INSECTA. 



855 



of the circulatory and digestive organs in the 

 molluscous classes has induced them to place 

 these, which in other respects are inferior 

 in development, above the Articulated. We 

 cannot, however, agree with those who consider 

 the organs of nutrition alone of sufficient im- 

 portance to allow of this deviation from the 

 fundamental principle of arrangement, neither 

 can we admit with others that the nervous 

 system of the higher Articulata is inferior to 

 that of the higher Mollusks, the Cephalopoda, 

 while we ourselves claim for the higher Articu- 

 lata the most decided superiority in the next 

 essential character of arrangement the deve- 

 lopment of the skeleton and organs of locomo- 

 tion. 



Without entering further upon this difficult 

 subject, we will simply state our conviction 

 with Carus, Burmeister, and others, that the 

 articulated ought to stand at the head of the 

 invertebrated classes, seeing that they contain 

 among them some of the most completely 

 organized of invertebrated animals. We shall 

 reserve for the present our explanation of the 

 steps by which we propose to pass from the 

 lowest vertebrated forms to these, in our esti- 

 mation, the highest of the invertebrated, and 

 proceed to consider the arrangement of Insects, 

 as a class, as proposed by different naturalists, 

 before we enter upon an examination of the 

 peculiarities of these animals. 



The principles upon which naturalists have 

 attempted to arrange this interesting class have 

 been almost as various as the systems proposed. 

 Aristotle among the ancients arranged Insects 

 with reference to the presence or absence of 

 the organs of flight ; and although he was far 

 more successful than many of his successors in 

 separating from Insects the Crustacea, as a dis- 

 tinct class, his arrangement of Insects is not 

 entirely natural, since it separates some of the 

 most nearly connected families. Among the 

 moderns, Aldrovandus, in the beginning of the 

 seventeenth century, divided them into land and 

 water Insects, and subdivided these groups into 

 families according to the structure of their 

 wings and legs. Swammerdam many years 

 afterwards first proposed to arrange Insects 

 with reference to their metamorphoses; first, 

 those which undergo only a partial or incom- 

 plete metamorphosis, and, secondly, those which 

 undergo a true or complete one. The latter he 

 again divided into those which undergo a slight 

 change of form, but are active during the pupa 

 state ; secondly, those which have distinct limbs 

 but are inactive in that condition ; and, lastly, 

 those which have no external development of 

 wings or legs, but remain as inactive ovate 

 pupae. This was the first step towards arranging 

 Insects upon a truly natural system ; since, as 

 Messrs. Kirby and Spence have justly ob- 

 served,* although the employment of the meta- 

 morphoses taken alone leads to an artificial 

 arrangement, it is of the greatest use in con- 

 nexion with characters taken from the perfect 

 Insect, in forming a natural system. Our 

 illustrious countryman Ray, in the beginning 



* Introd. to Entomol. vol. iv. p. 442. 



of the eighteenth century, followed the example 

 of Swammerdam in arranging Insects primarily 

 according to their metamorphoses ; and Lister, 

 in 1710, followed with a modification of Ray's 

 classification, after which nothing further was 

 proposed until Linnseus published the first edi- 

 tion of his Sy sterna Naturae in 1735. His arrange- 

 ment was based upon the form and structure of 

 the wings. By these he divided Insects into three 

 groups. First, those \vithfpur wings, in which 

 he included in three divisions those Insects 

 which now constitute his orders Coleoptera, 

 Hemiptera, Lepidoptera, Neuroptera, and Hy- 

 menoptera. In the second group he placed 

 Insects with two wings, his single order Dip- 

 tera ; and in the third, Insects without wings, 

 his order Aptera. In this arrangement, founded 

 partly upon that of Aristotle, Linnaeus was 

 particularly successful in establishing some very 

 natural series, although in including the Crus- 

 tacea among his Aptera, like Swammerdam 

 and Ray, he receded a little from a natural 

 system. After Linnaeus, Degeer and Geoffrey 

 each proposed a new arrangement, but it was 

 not until an entirely new set of organs had 

 been selected by Fabricius that Insects began 

 to be arranged upon truly natural principles. 

 The parts from which Fabricius drew his cha- 

 racters were those of the mouth, by which he 

 divided Insects primarily into two sections, the 

 Mandibulated, or those furnished with jaws for 

 comminuting their food, and the Haustellated, 

 or those which take their aliment by means of 

 a flexible elongated proboscis, without distinct 

 manducatory organs. But the difficulty of 

 forming a strictly natural system still existed, 

 so long as the characters employed were derived 

 only from particular sets of organs, and not 

 from a consideration of the whole. Cuvier, by 

 founding his arrangement upon an examination 

 of all the external organs, and thereby establish- 

 ing natural families, advanced very far towards 

 the object desired, and was followed by La- 

 treille, Lamarck, Dumeril, Leach, Kirby and 

 Spence, and MacLeay, who continued to im- 

 prove the arrangement of the class. These have 

 been followed by Messrs. Stephens and Curtis, 

 and very recently by Mr. \Vestwood, the inde- 

 fatigable Secretary of the Entomological Society, 

 each of whom has proposed a different arrange- 

 ment. But none of the systems hitherto pro- 

 posed are entirely satisfactory, so great indeed 

 is the difficulty of discovering the connecting 

 links of families, which, distributed over the 

 whole globe, are believed to include from 

 100,000 to 150,000 distinct species; and this 

 difficulty will probably continue until the in- 

 ternal as well as the external organization is 

 better known in a greater number of insects 

 than it is at present, and applied to their 

 arrangement, as has lately been done by Bur- 

 meister. In the succeeding pages we shall 

 adopt the arrangement of Mr. Stephens, giving 

 a synoptical view of the families, with the 

 addition of some of the recently established 

 foreign ones, and shall also add particular 

 descriptions of some of the most remarkable, 

 referring our readers for more minute descrip- 

 tions of them to Mr. Stephens's admirable 



