)ecies. 
Among the Xotodoutiua^ we have Uyparpax, Avliose imago is so different, in the shape of the 
wings and in the color of the body and wings, compared with any other genus of the group or 
even of the family; yet the larva is very nearly allied to those of Xylinodes and of Scliizxira, 
A remarkable case of incongruence is the larva of Sehiziira concmna. This well-known 
caterpillar, with its formidable armature of long hobnail like sinnes and its gay head and swollen 
coral-red dorsal humx>, would seem to be the tyi)e of a distinct genus, and yet from a study of its 
adult character it is not sei)arable from the other species of Schizura, and we have dropx)ed the 
genus (Edemasia we originally proposed for it from the lack of stable differential characters. 
The freshly hatched larvte, howeA’cr, is undistinguishable from that of other Schizune yet known, 
and x^orhax)S we have done violence to the x^rinciples of classification in not alloAving it to remain 
in the genus we originally x>roposed for it. At all events, it with other Schizune evidently had a 
common parentage, and it has diverged since it first molt farther away from the stem than others 
of its cosi)ecies and maybe regarded as an incipient genus. It is also x)laiu that the causes which 
have acted upon this organism have from the first been of a quite different nature from those which 
have been efficient in causing fixed variations in other directions, resulting in the fixation of the 
other species of the genus. As the change takes ifface after the first molt, this may have been 
produced in the Tertiary x^eriod. Its larval stages are discussed at some length under the head ot* 
the species in the systematic x^ortion of this work. 
On the other hand, in the genus Seirodonta we have a remarkable case of congruence in its 
larva as compared Avith that of Heterocamjut manteo. It is almost imi^ossible until after repeated 
and careful comparisons to distingush the caterpillars of Seirodonta hiUneaia and R, manteo, though 
the imagines differ somewhat, x^erhaps generically. At times I have united Seirodanta with 
Heterocampa^ but for the x^resent conclude to keep them ax^art, as others have done, but really the 
genus is not so “good” a one as CEdemasia.* 
In the genus Reterocampa, as the name implies, there is a remarkable degree of diversity 
between the cateri^illars of the different species, and our knoAvledge of them, esx^ecially of their 
early stages, has greatly extended since the days of Doubleday. 
If we take account of the fully groAvn caterpillars, it seems (]uite evident that there are several, 
perhaps three, “larval” genera in the group. In R. manteo, (juttivitta, Mundata, ohliqna, and astarte, 
the body in the fully grown larva is smooth and unarmed, but in p/drcreu., Avhich has a x>air of 
small tubercles on the x>rothoracic segment, we have a notable persistance of early larval features. 
Unfortunately Ave are not yet familiar with the earl^-- stages of this caterpillar. Possibly this 
species is the stem form of the groiq). 
In R. ^mieolor Ave have a transfer of the differential generic characters from the x)rothoracic 
region to the anal legs. Though the high x>i'othoracic tubercle appears in the first stages and 
perhaps, as in Macrnroca^njya, in all except the last stage, when the larAur is on a level with the fully 
' I have some sketches made by Mr. Bridgham of a larva in its first three stages -which is Schizura-like, and as 
it feeds on the elm it is iirobably Seirodonta. Should it prove to be such, this genus is a Schizura in the early stages 
and a Heterocampa in the last. 
