COLEOPTERA. 



77 



above character we add, mouth with jaivs, all doubt 

 as to the admission of the hemiptera is removed. An 

 attentive comparison of the wings and wing covers, 

 Would unquestionably have led to the same result; 

 but that now mentioned is not only much more 

 simple and uniformly existent, but is also evidently 

 dependent upon much more important considerations 

 than the form of the wings and elytra. In like man- 

 ner the differences existing between the oral organs 

 of the coleoptera and the orthoptera might be resorted 

 to, but another and more important character is at 

 hand. Thus the orthoptera, in their passage to the 

 perfect state, undergo no other change than the 

 casting of the outer skin, and the gradual develop- 

 ment of organs of flight, whilst in the coleoptera the 

 metamorphosis is complete, and the pupa state quite 

 inactive. Hence by the addition of the character, 

 jutantorpkans, <> raihcr pupa, incomplete, we have three 

 leading characters, which will not only separate the 

 coleoptera from the fly, the butterfly, the cimex, &c., 

 but also from those insects which have been by some 

 authors united therewith. It is to be observed, how- 

 ever, that the first of the above characters does not 

 exist throughout the entire order ; thus in certain, 

 although few instances, both wings and elytra are 

 entirely wanting, as in the glow-worm and the female 

 drilus; in others the elytra, though existent, are 

 soldered together without any wings being concealed 

 by them, as in many of the Carabidce, Klapsidte, and 

 other terrestrial darkling beetles, which have no use for 

 wings. There are in like manner to be found ex- 

 ceptions to the transverse folding of the wings, in 

 the Buprestldce and some of the longicorn beetles, 

 whilst in Meloe one elytron partly laps over the 

 other, and in Sitaris, Rijnpliorus, &c., the suture is 

 not straight, the elytra not shutting together, whilst 

 in Atrctctocerus, Molorchm, &c., the wings are not 

 covered by the wing covers, from the reduced size 

 of the latter. Still there are sufficiently strong indi- 

 cations of direct affinity between all these insects, 

 and others belonging strictly to the order, so that it 

 is impossible not to perceive that they equally belong 

 to it, although -they form exceptions to one out of 

 several of its leading characters. 



Scarcely any branch of natural history has been so 

 much investigated as this order of insects ; indeed 

 many students, as well as amateurs, have exclusively 

 devoted themselves to this group. The amazing 

 variety of form ; the richness or agreeable disposition 

 in their colours ; the great number of modifications 

 which their external organisation presents to our 

 view, and which consequently afford so many addi- 

 tional aids towards their classification; the circum- 

 stance that these animals generally surpass in size 

 the remainder of the class to which they belong, and 

 the ease with which they are preserved, owing to the 

 greater consistence of the outer covering, all tend to 

 render the coleoptera interesting to the student ; but 

 to these circumstances may be added the vast extent 

 as regards the number of species contained in the 

 order. It would, indeed, be difficult correctly to 

 judge of the number of these insects, distributed over 

 the surface of the globe, each arrival from foreign 

 climes bringing hosts of novelties to our cabinets 

 and not only is it from the little frequented countries 

 either of the old or new world that these importations 

 arc derived, but every year adds considerably to the 

 lists of our indigenous species, by the discovery o: 

 umlcscribed beetles. Many persons have hence been 



nduced to believe, that a new creation was constantly 

 *oing forward, or that from the admixture of species, 

 ivbrids were produced. The latter is a difficult 

 question to solve, but analogy, derived from well 

 authenticated and long known species, induce us to 

 object to such an idea. In order to account for this 

 ntroduction of novelties, it is to be noticed, not only 

 that the number of actual collectors of insects is 

 wonderfully increased, as well as the modes of col- 

 lecting greatly improved ; moreover, in all our large 

 maritime and commercial towns, the productions of 

 foreign climes are to be found in great abundance, 

 and with them are evidently introduced an immense 

 number of wood, plant, or grain-feeding insects, which 

 in favourable circumstances multiply and become 

 acclimated amongst us ; hence it happens that the 

 vicinity of large towns exhibits a richer list of species 

 than more thinly peopled districts. 



It is however unquestionable, that the coleoptera 

 exceeds in point of number of species, any other 

 order of insects, although the diptera and hymen- 

 optera, now that more attention is being bestowed 

 upon the minute species, are not far behind the 

 beetles in point of numbers. The French collections 

 are estimated to contain not fewer than 30,000 dis- 

 tinct species of coleoptera, and it is by no means 

 improbable that at least '20,000 more are contained 

 in the cabinets of other countries, wanting in the 

 former. Thus 50,000 species may be considered as 

 actually existing in our collections ; and when it is 

 known that immense tracts of country in Asia, Africa, 

 North and South America, New Holland, and the 

 Islands of the Southern ocean exist, from which not 

 a single insect has been received, we may without 

 exaggeration conclude that there are from 100,000 

 to 150,000 species of beetles in existence. This 

 number, however, will scarcely be considered over- 

 rated, when it is further mentioned that in our own 

 little island upwards of 3,500 native species have 

 been actually described. 



In the series of insects the coleoptera also seem 

 to possess a certain degree of superiority, which 

 places them in the foremost ranks of the class to 

 which they belong. An eminent French naturalist, 

 M. Marcel de Serres, has not indeed adopted this 

 opinion ; the orthoptera, whose anatomy he has pro- 

 foundly investigated, being in his ideas entitled to be 

 placed at the head of the class, his opinion being 

 founded upon a consideration of the superior develop- 

 ment of the locomotive organs. Latreille however 

 has considered that too much weight has been given 

 to this character, and has suggested, from a general 

 consideration of their comparative anatomy, that the 

 coleoptera are the most perfectly organised of insects, 

 and consequently as being entitled to the highest 

 rank. 



We will now proceed to give a rapid sketch of the 

 external anatomy of these insects. The body consists 

 of the head, a large segment which has been generally 

 termed the thorax, two short inconspicuous segments 

 which support the wing covers and wings, and the 

 two posterior pairs of legs, and which form a portion 

 of the true thorax ; and lastly, a continuous series of 

 rings which compose the abdomen, and which are 

 not furnished with locomotive organs. The head is 

 generally of a rounded form, furnished with a pair of 

 antennre, extremely varied in their form in the differ- 

 ent familes, but which in the majority consist of only 

 eleven articulations; they often differ in the sexes. 



