12 MEMOIKS OF THE XATIOXAL ACADEMY OF SCIENCES. 



Of till' great groiiii of Geometiidu' many kinds arc arboreal (Dcndiogeonietiids), and in 

 such cases are aliliost Invariably tuberculated in manifold ways. We know of no liairy or tufted 

 caterpillars of this group or of any family below them, with the exception of the Pterophoridie. 



Tiie arboreal I'yralida-, Tortricida-, 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 tuberculated or spiny; in fact, we can not recall one of these groups which 

 are s,-/. The Pterophoridic are, to be sure, spiny, but they are low feeders, and their peculiar 

 excretory setse (the Driiseuhiirclieii or glaiulular hairs of /eller') are sinnlar, as Dimmock has 

 observed, to the glandular or long hairs of plants; Miss Murtfeldt adding that "there is a very 

 close imitation iu the dermal clothing of the larva? [of Lcioptil us Hericiduetylus] to that of the young 

 leaves of Vernonia, on wliich the spring and early summer broods feed." (Psyche iii. 390, ISSii.) 



Keturniug to the Bombyces, all the Xotodontians, without any exception, known to us have 

 trees as their principal, if uot exclusive, food plants. Thus, of the 37 species of this group whose 

 larval forms are known, and which are enumerated in Mr. H. Edwards's ''Bibliographical catalogue 

 of the described transformations of North American Lepidoptera," together with an additional 

 species {Ichthjjiira.siriij<mi) omitted from the catalogue, all are known to feed on trees, unless we 

 except Batiina mujur, which feeds on Andromeda. It is noteworthy that the (uily S])ecies found 

 thus far on a herbaceous plant is the cateri)illar of Apaiclodcs tonr/avfa, 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 ditters markedly from the nurjority of the Lithosians and Aictians, unless we except 

 the Xolida». Now the larva of Apatelodes is hairy, the long, white hairs having scattered among 

 them black ones, with more or less black pencils, thus resendiling the peculiar yellowish or white 

 caterpillars of Halesidota, with their black tufts and pencils. Similar forms are some of the 

 arboreal, hairy Noctuid;e, as Charadra dciidens. It .seems evident that the resemblance to each 

 other in such difiereut groups is the result simply of adaptation, brought about by two factors, 

 the primary one being a change from a lowfeediug to an arboreal station, and consequent isolation 

 or segregation, and the secondary one being natural selection, the latter further tending t(j i)re- 

 serve the specific form. 



It will be seen by the following review that the North American Bombyces in general, with 

 the exception of the Arctians and Lithosians, live on trees, and this will in general applj' to the 

 Old World species. In the group of Lasiocampida-, represented by Tolype, Artace, Ileterocampa, 

 Gastropacha, and Clisiocampa, the station is an arboreal one, none being known to feed on 

 herbaceous plants. All the Ceratocami)ida', all tlie Hemileucida' and Attaci, the Platyptericida', 

 all the Cochliopodidie (Limacodes), including both the naked and spiny genera, as well as the 

 P.sychidie, live exclusively on trees. Of our North American Liparidie, all are aiboreal in station, 

 except the (Jalifornian Orfpjui rctusia, which lives on the lupine. Finally wc come to the Arctians 

 a:id Ijithosians, whose hairy, or rather setose, larvie in general feed on herbaceous plants and 

 .sometimes on trees, being in many cases ouuiivorous, while those of the Nolida' and Nycteolidse 

 whose history is known, are arboreal. 



Of the Zygicnidie, including the Cteuuchida'. the species are low feeders, living on lichens, 

 grasses, and other low plants, or upo7i vines. The Uioptid genus Phryganidia feeds on the oak. 

 Of the Agaristid.e, some are low feeders, Euscirrhopterus (jlovcri feeding on Portulaca, while the 

 majority prefer vines (Vitis, etc.). As to tlie boring habits. of the Hepialida^ and Cossida% 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, Notodontiaus among them, which in this Northern States feed on trees alone, in the Gulf States,, 

 aicordiui; to Abbott, feed on shrubs, vines, and low ]ilants, as well as trees. 



In reply to an inquiry, Mr. \V. H. Kdwards kindly writes nie: "1 do not think that the biiturlly larv;r whiih. 

 live on trees are under more favorable conditions than low feeders as to healthiness or ease of rearing.'' 

 'Revision der Pterophoriden. Linu:ea entoin., 1S.52, vi, 3r>i;. Xli-ntioueil by DiiMiuock. 



