INSECTS. 273 



amongst the winged there are many, which undergo no other meta- 

 morphosis than that they obtain wings. Their larvce resemble the 

 perfect Insect, but are quite without wings : the pupce have rudi- 

 ments of wings and move themselves : in the last moulting these 

 wings become developed and perfect. These Insects undergo 

 accordingly an imperfect metamorphosis (demi-metamorphose LA- 

 REILLE, metamorphosis incomplete^ this is the case, for instance, 

 pith the grasshoppers. Most winged Insects, lastly, are subject 

 a perfect metamorphosis (metamorphosis completa), as we have 

 escribed it in butterflies ; the pupa takes no food, and remains in 

 state of rest or slumber. The pupse of flies are entirely motion- 

 ess, surrounded by a hard shell, and shew no limbs of the perfect 

 nsect concealed beneath it ; this shell is formed by the dried 

 ntegument of the larva. Such a pupa is named pupa coarctata. 

 n other dipterous Insects and in the Lepidoptera there is a hard 

 lastic membrane, surrounding the enclosed compressed external 

 arts of the future perfect Insect, and so disposed that they can be 

 istinguished through the covering. Such a pupa is named pupa 

 btecta ; such pupae move the rings of the abdomen. In still other 

 nstances the wings and feet are free, without being surrounded by 

 common covering, as in the pupaa of beetles and bees 1 . 



These changes are not confined to the external parts ; in the 

 nternal structure also very remarkable changes occur. The intes- 

 inal canal is in most Iarva3 straight, and consists principally of a 

 vide stomach. The oesophagus and the part of the intestinal canal 

 >ehind the stomach are longer and narrower in the pupa and in 

 lie perfect Insect, since the stomach contracts and is more definitely 

 eparated from the rest of the intestine. The nervous system becomes 



1 For pupce of the last kind the word nympha is sometimes specially used ; see 

 WAMMERDAM, Bill. not. pp. io, 16; BLADE, Fundamenta Zoologwe, in LINN. Amtenitat. 

 [cad. Tom. vn. p. 151 ; NEWPORT in TODD'S Cyclop, n. 879. 



LINNAEUS names a pupa complete (pupa completa), which moves itself, and in all 

 espects resembles the perfect insect ; half -complete (semi- completa), that which is at rest 

 nd takes no nutriment. Syst. nat. Ed. is, I. p. 534. FABRICIUS transferred these 

 ames improperly from the pupa to the metamorphoses, and thus named complete 

 netamorphosis (metamorphosis completa), that which, in fact, is no metamorphosis, as 

 n the myriapods, the spiders, &c. The metamorphosis which LATREILLE names 

 omplete (ex. gr. that of butterflies, beetles) FABRICIUS names incomplete (incompleta) ; 

 he semi-metamorphosis bears with him the name of metamorphosis semi-completa. See 

 FABRICIUS, Philos, Entom. p. 56. 



VOL. I. 18 



