INSECTS. 



meloIonthE, Tabr.) ; others have them fimply ciliated (the 

 ectoniae), or in the form of a pencil (thelucani.) 



The fame variations take place in the lips and palpi, and 

 are not merely obferved between the different genera. For, 

 although great pains have been taken to fubdivide this fa- 

 mily into numerous genera, none of thefe arrangements are 

 founded on a perfectly fimilar conformation of the mouth. 



fmall Infefts which come within reach. "Wlien the libelluU 



has its wings, it no longer needs fuch an artifice : its lip is 

 fliortened, and confined to the ordinary funftiohs. 



The larvas of the hymenoptera have very fimple organs 

 of maftication, confiding principally of Imall, ihort, and 

 ftrong mandibles. The mouth of the larvae of the coleop- 

 tera has the fame parts as that of the infefts ; but they 



Nothing can prove more clearly the imprafticability of the are differently fiiaped. Thus the lucani, which in the per- 



fedt ftate have fuch enormous mandibles, and fuch peculiar 

 pencil-fliaped maxillx, have, while larvae, a nearly orbicular 

 upper lip, immediately articulated with the front ; ftiort, 

 ftrong, thick, pointed mandibles, {lightly arched externally 

 and on the inner fide ; towards their loofe extremities they 

 have three denticulations on one plane, and towards their 

 bafes a ftriated and plr.ne molar furface : it is plain that 

 thefe are in their mouth inftruments for cutting and chew- 

 ing wood. The maxillffi are terminated by two fmall hooks. 

 The different configurations of the palpi, of the homy of wliich one is moveable, a very fingular ftruAure, and 



and membranous portions of the tongue, of the maxil- fupport a feeler of four articulations. The lower lip is 



1-<E, &c. have been carefully defcribed by naturalifts : but broad, and in a manner truncated, and has two palpi ; each 



their labours have not hitherto furnifhed any general remarks compofed of two pieces. 



which fuit our prefent purpofc. The fcarabaei differ remarkably from the lucani in their 



project, fo refolutely perfifted in for thirty years by M. 

 Fabricius, of eftablifhing a method of infe6ology on the 

 conformation of the mouth only. 



A third natural family of the coleoptera, that of the 

 roflricornia, is charafterizcd by having its mouth at the end of 

 a long fnout. Such of the others as are well deterniined, 

 for example, the herbivora, th.e lignivora, S:c. have no link- 

 ing charafter common to all the genera, although there is a 

 certain refemblance. 



Jthly. In the Orihoptera. — This order is very uniform in 

 the ftruciure of the mouth ; it poffeffes always ftrong 

 mandibles and maxills, under which is the lower lip. A 

 moveable upper lip covers the mandibles more or lefs com- 

 pletely. The maxillse are flrongly denticulated, and have 

 always an articulated feeler, and another not articulated, 

 which fometimes grows fo broad as to cover and proteft 

 the maxillse, whence it has been called galea : but often it 



mouth ; but the two genera agree almoil entirely 

 mouths of the larvae ; the fame obfervation may be made of 

 the melolonthx and cetoniaj, which are alfo very different 

 from each other. 



This fmall moveable hook may be confidcred as a fecond 

 maxillary feeler ; thefe larvae would then have fix, while 

 their perfeft iufefts have only four. We mull obferve 

 ilfo, tliat the larvse, both of the lucani and of the fcarabsi. 



IS as flender as a thread. The lower lip has alivays tivo have two ftrong teeth on the upper furface of the lower hp 



articulated palpi, between which is a more or Icfs divided near the pharynx. 



tongue. The pharynx opens upon the tongue, as in the The prioni (Fabr.) which have elongated mandibles hke 



coleoptera, not under, as in the hymenoptera ; fo that thefe the lucani, have nothing of this kind in the larva ftate. 



infeSs are true mafticators : the principal differences of There is a very large upper hp, lobated, rounded, villous, 



the genera are founded on the ilivifion of the part called fupported by a membranous lamina, then two ftrong, curved, 



the tongue, and on the equality or inequality of the por- cutting mandibles, furniftied at their bafes with two coni- 



tions. Thus, in the mantis there are four, pointed and cal palpi, of which the rings enter one into tiie other, 



equal: in the phafma the two middle ones are much tiie like the tubes of a telefcope, and which are probably the 



Ihorteft. The achetas, locuftae, and acridia of Fabricius, rudiments of antennas. A foft mafs, confifting of three 



have the two outer ones broad and rounded ; and the in- lobes placed behind the mandibles, reprefents, by its middle 



termediate one fhort and pointed. The biatts and the lobe, tie lower lip with two very fhort rudiments of labial 



forficulvB have two oblong ones; the truxalides (Fabr.) palpi, and, by each of the lateral lobes, the maxillae pro- 



the gryllj, and the pneumora;, have only two rounded ones, &c. perly fo called with its proper palpi, compofed of four 



6liily In the Lar-oss of InfeSs. — Thefe organs are not dif- 

 tributed in the larvse, as in the perfeft infefts : many larvas 

 with jaws produce perfeft infefts, which have none, fuch 

 are all tiiofe of the papihos, and feveral of the diptera. 

 Different larvse have often fimilar jaws when the infefts pro- 

 duced from them have very different ones ; as in the whole 

 family of the lamellicornia. 



conical articulations, of which the lalt is the fmalleft. 



On the contrary, the dytifci, which have very flightly 

 prominent mandibles, have them very long in the larva rtate. 

 They reprefcnt two ftiarp hooks, perforated at the extremi- 

 ties, which ferve for fucking. There are no vifible maxilla;, 

 but merely two long filiform palpi of five pieces ; while the 

 perfect infeft has four maxillary palpi. This is exactly the 



- The larva: of infrfts which go through an incomplete reverfe of what we have juft feen in the lamellicornia. In- 

 metamorpbofts, have the fame kind of mouth as the perfeft ftead of the lower lip there are two tubercles, each of v.hich 



infefts, with the exception of fome modifications in thi 

 proportions of partes ; thus the mouth of all the orthop- 

 tera is the fame in the three ttates. The change of pro- 

 portions jui.1 mentioned produces the moft fenfible effefts in 

 the neuroptera odonata or the libellula;. Tlicir mandibles 

 and maxiilas are the fame in the larva as in the perfeft ftate. 



fupports a feeler of two pieces. The larva of the hydro- 

 philus alfo wants the maxilla, but has four palpi ; the man- 

 dibles are Ihort, cutting, and not perforated. 



Of all larvae, thofe of the lepidoptera differ the moft 

 widely from the perfeft infefts in relpett to the mouth ; 

 and, what is ver)' fingular, their mouth is conftruftcd 



Their lower lip prefents alfo the fame divifions, but it is the plan of that in infefts with jaws, although it poffeffes 



plaecd on a very long pedicle, with an angular turn or no trace of thefe parts in the butterflies. Under a femi-or- 



elbow in its middle, fo that it remains commonly in its na- bicular upper lip, and under two ftrong, cutting, denticu- 



turai poiition under the maxilla, but the animal can, by iated maxilUe, are three tubercles reprefcnting the lower lip 



iiraightpqiijg the curved pedicle, carry it fuddenlyconfiderably and the maxilhx ; the latter feem compofed of pieces, which 



forwards ; and, as the notches which terminate it will ferve enter more or lefs one into the other, and terminate by 



tliL- purpoli; of pincers, they are employed for fcizing the two fmall tubercles, of which the internal, armed with two 



Itut 



