10 KESCRIPTION or PAKTh. 



Spiu«ct: fltura au»l priifilmrn; tlu- l«itt»r Miplx'tl-* the haltcrts or poUers in di]>(en'U8 in- 

 Mctj. The tlii>nii Invariably Mi|>ji<'rts ."kix l«-g>. Thi> wingK iirv itumvUnum wanting, when 

 tho in-cTt \i Mid to Iteapterout : tlvjfc with two wing<i <uv dipterous; an«l ihow with futir, 

 Ittrapttrout, The »uiK"rl«>r wiui;ii are iirovidiil with an nrtirtilaling K>ck»-t, which l» formed 

 in jiart !•)• the orgiin tnlle*! the scapula : they lii* cl<»se ui>on the sternum ; they coiutitule 

 the vcoud i«ri|icijHiI |M>rtiun of the me<tothorax, l\lng one on each sUk- in front. Another 

 dittiuet jxirlionof the nieoothomx is the nusoilrrnum : it lies UjK.n the under Mde,o|>|>u»ltc 

 the me'-.notum ; in it-* urea the middle U%s ore artieulat*-*!. The im-v-Mernnm is not e<]ual- 

 ly deVeloiKtl in all onlers of jn^'clH : it it most ji-rfect in the Cole«»i>tem and Orthoptj-ra ; 

 the dorsal i>orlion has rfceivwl the nnme i>{ metanolum, quudrangular in form, and emargi- 

 aate in fn>nt. 



The i>art9 supixtrttnl by the thorax are the w ings and legs ; and, as has liecn ob«erved 

 already, the latter are inviiriably six in numl>er,and never nnntine- The wings are variable 

 in numlter, in form and in substance ; ami ujn'U the vuriui>ility in form and substance, the 

 orders are comi>os«-d. Thus those with four wings are ternK<l Irtrapleroui; those with two, 

 dipterous; and those with none, n/j/r roi/j. Tlie anterior pair inTetraptera is attachiil to the 

 mesothorox : this pair is also sometimes called the sujH-rior i«air, while the j-air attached 

 to the metathorax is ciUled the posterior or inJerit-r pair. The pair whirl. i« wnitiiiL- m ilip 

 Diptera, Is the posterior jmlr. 



It has lK>»n Slid tlwit tlie wings differ in form and substance. Nature M'W<m r. irt'irMs 

 rigonmslv the symmetry of parts. In Colts.ptera, the anterior wings differ from the i¥>sterior 

 both In substance and form. Tlie sui>stancf of the first is l<ath»r>-. nmn- or ]vs ricirl. and 

 horny : their form is various, but n<lai>ted to the dorsum or Kick of the insect ; while the 

 posterior are membranous, flexible and elastic, and cai)able of U-ing fol.Ic»l ixneath the 

 anterior wings. In another onlcr of Tetraptcra the wings are similar in form ami sul>stanre, 

 and of equal size : these Insects have received the name of Xcuroptcra. Where, howrerer, 

 In tetrapteroijs insects, the i»«isterior wines differ in size, but i)re.«erve the form and stib- 

 gtance of the anterior, the order is called llymmopteia. Kxamplea of Neumptera are the 

 tiragon flies ; of Hymenopteni, the common honey-b«T, wasp, etc. In flichf, the ricid an- 

 terior winn of the C ihs'ptcra Is of little u«4« : it s<-rves to protect the membranous wing 

 and aUlomen when nt rest. Hence it i< that the flight of U-otles is short, and sustained 

 evidently with much nv-re luU-r than that of dragon-flies or honey-lxes. The insects wh<>$« 

 wings are foAr,and covered with scales, an- callcil from this last circumstance I^pidoptera. 



It is j.roper here to remark, that while there is a great «lissimilarity U-tween the anterior 

 wing of B iHH'tle and that of a dragon-fly, jet we are not to supi>ose that the difl"erence Is 

 effected by a sudden b-ip : there is really a gradation in substance. We have insects whose 

 anterior wings are intermediate in this resj«ect, Inith in substance ami f -rm. Tims the Sim- 

 mon gra»shopp« r has an anterior wing which Is Utween le-ithrry an<l membranous, and Is 



