162 THE BUTTERFLIES OF NEW ENGLAXIX 



For these papilliform bodies, however developed, :irc rarely simple. 

 Thev nearly always terminate at the summit with a single tapering hair, 

 and in this form they very generally cover the body of the caterpillars of 

 all butterflies, however naked they may appear, however hirsute, or however 

 bristling with spines. In the earliest stage, especially in the young of 

 many Nymphalidae and Lycaenidae, the hairs are of excessive length, and 

 microscopically spiculiferous or serrate. Sometimes the hairs are clul)bed 

 at the tip oi- trumpet-shaped, as witli many of those found on the body of 

 Pierinae, as also upon the Hesperidae in their earliest and occasionally in 

 their later stages. The trumpet-shaped or club-shaped hairs appear to 

 be hollow canals through which fluids may be forced, for one may discover 

 the use of the expanded and probably hollowed extremity, in the somewhat 

 rapid appearance of the minutest possible globide of fluid at the tip of a 

 hair Avhere none could be seen shortly before. Not infrequently the hairs 

 are of equal size throughout and truncate at the tip, as in some Pierinae 

 and Lycaenidae, but neither in this case nor the preceding are these special- 

 ized hairs the only ones found upon the bod}-, but they are certain special 

 hairs, often assuming a definite position amid a mass of simple tapering 

 hairs, seated on precisely similar or simply smallei" papillae. In very rare 

 cases the hairs may even be forked ; we have in our fauna only a single 

 striking instance of this, in the caterpillar of Iphiclides ajax at birth, but 

 such instances, none of Avhich I believe have been specially noted before in 

 Lepidoptera, must be excessively rare. Reaumur figures the larva of one 

 of the hymenopterous family Tenthredinidae with similar appendages at 

 maturity. 



If we follow the caterpillars of the Vanessidi from their first stage, in 

 which we find the simple papilla terminated by a long hair, we shall find 

 that after the first moult this papilla is considerably larger, while the hair 

 is diminished very much in length and importance ; and following it stage 

 by stage we see the papilla at last developed into a horny spine terminated 

 at the tip in a little bristle, and armed all along its sides, often in regular 

 series, with secondary spinules which also terminate in a bristle and bear 

 minute, setigerous papillae. Between these juvenile and mature stages 

 there is every development of this spine, and if we look through the entire 

 series of the Nymjjhalidae we shall find a considerable variety in the form 

 which these spines assume (PI. 86). In some, as in Euvanessa antiopa, the 

 main spine is only furnished in the final stage with minute bristle-bearing 

 papillae in place of the spinule with its armature ; and the main spine in this 

 case is prolonged to an excessive extent, although not to so great a degree 

 of slenderness as in Heliconia. In others, the main spine becomes rather 

 a coriaceous conical tubercle beset with bristle-bearing papillae, as in the 

 Melitaeidi and many jVrgynnidi. 



Finally there is another form of appendage, which differs from the others 



