20. 



hours, or may last for nearly a week. In the case of the common 

 tomato-worm, Protoparce Carolina, the transformation process usually 

 requires five days ; certain species of Papilio observed took but three 

 days, but the time varies much with different individuals and the con- 

 ditions under which they live. 



When the molting fluid has done its work in loosening the larval 

 cuticle, this splits along the meson of the thorax, and is gradually 

 worked to the caudal end of the body, liberating the enclosed pupa. 

 The liberated pupa is covered with a more or less transparent cuticle 

 and resembles the pupa of the more generalized Neuroptera, Trichop- 

 tera, and Coleoptera. In all of these orders, the insects on casting 

 their larval skins show the first resemblance to the adult insect. In 

 the Neuroptera, Trichoptera, and Coleoptera, the appendages, as well 

 as the body, are encased in a pupal skin, are free from each other and 

 the body, and together with the body segments possess considerable 

 freedom of motion. This does not mean that the pupae, have any 

 power of locomotion ; on the contrary they are quite helpless, and for 

 this reason are frequently — in common with the great majority of 

 pupae — protected by some sort of a cocoon, or earthen cell. The 

 lepidopterous genus Micropteryx, which is supposed by many to be 

 the most generalized of its order, retains freedom of motion in all the 

 appendages and in all but the fixed caudal segments of the abdomen. 

 This freedom of motion is gradually lost in lepidopterous pupae as 

 specialization advances, and the adult appendages are not fully de- 

 veloped when the pupal stage is assumed, although the cases of the 

 appendages of the pupa are fully formed. Specialization in the pupa 

 consists also in the hardening of the exposed parts of the cuticle 

 through the deposition of chitin, and in the soldering of the appen- 

 dages to each other and to the body of the pupa. In the generalized 

 families the appendages are soldered to each other but often remain 

 free from the body surface; later the wings become attached to the 

 body surface, but any parts of the antennae, legs, or maxillae extend- 

 ing beyond their caudal margins remain free. The tips of these ap- 

 pendages are provided for in various ways in the higher families, but 

 are always found soldered firmly to the surface of the body of the 

 pupa. Proceeding hand in hand with the soldering down of the ap- 

 pendages is the loss of motion in the abdominal segments. Among 

 certain families there is motion between all of the adjacent segments. 

 There is, however, a successive loss of motion between segments, until 

 the conjunctiva between all but two of the segments is inflexible in 

 some forms, and even in some of the Lepidoptera, entire freedom of 

 motion has been lost in all of the segments. 



