ON LARVAL HABITS. 



257 



spring. The following is a rough list of macro-lepidoptera which 

 adopt this habit, although some of those species specified continue the 

 habit throughout life: — Malacoaoma neustria, M. castrensis, M. fran- 

 conica, Laclineis lanestris, Taeniocainpa munda, T. pidverulenta, T. 

 incerta, T. opima, T. stabilis, T. popnleti, T. miniosa, Xanthia fidrar/o, 

 X. littea, Tiliacea auracjo, T. citrago, Tethea retusa, T. siibtusa, and other 

 Orthosiids ; Cleoceris viminalis, Orrhodia erythrocepliala, Asphalia ridens, 

 A. flavicorms, Cyniatophora or, C. dnplaris, Cheimatohia brumata, C. 

 boreata, Larentia dihitata, Scotosia rhamnata, S. vetulata, Leucoma 

 salicis, PortJu'sia chrysorrhnea and Aporia crataegi. 



Many nearly related species to the above, which emerge later in 

 the year, or are ground feeders, have not this habit, viz., Lasiocampa 

 qneinh, Macrothylacia rubi, Katricha qnercifoUa, Gastropacha ilicifolia, 

 OdoneMla prnni, Taenincampa gothica, Pachnobia rubricona, and P. leitco- 

 grap/ia, Orrhodia vaccinii, Orthosia hdvola, Scotoda certata, etc. 



But it is when one turns to the microlepidoptera, where the 

 habit, not only among arboreal, but also amongst low, feeders, is 

 almost universal, that another remarkable coincidence is evident. It 

 immediately becomes apparent that it is more especially small larvae 

 which have this habit, and it is amongst the superfamily of the very 

 smallest lepidoptera, viz., the NepticuUdes, that the habit of seeking 

 shelter is most specialised. In my humble opinion the habit has been 

 acquired, not as a mode of concealment from predatory enemies, 

 although I should be the last to deny that it also serves this purpose, 

 but that the primary object aimed at is protection from the elements, 

 and more particularly from the effects of heavy rain storms. 



All entomologists who have much experience in breeding know the 

 danger of giving very small larv^ wet foodplants, or of allowing 

 moisture to collect in their breeding glasses. A very small drop of 

 moisture is sufficient to drown even active larva? like those of the Cato- 

 calids, and I consider that a rainstorm would annihilate many arboreal 

 feeders if they had not adopted the habit of making themselves a 

 shelter, or by boring into buds, catkins, shoots, etc., during their youth. 

 The larvffi of most of the species given in the foregoing list abandon 

 the habit as soon as they are large enough and strong enough to with- 

 stand the elements, which seems to confirm this theory ; whereas, if 

 the habit of concealment is merely a device to escape the attention of 

 enemies, it seems rather curious that the larva? should abandon the 

 habit when they are large and conspicuous, and the larvte of most 

 microlepidoptera being small, even when fullgrown, retain the habit 

 throughout the larval period. 



Of course, to a certain extent, the webs of gregarious larv» no 

 doubt protect the larvae from cold as well as rain, such species as 

 PortJiesia auriflna, P. rhrysorrhoea, etc., which hybernate in webs, 

 undoubtedly do so as a protection against cold. I doubt whether 

 webs or concealed larvae are less subject to ichneumons than others, as 

 the latter are more probably attracted by scent than sight. 



Another matter which has been engaging my attention is canni- 

 balism. As far as I know, no one has yet attempted to explain 

 how lepidopterous larvae, which primarily were undoubtedly herbiferous, 

 have acquired this singular habit. On making a list of the best known 

 ■ cannibal larv;^, viz., Asphalia ridens, Taeniocainpa miniosa, T. gracilis, 

 ■Coswia trapezina, Hcopelosoma satellitia, Amphipyra pyramidca, Xylina 



