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The pllpa has so many of the characters of the mature insect that we lnight sa? / it is self-evident that it is a part of the adult stage, except that to say anything is "se]f- evident" is almost an unpardonab]e remark in scientific writing. However, it is clear to the eve that the pupa, in casting off the skin of the ]arva, has'entirely discardcd the larva] for/n, except in certain insects t?]at have a larva] form in the adult stage. The pupa llliiV rctain a few Ulfimportant ]arval characters, but all its principal organs are th-se of an adult insect in a ha]fway stage of development. In studying the cicada, it.was«fi»servcd that the adult issues from the skin of the nymph in a very immature condition. A carefid dissecti«m «?f a specime?? at this rime would show that the creature is still imperfect in many wavs besides those which appear externallv. By very rapid ?rowth during the course (,f an hot/r, ho?veve?, the adult form and organs are perfected. We have also noted that with insects of incomplete metam-rphosis the adult is mostly formed within the nymphal skin some rime before thë latter is cast off. The same thing is true of a pupa. For several davs bel.re the caterpillar is ready to molt the last rime, i't remains ahnost motionless and "its Imdv contracts to perhaps less than hall of the original len?th. The caterpillar is now said to be in a "prepupal" stage, but examination of a specimen will reveal that it bas alread? transfc?rmed, f-r inside its skin is a sort pupa in a préliminary stage of development (l;ig. ?4? B). This first stage of the pupa of a moth or butterfly (Fig. ?41 B) is entirely comparable with the immature adult of the cicada fi»rmed inside the skin of the last stage of the nymph (Fig. ?4 ? Al. The entire pupal period, therefore, corresponds with the formative stage of the cicada, which begins within the nymphal skin and is com- pleted about an hour after the emergence. The only external différence between the two cases is that the pupa sheds its skin, making a final added molt before it becomes
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