ENTOMOLOGY. 



431 



Hence will be seen the necessity for studying col- 

 lections of animals, and particularly of insects, in the 

 mass ; for though the knowledge of species, as Mr. 

 Kirby has well observed, is indispensable for the 

 registry oi" facts and other practical purposes, yet the 

 knowledge of groups leads to a higher wisdom ; and 

 indeed it is through these that webe?t descend to the 

 study of species. The first tiling, therefore, requisite 

 is, to ascertain to what order of insects any individual 

 specimen may belong. For this purpose an inspection 

 of the mouth (for the purpose of ascertaining whether 

 it is furnished with jaws or with a sucker), and of the 

 structure of the wings, will generally suffice. The 

 next step is the separation of your collection into the 

 primary sections and families of which the orders are 

 composed ; and here, of course, the characters will 

 vary in thediilereut orders, for instance, in the order 

 of beetles (Coleoptcra}, the primary sections are 

 founded upon the variation in the number of joints 

 in the tarsi (or last articulated part of the leg) ; 

 whereas in the two-winged flies (Diptera) this charac- 

 ter is constant, and the number of joints in the 

 antennae constitute the leading characters of the pri- 

 mary divisions. For the families no better rule could 

 be laid down than to study the characters of the 

 Liniuean genera, which in fact correspond generally 

 with the modem families of insects ; but as we have 

 already stated in several of our entomological 

 articles, the contents of these groups have so im- 

 mensely increased since the days of Linnaeus, that 

 it has become necessary to subdivide them into minor 

 divisions, to which the names of genera and sub- 

 genera have been given ; and here it will be necessary 

 to have recourse to such authors as Fabricius and 

 Latreille, Stephens, or Curtis, for obtaining- an idea of 

 the extent to which these subdivisions have been 

 carried, as well as for obtaining a knowledge of the 

 various subdivisions themselves. The practised eye, 

 indeed, can readily reduce an extensive family of 

 insects into its sectional groups without any other 

 assistance than that derived from long experience, 

 because the most nearly allied species possess such 

 a general resemblance to each other, that it is almost 

 impossible to overlook their relationship ; for instance 

 the restricted genus Carabns comprises a very exten- 

 sive series of ground-beetles, varying but little in size 

 (compared with the variations in size which occur ir 

 the family), being moderately large, and ornamented 

 more or less with metallic tints ; so also among but- 

 terflies, the genus Colias comprises species being 

 generally of a brimstone colour. We now arrive ai 

 the investigation of the specific name of the jnsecf 

 under examination, and here lies a great difficulty 

 owing in general to the number of species; grea 

 relief, however, is afforded by the introduction of sub 

 divisions in the longer genera, by which we arrive 

 almost immediately at the name of the species itself 

 In general the descriptions of insects are written ii 

 Latin, or at least, if an author chooses to give a 

 specific description in his native tongue, it seems by 

 common consent and usage to be required that he 

 should commence his descriptions by a short Lath 

 cnaracter.which.from the almost universal employ men 

 of that language in works of natural history, is intel 

 ligible to naturalists throughout the world. More 

 over, the indication of the natural length and expansio_ 

 of an insect, the addition of the country which i 

 inhabits, and the references to the works of othe 

 authors by whom the species may have been described 



nd especially where it has been figured, all tend to 

 ender this branch of the science less intricate than it 

 t first appears. If, however, after all research into 

 le works of those authors who have especially 

 evoted their attention to the family or genus of 

 isects, to which the one under examination belongs, 

 ; should be evident that it is a nondescript, its 

 escription, embodying the points of distinction 

 vhich it presents with reference to the already 

 escribed species, and whether resulting from struc- 

 ural variation, or from differences of colour, or of 

 tiiation or puncturation (as in the beetles), may be 

 attempted, taking as models the specific descriptions 

 ontained in such admirable monographs as those of 

 Mr. Kirby upon the English bees, or the genus 

 4pion, or that of Latreille upon the ants. 



But the investigation of species, although valuable 

 or the sake of precision in the identity of the object 

 A'hich is the subject of observation, is by no means 

 ssential for enabling us to study the structure or 

 economy of an insect, and this brings to our notice 

 everal other classes of entomologists, who more 

 ispecially merit the title of philosophical observers 

 of nature. Of these the out-door naturalist first 

 claims our attention. Instead of running from one 

 end of the country to the other, climbing mountains 

 and descending valleys, stopping only so long as may 

 >e necessary to transfix the luckless objects of his 

 chase, and deeming himself happy only when his 

 collecting box is filled with specimens, the real ob- 

 server of nature finds materials for study even at his 

 own door. The former, it is true, meets with many 

 rarities, and even perhaps nondescript species, but 

 notwithstanding all his toil, has he observed a single 

 "act relative to the history and economy of a single 

 insect? Swammerdam and Reaumur toiled not thu?, 

 and yet their labours are read even now by all the 

 world, whereas the labours of the collector are but at 

 best sellish, and the descriptions of his new species 

 read only by a few amateur collectors like himself. 



Seek then a spot favourable for the habitations of 

 insects a sunny nook in a wood, a hot sandbank, or 

 the margin of a stream, and watch the proceedings 

 of the numberless insects which frequent these spots. 



Examine, for instance, the clear water, and watch 

 the movements of the various aquatic insects with 

 which it abounds ; and especially observe the silvery 

 silky globe which the diving water-spider bears about 

 with it, and in which, in an enlarged form, it passes the 

 winter. Observe the mode in which the insect, 



Diving: water spider, in its diving bell, fixed to plants at the 

 bottom of the water. 



rcstin"- upon a flower, extracts the honey from its 

 cup- trace the flight of that sand wasp, and notice the 

 peculiarities of its manoeuvres in the construction of 

 its burrow ; examine with careful eye the movements 

 of that sawfly in the act of forming a channel in the 

 sprig in which to deposit its eggs ; or listen to the 



