MEMOIES OF THE is^ATIOXAL ACADEMY OF SCIENCES, 
13 
Wolulw, — Of the 3 Britisli species, 2 feed on tlie oak and 1 on tlie liawtliorn and sloe. 
Lijparidw. — Of the 12 species, all feed on trees and shrubs, except Lcvlia ccoiosa, ^\diich lives on 
reeds and other water plants. It is tufted. 
Kotodonikhv, — Of 24 species, 1 ( DiJoha ewruleocepliala, which is smooth, with no protuberances) 
feeds on the hawthorn and other plants. 
Fkiti/pierwidw.—Of the 0 species, 5 feed on trees and 1 on a shrub. 
Endromidw. — The single sptcies is arboreal. 
Psychidw, — The 2 species, whose larval habits were known, feed on trees and shrubs. 
CochUopodida\ — The 2 species feed on trees. 
Saturniida\ — The single British species feeds on the heather, a shrubby plant. 
Lasiocampida\ — Of 11 species, 5 feed on trees, the others on shrubs and herbs. 
NocUio homhyces, — All the British species are reported as ‘‘living on trees and shrubs quite 
exposed.'^ 
Bomhycoid(i\ — All the species of Acronycta live on trees and shrubs. 
Inflxtence of a change from low to high feeding plants^ L e., from Uring on an herhaceons to an 
-arboreal ntation, — It appears, then, that the more typical Bombyces, such as the Ceratocanipida?, 
Ilemileucidic, Attaci, Notodontians, Cochliopodidm, and Liparida?, are arboreal in their station, 
their bodies being variously protected by spines, spinulated tubercles, hairs, or tufts. The grouj) is 
indeed i)articnlarly distinguished for the manifold modifications undergone by what are morpho- 
logically setic, and it is an interesting inquiry whether the great development of these spines and 
liairs may not have originally resulted from some change in environment, such as that from 
low-feeding to high-feeding or arboreal habits. 
It may be objected that the setm and spines were originally due to the stimulus arising from 
the attacks of parasitic insects, such as ichneumons and Tachime, or that, as hairy caterpillars 
are not usually devoured by birds, these hairs and spines have originated through natural stdec- 
tiou, and are danger signals, indicating to birds that the Avearers of such hirsute and bristling 
armature are inedible. But Avhile the final purpose or ultimate use of such an arinatiire may serve 
the useful purpose of protection, and while natural selection may have been the leading secondary 
factor in the iireservation of varietal and specific forms of hairy and spiny caterpillars, this does 
not satisfactorily account for the initial causes of the growth of tubercles, spines, etc. 
If spines and hairs form hedge-like guards against the attacks of parasitic insects, why are 
they not devehqied as well in the great multitude of low feeders as in the less numerous high 
feeders ? It may be said, however, that Euprepia caja is more subject to the attacks of ichneumons 
than almost any other larvae. (A, G. Butler in Ann. and Mag. Nat. Hist., 1891.) Everyone knows 
how efficacious any hairs or bristles are in deterring ichneumons and Tachinm from ovipositing on 
caterpillars, and it is well known that naked or slightly piliferous larvm are more subject to their 
attacks than those which are densely hairy or spiuose. 
The eniclfornt type of (arva\ — In eudeavmring to account for the origin of the tubercles and 
spines, as well as the hairs of caterpillars, let us glance at the probable causes of the origin of the 
caterpillar form, and of the more primary colors and markings of the skin. 
It was Fritz Miiller who, in his Fiir Darwin (18G4), maintained that “the so-called complete 
metamorphosis of insects, in which these animals quit the eggs as grubs or caterpillars, and 
afterwards become quiescent pupie, incapable of feeding, was not inherited from the primitive 
ancestor of all insects, but acquired at a later period.” * 
In 1869 Dr, F. Brauer^ divided the larvm of insects into two groups, the campodca form and 
raupen form, and in 1871^-1873 we adopted these suggestive views, giving the name of cruciform 
to the larvje of weevils and other coleopterous larvie of cylindrical form, as well as to the larvic of 
Diptera, Lepidoptera, and Hymenoptera, all of which are the result of adaptation, being derivatives 
of the primary campodea type of larvm. BraueFs views on these two types of larvte were also 
adopted by Sir John Lubbock in his Origin and IMetamoiqdioses of Insects, 1873. 
^ Facts aud Argumouts for Darwin, with additions by the author. Translated from the German by VV. S. Dallas, 
y. h. S., Loudon, 1869. 
^Betrachtungeu iiber die V^orwaudlung der lusekteu im Siune der Descendenztheorie. V^orh. K. K. Zool. bot. 
Oes. Wien, 1869. 
^Embryology of Chry 802 )a. American Naturalist, Sejit., 1871. 
