38 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I43 



becomes immobile and greatly contracted. When it moults, the remod- 

 eled body still within the unshed larval cuticle appears as a preliminary 

 stage of the pupa (C). An entirely new and different cuticle has 

 been secreted by the epidermis, and the larval prolegs have been 

 discarded with the larval skin. The wings are now everted, and the 

 legs have taken on more of the adult structure (H). On the head (I) 

 the large adult antennae (Ant) are conspicuous, and the mouth parts 

 are undergoing development, except the mandibles (Md) which are 

 reduced to small knobs. This concealed early period of the pupa has 

 been called the "prepupa" or "propupa," but it is not a stage of the 

 pupa equivalent to a larval instar, since it is not separated by a moult 

 from the mature pupa (D). It is therefore better named by Hinton 

 (1958) the cloaked, or pharate, pupa. By further development within 

 the larval cuticle the pharate pupa becomes the mature pupa (D) in 

 which the wings are enlarged, the legs and antennae are lengthened, 

 and the mouth parts somewhat larger. 



With the final shedding of the larval cuticle (the pupal ecdysis) 

 the fully formed pupa (fig. 16 D) is liberated. The pupal mouth parts, 

 antennae, wings, and legs lie flat against the body. In most Lepidoptera 

 they become cemented to the body by an exuding, gluelike substance 

 that soon hardens to a shell-like glaze over the entire surface. The 

 pupa is then called a chrysalis. From now on the pupa does not change 

 externally, but within it the special tissues of the larva go into dissolu- 

 tion, and adult development proceeds to the completion of the imago. 



With most Lepidoptera the mouth parts continue their development 

 within the pupal cuticle until they attain the typical adult structure 

 (fig. 17 A). In the pupa of the tent caterpillar here described, 

 however, the mouth parts actually regress from their state of develop- 

 ment seen externally on the pupal cuticle (fig. 16 J) because the moth 

 is one that does not feed. In the adult moth (fig. 17 B) the maxillae 

 (Mx) have been reduced to small, entirely separate lobes at the sides 

 of the mouth. The labium (Lb) also is much reduced, but its palpi 

 have increased to long, three-segmented appendages. There is no 

 trace of mandibles. 



The degree of change that takes place within the pupa from larva 

 to adult differs in different insects. In some, many of the larval tissues 

 simply begin a new growth that forms directly the corresponding adult 

 tissues. In others the special larval tissues break down, and their 

 disintegration may be so nearly complete that little is left of the 

 original larva. In extreme cases, therefore, the so-called metamor- 

 phosis of the insect is not literally a transmutation of the larva into 

 the imago. The caterpillar, for example, does not actually become a 



