l.NTKDlK'tTIoN 



ahdomcn, or 8U])])()rte(l in an uprii^'ht attitudr )»y a rTomnstor o 

 silken cable i)asse(l round it and attaclied to contiguous o)>jecta, an 

 irwanoiis '^T(m])s of Pdjril iout's; or, in nuiiiy .Vor/«iW«r, Ctratocatnjndtff 

 etc., simply })nried in the eartli. 



Tni Pita. 



Having formed its cocoon, the larva turns to a pupa, during 

 which stage in some />ljitinf almost tin* whole of the tissues of the 

 body unchrgo degencTation into a liijuid fifty substanci* within the 

 outer cuticle, except the nerve eentre> and >ome bodies attaclied to 

 them known as the " imaginal disks,'" which are tiie rudimonlM 

 of the future body, wings, and legs, and which by absorption of the 

 products of the <iegenerated tissues gradually gn)W and build up 

 the imago till ready to emerge from tiie puj»a skin. In the Af*y)i- 

 (lopttni, however, tlii> jirocess is not carried nearly so far; the 

 dorsal vessel and its mnschs. some skin muscleH, tin* tracheal system, 

 and the alimentary canal of the l.irvie are persistent, and tlie niouth- 

 parts, antenna', and legs of the imago are moditied ami developed 

 from those of the larva- : tin* prociss, in fact, resolvirjg itself into 

 the imaginal structures not present in the inrvie being develojK'd 

 from disks, whilst the larval strut lures not pn'sent in the imago 

 undergo degeneration. 



The various parts of the jnipal skin are all soldered together 

 and immovable, exce|4 certain of the abdominal somites, but the 

 head with the cases for the probo.'-cis and antennir, the thorax with 

 the wing- and leg-eases, and the alKlominal somites can be easily 

 distinguished. 



Emkhoknck ntoM Cocoox. 



In the orders of insects of which the imagines are jjrovided with 

 jaws, these are used to help them to force their way through the 

 cocoon, and Er'u.ct ithnla being j>rovided with functional jaws pro- 

 bably uses them for the same purpose. The evolution of the 

 haustellate Ljtidopfern resolves itself into the solution in various 

 ways of the ]iroblem of freeing themselves from the eoeoon without 

 jaws *. In this resjKot the famdies fall into two main divisions t : — 

 (1) The yyj<*o;//^)/</«#, with the 7th abd«miinal segment tree in the 

 male, fixed in the female, the moth emerging from the cocoon 

 clothed in the effete pupal skin; of thc^o Microjtfcrif.v :X uses the 

 jaws of the puj)al skin to rupture the cocoon and to pass through 

 it and overhnng earth, motion being induced in them 1)y vermicular 

 movements of the pupa. In all other Ix^pidoptera the pupal jaws 

 are functionally obsolete, accompanied by considerable consolidation 

 of the previously movable parts, and a roughening of the dorsum 



* Dr. T. A. I). Chapman. Tmns. Ent. Soc. 18(>0, pp. r^Gl-bS't 

 t Id., Trans. Ent. Soc. 189.3, pp. 07-110. 

 + Id.. Trans. Ent. Soc. 1803, pp. 2.3:>-2<)r>. 



