26 MODERN CLASSIFICATION OF INSECTS. 



' lappers.' " And at a subsequent page (vol. iv. p. 366.), they regard 

 Clairville's Mandibulata and Haustellata as secondary groups*, " be- 

 ing convinced from the numerous characters they possess in common, 

 notwithstanding the different mode in which they take their food, 

 that they form one connected primary group ; in which opinion they 

 are further confirmed by the variations that take place in their mode 

 of feeding in their different states ; some from masticators becoming 

 suctorious (Lepidoptera), and others from being suctorious becoming 

 masticators, (Myrmeleon, Dytiscus) ; which shows that this character 

 does not enter the essential idea of the animal." 



Much of the difficulty which has arisen upon this branch of our sub- 

 ject has been produced by regarding the relations of insects as exhibit- 

 ing themselves only in a linear series. It is not necessary for me here to 

 advocate either the quinary or the circular disposition of groups; but 

 when I perceive that, by quitting the linear series we gain a decidedly 

 greater number of points of contact, whereby groups, which in such 

 linear series must be kept widely apart, are brought into juxta-posi- 

 tion, I cannot but think, that some other than an undeviating chain 

 of linear affinity is the correct mode of viewing the productions of 

 nature. Now, Mr. MacLeay, by his system (which may be termed 

 the Representative System), has obviated more of the difficulties 

 already pointed out, than could by possibility be effected by any of the 

 previous systems. Here, indeed, as he observes, in the Ho7'cb Ento- 

 mologiccE^ '' a beautiful regularity is perceivable, comprising those dis- 

 tinctions of Trophi, insisted upon by Fabricius, Cuvier, and Lamarck ; 

 those relations of metamorphosis, constituting the leading principle 

 of De Geer, Olivier, and Latreille ; and, finally, those characters from 

 the organs of locomotion, upon which orders were founded by Aris- 

 totle, Ray, and Linnaeus." 



By reminding the student, that in the following tables the first and 

 fifth order in each series are supposed to be as nearly related to 

 each other as any other two contiguous orders (each series returning 

 into itself and forming a circle), an idea may be gained of Mr. 

 MacLeay's mode of distribution. The names printed in italics are 



* Mr. MacLeay, in order to establish a quinary distribution of the Annulosa, con- 

 sidered the Mandibulata and Haustellata as classes, each possessing an equal rank 

 with the Crustaccii, Arachnida, and Ametabola. I cannot adopt this view ; which, 

 indeed, Mr. MacLeay has himself partially modified in his Memoir in the 14th 

 volume of the Linncean Transactions, 



