THE GREGARIOUS HABIT IN BUTTERFLY LARV^. 17 



described by Edwards as laying its eggs in clusters of a few to about a 

 hundred, and Scudder says (op. cit., p. 664) that " the larvae are gregarious 

 when young, and, when alarmed, they immediately loosen their hold on 

 the leaf and fall to the ground with their bodies bent in a circle . . 



. They spin a slight web on a leaf when they wish to moult, but 

 do not construct one for concealment or protection at any other time, 

 hybernating without that aid." Yet another Melitaeid, Phyciodes 

 tharos, lays its eggs in clusters, Edwards says (Can. Ent., xvi., p. 114), 

 " but the larvae do not cover themselves with a web, but lie naked on 

 the leaves, coming together and forming clusters when the moults take 

 place." Scudder says that " the gregarious larvae of P. tharos feed in 

 close company, always on the under surface of the leaves, moving up or 

 down, but generally down, the plant, as they need fresh pasture, but 

 without spinning any web, and continue thus until hybernation, when 

 they leave the plant, and wander more or less, bat still, in some degree, 

 in company. After hybernation they feed up apparently solitarily " 

 (Butts. New Engl., i., p. 637). 



We have given in detail Scudder's notes on the gregarious larvae of 

 these New England Melitaeid species, as illustrating their similarity to 

 those of Europe, and to enable our European lepidopterists, conversant 

 only with the larval habits of the Palaearctic species, to compare the 

 latter therewith. Scudder says (op cit., p. 619) " the Melitaeids are 

 mainly characteristic of the New World, where they abound in the 

 tropics and north temperate zone, but are also well represented in all 

 the northern parts of the Old World .... The eggs are generally 

 (perhaps always) laid in clusters, and the caterpillars, at least in the 

 early half of their lives, are social, often constructing common webs, 

 in which some kinds hybernate .... In one Pacific 

 coast species, Henry Edwards says that each individual makes 

 a separate web of its own. The web-constructing habit appears to be 

 confined to, and almost universal in, that tribe which is best developed 

 in the Old World, and on the Pacific slope of our own country, in 

 distinction from eastern America, and the tropics. To it belong 

 Cinclidia and Euphydryas of our New England genera," the gregarious 

 habits of the larvae of the species of which have just been fully dealt 

 with (supra). 



We have already noted the gregarious habits of the young larvae of 

 Melitaea cinccia, and have further observed that they retain some 

 measure of the social habit after hybernation and until fullfed. The 

 web in which they spend their early lives is thin and open, and largely 

 serves as a carpet to lead from one part of their foodplant to another, 

 but that in which they hybernate is close and compact, spun low down 

 near the ground, entirely different from that in which they feed, and is 

 woven of silk, with grass and plantain stems interwoven, so that the 

 inside of the structure is quite dry. Luff says that, in the spring, they 

 spin another web, on their foodplant, much less compact than the 

 winter-nest, although larger. Most of the larvae, when nearly full- 

 grown, leave this nest, and live singly, but others keep to it and live 

 more or less gregariously even up to the time of pupation. The larvae 

 of Melitaea aurinia live similarly, leaving their hybernacula regularly 

 in March, and living singly. One unusual occurrence has been recorded 

 (Ent. Rec, xix., p. 74) by Head, who notes that the larvae of this 

 species sometimes hybernates over two winters. He says that, on 



