206 CLASSIFICATION OF INSECTS. 



They who have only superficially glanced at this system 

 find a ready argument against it in the obvious difficulty of 

 resolving all groups into any uniform number of divisions, 

 and thus they set a stumbling-block at the very threshold 

 of the enquiry. The preponderance of the number seven 

 is apparently the effect of the centrality of types, precisely 

 as the hexagonal cells of a bee-hive result from the pressing 

 together of circles. But neither in the centrality of types, 

 nor in the mystic number seven, is the test of the septen- 

 ary system. Systematists have always insisted on some 

 one or two characters which they conceived to be of greater 

 value than certain other characters : thus Swammerdam 

 believed that in the preparatory states of an insect was to 

 be found the clew to its natural situation : Linneus, whose 

 name is familiar to every child who has ever sought out the 

 name of an animal or plant, believed that difference in the 

 structure of the wings afforded the best divisional charac- 

 ters : and lastly, Fabricius, discarding the ideas of Swam- 

 merdam and Linneus, insisted that in the variations of the 

 mouth was to be found the key to natural aiTangement. 

 Thus we have three systems ; that of Swammerdam, or the 

 "metamorphotic," that of Linneus, or the "alary," and 

 that of Fabricius, or the " maxillary." All naturahsts have 

 acknowledged the merits of one or other of these systems, 

 and the numbers in favour of each may be said to be 

 nearly balanced. Latreille, the great master of modern 

 Entomology, not knowing to which of the three to give 

 the preference, proposed a fourth, in which he attempted 

 to combine the other three ; but in tliis he failed, owing to 

 his adherence to the belief that no arrangement otherwise 

 than in a right line could be in accordance with the plan of 

 nature : Latreille's system was called the " eclectic." 



Now although the metamorphotic, alary and maxillary 

 systems are so carried out as to be at variance with each 



