24 



posL' ill till- i.rpidoptcra, ll_viiiciii)|il('r;i, as well as (he llciui|i(cra, OrtliDiilcra, 

 and Xt.'uroptcra. Hitherto tlie pieces coiiiiKisiug eaeh of the tiioracic rings 

 have been used with tlu' greatest success in tlie Coleopiera l)y Ur. J. L. Lc 

 Contc, in Iiis works on North American Colcoptera.* 



Various hyuienophn-ists have I'ound th*^ thoracic characters very useful 

 in chissification. 



In the Le|)i(h)p(era the writerf has found that good fuiiily characters 

 exist in the relative size and [)r()[)ortion of parts in the thorax as well as 

 the liyad. 



Tlie Zijatnkhe and Noctiiida'X have lieen found to dilfer in appai-eiitly reli- 

 alile thoracic characters. The Vhalmnidtc also dilfer from the other h'pidop- 

 teroiis families in the form of tlie thorax. In order to bring out these dill'cr- 

 ences, I have on plate 7 represented the dorsal and lateral aspect of the thorax 

 in a typical species of each Icpidopterous family, so that the eye may at once 

 seize upon the diiferential characters vvithout long verbal descriptions. 



The terminology of [)arts is as given in my "Guide to the »Study of In- 

 sects"', which was ado])ted from the works of Andoum^ in connection with 

 those of Fabricius, Kirl)y and Si)ence, Burmeister, Xewport, and others. 

 Without at this time revising the nouKMiclature of the external anatomy of 

 the thorax of Lepidoptera, further than I have done in my "Guide to the 

 Study of In.sccts", which could not l)e accomplished without extended study 

 of all the other orders of insects, I will briefly call attention to the most appa- 

 rent differences between the families of Lepi<lo[)tcra, beginning with the 

 lowest. The terminology is given in the explanation of the plates. 



FlcropJioiidcp {Pteropliorus marginidiictijlus Fitch, pi. 7, tig. 9, 'Jc/) Ter- 

 gum. — There is a greater equality in the size of the meso- and meta-thorax 

 than usual in the other tlunilies, unless we except the Hepkdl among the Bom- 

 hijcidie. The mesoscutum is very small, sipiarish ; me.-soscutclhim very large 

 and long, the sides equal; in extent, it is about one-lialf as large as the scu- 

 tum ; metascutum with the two halves remarkably large and broad ; scutel- 



* Classification of the Carabidw of tho IJTiited States. Transactions of the American Philosophical 

 Society, vol. x, l~b'.\. On the Systematic Value of Khynchoiihoroiis Coleoptera. Anicrican Jonrnal of 

 Sciences and Arts, vol. xliv, .Inly, lH(i7. Classitication of the Colcoptera of North Anieiica. Miseellaueons 

 Collections, Smithsonian In.stitntion. 



t Notes on th(^ Family Ziiiiaiiidir. Proceedinj^s of the P.sscx Tnstitntc, .\pril, IStU. 



t Characters of the Noctnid;e. I'rocecdings of the Portland Society of N'atnral History. 



vS L'Anatcnnie comparative dcs Parties solides des Insects. (Ann. gcu. des Sc. Phys., isao, torn. 7). 

 lleeherclies anatomifpies siir lo Thorax des Animau.x articules ct celui des llexapodos en parliculier. 

 Acad. Sc, l&'O. 



