INSECTS. 273 
amongst the winged there are many, which undergo no other meta- 
morphosis than that they obtain wings. Their /arve resemble the 
perfect Insect, but are quite without wings: the pupe have rudi- 
ments of wings and move themselves: in the last moulting these 
wings become developed and perfect. These Insects undergo 
accordingly an dmperfect metamorphosis (demi-metamorphose La- 
TREILLE, metamorphosis tncompleta); this is the case, for instance, 
with the grasshoppers. Most winged Insects, lastly, are subject 
to a perfect metamorphosis (metamorphosis completa), as we have 
described it in butterflies; the pupa takes no food, and remains in 
a state of rest or slumber. The pupe of flies are entirely motion- 
less, surrounded by a hard shell, and shew no limbs of the perfect 
Insect concealed beneath it; this shell is formed by the dried 
integument of the larva. Such a pupa is named pupa coarctata. 
In other dipterous Insects and in the Lepidoptera there is a hard 
elastic membrane, surrounding the enclosed compressed external 
parts of the future perfect Insect, and so disposed that they can be 
distinguished through the covermg. Such a pupa is named pupa 
obtecta ; such pup move the rings of the abdomen. In still other 
instances the wings and feet are free, without being surrounded by 
a common covering, as in the pupe of beetles and bees. 
These changes are not confined to the external parts; in the 
internal structure also very remarkable changes occur. The intes- 
tinal canal is in most larvee straight, and consists principally of a 
wide stomach. ‘The cesophagus and the part of the intestinal canal 
behind the stomach are longer and narrower in the pupa and in 
the perfect Insect, since the stomach contracts and is more definitely 
separated from the rest of the intestine. The nervous system becomes 
1 For pupe of the last kind the word nympha is sometimes specially used ; see 
SWAMMERDAM, Bibl. nat. pp. 10,16; Buapu, Pundamenta Zoologie, in Linn. Amenitat. 
Acad. Tom. VII. p. 151; Newport in Topp’s Cyclop. 1. 879. 
LINN2ZUS names a pupa complete (pupa completa), which moves itself, and in all 
respects resembles the perfect insect ; half-complete (semi-completa), that which is at rest 
and takes no nutriment. Syst. nat. Ed. 12,1. p. 534. Fapricrus transferred these 
names improperly from the pupa to the metamorphoses, and thus named complete 
metamorphosis (metamorphosis completa), that which, in fact, is no metamorphosis, as 
in the myriapods, the spiders, &c. The metamorphosis which LATREILLE names 
complete (cx. gr. that of butterflies, beetles) FaBRioruS names incomplete (incompleta) ; 
the semi-metamorphosis bears with him the name of metamorphosis semi-completa. See 
Fasricius, Philos. Entom. p. 56. 
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