'76 NATURAL HISTORV OF LEPIDOriEROt'S INSECTS. 



The Sphinx catalpae is the only exception yet known to this, in which 

 the horn curves towards the head of the insect. In the Pterogon ocno- 

 iiierac this horn is replaced by a lenticular spot, and in the DeilepheJa 

 vesprrtUlo it entirely disappears. 



The spines of insects are analogous to the thorns of plants, that is, 

 they only differ from bristles in being larger, harder, of a horny consis- 

 tence and more or less branching. They generally characterize the Rho- 

 palocerata, particularly the tribe of the Nymphalidae ; yet some of the 

 Heterocerata are also furnished with thera. Those belonging to the ge- 

 nus /o, have over their whole body whorls of spines which, entering 

 the hand, occasion such a pain as results from the pricking of the nettle. 

 The caterpillar of the Ceroccunpa regalis bears back of its head, and over 

 its first rings a crown of long and stout spines, which have obtained for 

 it, in JVorlh America, the name of "TAe horned devil of the SycamoreP 

 It is quite an object of vulgar terror on account of its menacing aspect 

 a«d its spines, which are supposed to occasion vexy severe pain, but ac- 

 cording to the observation of Mr. J. Leconte, it is as innocent as other 

 caterpillars. 



The colors of caterpillars are so various that it is difficult to say 

 anything that will apply generally. Nature, intent upon the preserva- 

 tion of the species, has here guarded them against the search of their . 

 numerous enemies. Those that are accustomed, like the Catocala, Ho- 

 7noplcra^ Sec, to cling to the stems of plants, are colored like bark or, 

 lichen. Such as are to live upon leaves, are colored like them or like 

 flowers. In short, their color seems adapted to their security from the 

 notice of their enemies. The color is generally constant in each spe- 

 cies ; yet there are many exceptions to this. The caterpillars of the 

 Deilcphcla elpenor^ ncrii, cclerio^ are sometimes green and sometimes 

 black. In some species no two are found of the same color. The color 

 also changes according to the age of the insect. When about to under- 

 go their metamorphosis, too, they frequently take a new and generally 

 a duller hue. The design is much more uniform than the colors ; it 

 may vary in its tints, but the spots and lines by which it is formed al- 

 ways keep their relative form and position, and though they may be ef- 

 faced or absorbed by the ground-color, yet certain characteristic traits 

 always remain. The design is generally similar in related species, 

 though this is not uniformly the case. 



Before their transformation into chrysalids, caterpillars undergo vari- 

 ous chancres of skin which are called mouJtings. These sloughings are 

 more or less numerous according to the race : Rhopalocerata generally 



