42 INTRODUCTION. 



the Ametabola. This is a bifid fleshy organ ox furcula, situated between the head 

 and the first segment of the neck, which the caterpillar can protrude or retract at 

 pleasure, and either employ as a means of defence or as an osmaterium. I have to 

 resretthat in the illustrations which I exhibit of the larvae of Javanese Papiliones, this 

 character is not always expressed in its full development ; while submitted to the 

 draughtsman this organ was naturally retracted, but there is sufiicient evidence of its 

 existence in the individuals represented, and in fig. 13 of pi. iv, it is partially 

 protruded. In a figure, borrowed from Abbot, it appears in a state of complete 

 development. The analogy afforded by this organ to the Chilognatha is not obscure, 

 and will be more particularly referred to in the sequel. Another peculiarity of the 

 larva of the typical genera of this stirps, is the manner in which the head is attached 

 to the body : it is by the intervention of a very small articulation, so that the head, 

 when exserted, appears separated from the body. This pecuHarity is introduced by 

 Ochsenheimer into the general character of the Papiliones; ; it is indicated by the 

 authors of the Vienna Catalogue in the following words : " Die Raupen hahe^i den 

 kugelichten Kopf merklicher vom Leibe abgesondert" See p. 158. 



The pupa or chrysalis of the Chilognathiform stirps, agrees in its attachment and 

 mode of suspension with that of the Vermiform stirps, but it has some peculiarities which 

 indicate a greater perfection. The caudal extremity is firmly attached by a few threads 

 or by a silky filamentose texture, which sometimes resembles a cord ; (See fig. 13, a, 

 pi. ivj, while the anterior end is either free and detached, or leans slightly against 

 some support, (a wall, a tree, &c.), in a perpendicular attitude, the thorax du-ected 

 upwards ; or it stretches forward nearly horizontally, being in both cases fastened and 

 supported by means of a thread passing as a brace across the thorax. It is naked 

 and angulated, but much diversified on the surface ; the tubercles, always regularly 

 disposed, vary according to the species ; it is terminated, in the typical forms, at 

 the upper extremity, by two processes ; those species, however, which are at the 

 confines of the Vermiform stirps, have only one short process, more or less acute : 

 as the series approaches the Chilopodomorphous stirps, we find the same mode of 

 suspension which prevails in that group ; the chrysalis is attached by the tail, while 

 the thorax is directed downward. An example of this is given in the fourth plate, 

 fig. 13, a. Here the pupa has a perpendicular direction ; but a fastening or brace 

 stiU exists, by which it may, in some instances, preserve a partially horizontal 



attitude. 



The imago or perfect insect of this stirps exhibits in the typical group the most 

 perfect production of the whole order. The beauty of many of the large Papi- 

 liones is a subject of universal admiration: several of them are unrivalled in form and 

 colouring. The stirps, as limited by the larva, embraces several of the first divisions 

 made by Linnaeus in the genus Papilio : the Equites and Dandi, and the Heliconii 



stand 



