CLASSIFICATION 177 



It must be admitted that whichever of the three systems we 

 have sketched be adopted, the result is, as regards both these 

 points, open to criticism. The Order Xeuroptera, if we take it 

 in the broad sense, differs from the other Orders in the greater 

 variety of metamorphosis exhibited by its members ; while if, on 

 the contrary, it be dismembered, we get a number of groups 

 of very unequal extent and not distinguished from one another 

 by the same decisive and important characters as are the other 

 Orders of which they are considered equivalent. The discrepancy 

 exists in nature, and can scarcely be evaded by any system. A 

 similar observation may be made as to the parasitic groups, 

 viz. Mallophaga, Anoplura, Aphaniptera, and Strepsiptera. It' 

 these be treated as separate Orders the result is not satisfactory ; 

 while, if they be associated with the larger groups to which they 

 are respectively nearest allied, it is almost equally unsatisfactory. 



"We may mention that Packard and Brauer have in their 

 treatises discussed the question of super-orders, and have gone so 

 far as to propose names for them. These two authorities do not 

 however agree in their conclusions ; and as the names proposed are 

 of little practical value, and are but rarely met with, we need not 

 explain them or discuss the comparative merits of the two systems. 



The divisions of inferior value to the Order are, after repeated 

 scrutiny by man}" naturalists, becoming of a more satisfactory 

 character, and notwithstanding various anomalies, may be, many 

 of them, considered fairly natural. 1 Unfortunately entomologists 

 have not been able to agree on a system of terminology, so that 

 for these subdivisions terms such as sub -order, series, legion, 

 section, tribe, etc., are used by different authorities in ways 

 so various as to cause much confusion. In the following pages 

 the terms sub-order and series will be used in a somewhat vague 

 manner, the term sub -order being preferred where the group 

 appears to be an important one and of a fairly natural character, 

 while the word series will be adopted when the groups are con- 

 nected in a conventional manner. The designation " family " 

 will be used for groups of subordinate importance : and as regards 

 this term we may remark that systematic entomologists are 

 making genuine efforts to define the " families " in an accurate and 

 comprehensible manner. The endeavour to make these systematic 



1 The term natural is here employed in the empirical sense described by Brunner 

 von "\Vattemvyl, Nouv. Syst. Blattaircs, 1865, p. vii. 



VOL. V N 



