144 ZOOLOGY. 
which the former contains two: 1, Lehynchota ; 2, Gymnognatha ; and the 
latter four: 38, Antlcata, Fabr. (Diptera, Linn.); 4, Pezata, Fabr. (Hymeno- 
ptera, Linn.); 5, Glossata, Fabr. (Lepidoptera, Linn.); and 6, Hleutherata, 
Fabr. (Coleoptera, Linn.). For all these, except the second, Burmeister adopts 
the names of Fabricius. The peculiarity of this arrangement is the reduc- 
tion of the orders to six, and the distribution of the minor parts of each, as 
will be observed in the following sketch. 
The /¢ehynchota are made to iiekale the tribe and family Paice (the 
lice), or haustellate Anoplura ; whilst the mandibulate Anoplura, or bird 
lice, form the second tribe of his order Gymnognatha, under the name of 
Mallophaga, the first tribe being the Physopoda, from which Haliday and — 
most English entomologists form their order Zhysanoptera. The order — 
Thysanura of preceding authors forms a tribe, next to which succeed the 
Orthoptera (including Llatta); Dermatoptera (forficula, pl. 81, figs. 1-8) ; 
Corrodentia (Termes, Hinbia); Subulicornia (Kphemera, Libellula) ; 
Plecoptera (Semblis); Trichoptera ; and Plannipennia (Sialis, &c.), all as 
tribes of the same order. It results from this, that the Mewroptera and 
Orthoptera, as well as other groups usually considered orders, form but one 
order, in the opinion of Burmeister. Erichson (in Agassiz’s Nomenclator) 
places the Thysanura as an order, except that the Lepismide are withdrawn 
and placed in the order Orthoptera, which is further enlarged by the 
addition of the Libellulade, which are abstracted from the remaining 
Neuroptera. Erichson admits the orders Thysanoptera, Hpizoa (lice), and 
Suctoria (fleas). 
Burmeister states the principle upon which he establishes his orders as 
follows: ‘‘The more marked the transformation the more heterogeneous is 
the individual in the several stages of its existence; and as all insects 
proceed from the same point, those necessarily, whose metamorphosis we 
call complete, must attain a higher grade than the rest, which transform 
themselves incompletely. We thus obtain two chief groups among insects, 
Henumetabola and Holometabola. Both commence a new development in 
the organization of the mouth, as they at first exhibit to us abortive, setiform, 
oral organs, only adapted to suction, but in the higher grades these suctorial 
organs develope themselves into free mandibles, with a lip covering them. 
Thus each group has Jnsecta haustellata and Insecta mandibulata. Each 
of these groups may then be further subdivided, according to the form of 
the larva, the structure of the wings, and the entire internal organization, 
and these divisions constitute their orders. We thus obtain an arrangement, 
the principles of which are deduced from the idea of the entire insect, and 
which, as this idea becomes separated according to its several characters 
and constituents, it consequently necessarily and spontaneously forms itself 
by the philosophical laws of thought.” 
The orders of Latreille will be chiefly followed here, not because they are 
considered to be correct, but because the accuracy of the modifications 
proposed by Erichson and Burmeister has not been sufficiently tested. 
Moreover, the views of these celebrated entomologists do not correspond. 
Orver 1. Tuysanura (pl. 77, figs. 79-84). In this order, established by 
348 
