18 MODERN CLASSIFICATION OF INSECTS. 



whereas this kind of metamorphosis is the most complete of any of 

 the changes which insects undergo. This impropriety has resulted 

 from the improper application of the Linnsean terms employed for the 

 designation of the pupa : (Pupa completa, Spiders, &c. ; semicompleta, 

 Grasshoppers, &c. ; incompleta, Bees, Ants, &c.; obtecta. Butterflies 

 and Moths ; and coarctata, two-winged Flies.) 



"When the insect has remained a certain period in the pupa state 

 it again sheds its skin and appears in its perfect and final state ; at 

 first, indeed, its external envelope is humid and soft, but it soon dries 

 and hardens by exposure to the air, acquiring at the same time its 

 various colours. These modifications in the outer forms of insects 

 are also accompanied by equally important changes in their internal 

 structure as well as by the modifications in the economy of the insect 

 consequent thereon. 



III. Distribution of Insects into Orders. 



This branch of Entomological Science has attracted much of the 

 notice of naturalists in all ages ; but it was not until the era of 

 Swammerdam and of Ray, that philosophical principles were 

 introduced and made the basis of the distribution of insects into 

 primary groups. As, however, most of the systems of Entomology 

 have been noticed at considerable length in the fourth volume of 

 the Introduction to Entomology, I must refer the reader thereto, 

 deeming it, however, essential to offer a few observations thereon. 



Previous to the age of Swammerdam, the most vague ideas were 

 entertained with respect to insects, of which the fanciful hypothesis 

 of spontaneous generation was one of the most absurd. Hence, it is 

 not to be wondered at, that Swammerdam (who together with Redi and 

 Ray completely overthrew this system by establishing the theory 

 of the universal developement of animals, ex ovo) was led to consider 

 the principle of metamorphosis which he had so successfully employed 

 against the spontaneous generationists, as of primary importance for 

 the classification of insects. Indeed it is evident that the very nature 

 of his studies, by which he had obtained so great a victory, could have 

 had no other effect than to liave produced the Metamorphotic System 

 of Insects, detailed in his surprising and still invaluable Biblia Nature, 

 and in which four primary divisions are established. 



1. Insects subject to a change of skin, but undergoing no change 

 of form. (Spiders, Lice, Woodlice, and Centipedes.) 



