24 



pose in the Lepidoptera, Hyinenoptera, as well as the Hemiptera, Orthoptera, 

 and Neuroptera. Hitherto the pieces composing each of the thoracic lines 



have been used with the greatest success in the Coleoptera by Dr. J. I.. Le 

 Conte, in his winks on Ninth American Coleoptera.* 



Various hymenopterists have found the thoracic characters very useful 

 in classification. 



in the Lepidoptera the writerf lias found that good family (diameters 

 exist in the relative size and proportion of parts in the thorax as well as 

 the head. 



The Zi/irnhltc and Noctuidce% have been found to differ in apparently reli- 

 able thoracic characters. The Phalanidce also differ from the other lepidop- 

 terous families in the form of the thorax. In order to bring out these differ- 

 ences, 1 have on plate 7 represented the dorsal and lateral aspect of the thorax 

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

 seize upon the differential characters without long verbal descriptions. 



The terminology of parts is as given in my "Guide to the Study of In- 

 sects - ', which was adopted from the works of Audoum§ in connection with 

 those of Fabricius, Kirby and Spencc, Burmeister, Newport, and others. 

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

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

 Study of Insects'', which could not be 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 Lepidoptera, beginning witli the 

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



Pteroplio/ida' [Pterophorus marginidactylus Fitch, pi. 7, fig. 9, da). Ter- 

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

 than usual in the other families, unless we except the Hepiali among the Dom- 

 bycidie. The mesoscutum is very small, squarish; mesoscutellura very large 

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

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



* Classification of the Carabidtz of the United States. Transactions of the American Philosophical 

 Society, vol. x, lfc'53. On the Systematic Value of Ehynchophorous Coleoptera. American Journal of 

 Sciences and Ails, vol. xliv. .Inly. 1867. Classification of the Coleoptera of North Ameiica. Miscellaneous 

 Collections, Smithsouian Institution. 



i Notes on the Family Zygwnidai. Proceedings of the Essex Institute, April. 1864. 



! Characters of the Noctuidce. Proceedings of the Portland Society of Natural History. 



<Si L'Auatoinie comparative des Parties solides des Insects. (Ann. pen. ties Se. Phys., 1820, torn. 7). 

 1,'eclierelies anatomiqaes sur lo Thorax des Animanx articules et colui des lloxapodes en particular. 

 Acad. Sc, 1820. 



