12 
ME3I0IES OF THE is^ATIOXAL ACADEMY OF SCIEiTCES. 
Of the great group of GeometridiB many kinds are arboreal (Dendrogeometrids), and in 
sucli cases are almost invariably tuberciilated in manifold ways. We know of no liairy or tufted 
caterpillars of this group or of any family below tbeiUj with the exception of the Pterophoridie, 
The arboreal Pyralidie, Tortricid:e, and Tineida* live in such concealment, between leaves, or 
in buds, or as miners, that they differ little in their surroundings from the low-feeding forms, and 
are thus scarcely ever tubercidated or spiny; in fact, we can not recall one of these groups which 
are s^. The Pterophoruhe are, to be sure, spiny, but they are low feeders, and their peculiar 
excretory setai (the Driiseuharcheu or giandular hairs of Zeller^) are similar, as Diminock has 
observed, to the glandular or long hairs of plants; Miss Murtfeldt adding that “there is a very 
close imitation in the dermal clothing of the larvie [of LeioptUus Hericidactylus] to that of the young 
leaves of Veruoiiia, on which the spring and early summer broods feed.” (Psyche iii, 390, 1882.) 
Eeturning to the Bombyces, all the IS'otodoutians, without any exception, known to us have 
trees as their principal, if not exclusive, food plants. Thus, of the 37 species of this group whose 
larval forms ai'e known, and whicli are enumerated in Mr. H. Edwards’s “Bibliographical catalogue 
of the described transformations of North American Lepidoptera,” together with an additional 
species (lehtJujura sirigosa) omitted from the catalogue, all are known to feed on trees, unless we 
except Datana mojor^ which feeds on Andromeda. It is noteworthy that the only si)ecies found 
thus fill' on a herbaceous plant is the caterpillar of Apatelodes torrefacta^ which Harris found 
on the burdock, though usually it is an arboreal insect. This apparently omnivorous feeder 
resembles the species of Halesidota, all of which occur more commonly on trees than on herbs, 
and thus differs markedly from the majority of the Lithosiaus and Arctians, unless we except 
the Nolidte, Now the larva of Apatelodes is hairy, the long, white hairs having scattered among 
them black ones, with more or less black pencils, thus resembling the peculiar yellowish or white 
caterpillars of Halesidota, with their black tufts and i^eucils. Similar forms are some of the 
arboreal, hairy Noctuidm, as Gharaclra deridem. It seems evident that the resemblance to each 
other in such different groups is the result simply of adaptation, brought about by two factors, 
the i)rimary one being a change from a low- feeding to an arboreal station, and consequent isolation 
or segregation, and the secondary one being natural selection, the latter farther tending to pre- 
serve the specific form. 
It will be seen b}’’ the following review that the North American Bombyces in general, with 
the excexition of the Aixtians and Litliosiaus, live on trees, and this will in general apply to the 
Old World species. In the group of Lasiocampuhe, represented by Tolype,' Artace, Heterocampa, 
Gastropacha, and Clisiocampa, the station is an arboreal one, none being known to feed on 
herbaceous idants. x\ll the Geratocamx>idie, all the neniileucidm and Attaci, the Platyptericidiu,- 
all the Cochliopodidic (Limacodes), including both the naked and spiny genera, as well as the 
Psychidic, live exclusively on trees. Of our North American Liparidie, all are arboreal in station, 
except the Galiforniau Orgyia vetustay which lives on the luijiue. Finally we come to the Arctians- 
and Lithosiaus, whose hairy, or rather setose, larvm in general feed on herbaceous plants and 
sometimes on trees, being in many cases omnivorous, wliile those of the Nolidm and Nycteolidm 
whose history is known, are arboreal. 
Of the Zygicnidm, including the Gteuuchida}, the sx)ecies are low feeders, living on lichens, - 
grasses, and other low plants, or upon vines. The Dioptid genus Phryganidia feeds on the oak. 
Of the Agaristidm, some are low feeders, EiiSGirrliopteriis gloveri feeding on Portulaca, while the 
majority prefer vines (Vitis, etc.). As to the boring habits. of the Hepialidm and Cossidm, which 
we now consider as independent groups, related to the Tineina, rather than belonging to the 
superfamily Bombyces, these seem to be the result of early adaptation. 
An examination of the food plants of the British species of Bombyces, taken from Stainton’s- 
Manual of British butterflies and moths (1857), gives the same results for the Old World, as will 
be seen by the following statements: 
that mauy moths, Notoilontiaus among them, Trhich in the Northern States feed on trees alone, in the Gulf States^ 
according to Abbott, feed on shrubs, vines, and low plants, as well as trees. 
In rei>ly to an inquiry, Mr. W. H. Edwards kindly writes me: ‘‘1 do not think that the butterfly larvte which, 
live on trees are under more favorable conditions than low feeders as to healthiness or ease of rearing/’ 
^Revision der Pterophorideu. Liuniea entom., 1852, vi, 358. Mentioned by Diminock. 
