MEMi^IRS OF THE KATTO:NrAL ACADEMY OF SCIEl^CES. 
29 
tlie larval foriaSj especially of tiie earliest stages, it is not diflicult to construct a genealogical 
tree of tlie subfamilies Heterocampiua^ and Ceruriiue. When t.aking into account the larval stages 
of the entire family, even Avith our present imperfect knowledge, it is easy to see that Datana 
stands at the base, is the more generalized i>rimitive form, and was perhaps the lirst to diverge 
from the stem-form of tlie family. 
The first mrthor to call attention and at the same time to treat in a philosophic way of Avhat 
he has called “the incongruence of form relationship, between larvicon the one hand and imagines 
on the other” is Weismanu, in his well-knoAvn Avork entitled Studies in the Theory of Descent. In 
Chapter II of the second Amlume, entitled “Does the form relationship of the larva coincide Avith 
that of the imago?” he iioints out certain incongruences between the larAml and adult characters. 
He claims that “neither the group of jVlicrolepidoi^tera nor those of the ^octuina,, Bomhycina^ 
Sphiiujinn., and Rhopalovera can be based systematically on larval characters,” adding the quali- 
fication, “ScA^eral of these groups are indeed but indistinctly defined, and even the imagines 
present no common characteristics by which the group can be sharply distinguished,” Within the 
families, however, he states; “There there can be no doubt that in an overwhelmingly large 
majority of cases tlie phyletic development has 2Aroceeded with very close i^arallelisin in both 
stages; larval and imagiual families agree almost completely. On the other hand, “in the butter- 
flies a perfect congruence of form relationship does not exist, inasmuch as the imagined constitute 
one hu’ge group of the higher order, Avhilst the larvie can only be formed iiito families.” But in 
this case Weismann does not seem to be aware that the imagiual Rhopalocera as such is quite an 
artificial group, and that the imagiual flxmilies recognized by Bates, Scudder, and others have 
imrhapsmore equivalent, congruent, or nondivergent larval forms than his remarks would seem to 
imply. 
But without attempting to enter into an exposition or criticism of Weismann’s general 
statements, liis whole discussion being most suggestive and stimulating, we will turn to Avhat he 
says of the NotodonthL'C : 
An especially striking case of incongruence is offered by the family Kotodonitda'f under which Boisduval, 
depending only on imagiual characters, united genera of which the larvtO differed to a very great extent. » * * 
In fact, in the whole order Lepidoi)tera there can scarcely he found associated together such diverse larva3 as are here 
jdacod in one imago family. 
He then refers to the short cylindrical cateiqAillars of Cnethocampa^ Avhich, hoAvever is not a 
lilotodontiau, but a Lasiocampid, lie then briefly refers to the larvm of Ilarpyia (Cerura) and the 
caterpillars of Staiiropns, Hybocampa, and Notodonta. Without giving further attention to the 
family, he returns to the butterflies. This family, then, presenting “an especially striking case of 
incongruence,” Ave will briefiy discuss, referring the reader for fuller details to the figures on the 
plates. 
In the first place, as a matter of fact, the more one becomes familiar with the Lepidoptera 
and their larval forins the easier it is to distinguish the larA’oe by their “family” characteristics, 
I)remising, hoAvever, that the term family is of Awy nneertain meaning, and that different 
authors differ as to what to call a family as much as they do Avhat to designate a species. But 
no one, Ave think, need to err in correctly picking out or identifying any Bombycine larva excefit, 
perhaps, a few Notodont laiwm, which are liable to be confounded Avith certain Thyatiridm, and 
the hairy Xoctuidic, but even then a careful exaniinatiou Avill show family differences CA'cn Avhen 
adaptation and modification have nearly bridged over the lundamental differential characters. 
In this Avork I have divided the family into seven groui)S, which may be for conA^enieuce 
regarded as so many subfamilies. I was first led to do so by the larval characters alone, but 
found that this clasvsificatioii Avould also apjfly in general to the moths, so that there jiiwed not 
to be so much incongruity as Avas expected. There appear to be, -then, seven larval subfamilies 
and seven imagiual subfamilies. Others may not agree AAuth this vieA\', but it is the most rational 
classification I huA^e been able to make. 
Beginning Avith tlie most simple forms of larva, those of the Olnphimnw^ AA'liich, both as 
regards those of the Old and New World, are tolerably constant, the adults certainly differ notably 
from those of other subfamilies, as also do the lars^ie and pupie. 
