THORAX. 261 



be applied. This has been especially the case with the 

 thoracic segments of insects ; and it is only within a very 

 few years that entomologists have given any extended atten- 

 tion to this part of the subject, or have endeavoured to 

 introduce a fixed series of names. Audouin, Kirby and 

 Spence, MacLeay, and Burmeister, have especially laboiu-ed 

 in this field, in which much still remains to be effected. 

 Linnaeus thus described this part of the body, which he 

 called the trunk: — " Truncus, inter caput et abdomen, 

 pedatus, thorace, supra dorso, postea scutello, subtus pectore 

 sternoque." In his descriptions, however, he applies the 

 term thorax either to the large shield which covers the first 

 thoracic segment in beetles, or to the entire trunk, as in the 

 Hymenoptera. This mode of description was, notwithstand- 

 ing its evident impropriety and want of precision, adopted 

 by most entomologists. Ilhger endeavoured to correct this 

 nomenclature by giving to the trunk of Linnaeus the term 

 thorax, designating its upper part thorax superior, and its 

 lower sm-face thorax inferior. Latreille and others divided 

 this part of the body into three distinct sections, the two 

 posterior of which, from bearing the wings, Chabrier united 

 under the name tronc alifere, which Kirby and Spence 

 adopted, naming those two segments alitrunk ; and the first 

 segment, which bears the fore legs, which these authors 

 rather regard as arms or hands, manitrunk. This nomen- 

 clature has not, however, been adopted, although Strauss- 

 Diirckheim adopts this division of the thorax, calhng the 

 first segment corselet, and the two others the thorax. Most 

 of these authors, however, regard the three segments follow- 

 ing the head as sufficiently separate to require separate 

 names ; and the terms prothorax, mesothorax, and meta- 

 thorax, originally proposed by Nitzsch, have been apphed to 

 them. Indeed, Audouin, MacLeay, and Burmeister, regard 

 them as segments of equal rank, but as conjointly uniting to 

 form the thorax; whilst Kirby and Spence employ these 



