NATURAL SCIENCES OF PHILADELPHIA. 201 



will be identified afterwards with European ones. The question of the real or 

 apparent identity of American species with European ones, especially among 

 insects, is a very delicate one, and requires a special investigation. Until some 

 general principles are adopted in this respect, entomologists will have to depend 

 on approximation, and their decisions will always be more or less arbitrary. 

 In any event there is very little harm done in describing under a new name a 

 European species found on this continent. The important point is, to have it 

 well described, and if such is the case, its affinity or identity with the European 

 species will easily be found out afterwards. 



The terminology of the neuration of the wing, as explained on the diagram, 

 is for the most part that of Walker. I have introduced some changes, where I 

 could not follow him, as well as additions, where my purpose required it (es- 

 pecially some new names of the cross-veins). My terminology is in many points 

 perfectly arbitrary, but until a rational nomenclature of the neuration of the 

 wings, applicable to all families of D i p t e r a , is adopted, the monographer of 

 every family will be compelled to invent his own. There is no great harm in 

 this, if only the meaning of the terms is clearly explained. 



The terminology of the other parts of the body required almost no changes ; 

 there was only the thoracic portion between the suture and the scutelium, which 

 had no peculiar name in the former descriptions. I call it scutum of the meso- 

 thoraz, or simply scutum, following in this the nomenclature expounded by 

 Westwood in Griffith's Animal Kingdom, vol. xv. p. 722, tab. cxxii. Ac- 

 cording to the same authority, I call prezscutum of the mesothoraz, or sim- 

 ply prcescutum, the upper thoracic portion between the collare and the su- 

 ture. 



Not having been able to give figures of the wings of the different species, I 

 have supplied their place by frequent references to the plates in Meigen's, 

 Schummel's* and Walker's works, as well as by descriptions of the neura- 

 tion. 



The circumstance that the genital organs of the male L im no b i ae can be 

 drawn from living specimens only, prevented me from replacing my hand by 

 that of a more skilful draughtsman. I appeal, therefore, to the indulgence of 

 my colleagues in Dipterology. 



My friend Dr. John L. Le Conte has kindly volunteered to correct the proofs 

 of this paper, which will be published during my absence, and I tender him my 

 most cordial thanks for this mark of friendship. 



Explanation of the terminology of the wing, as used in this paper. 

 Arem and Areolets. 



1. Subaxillary area. 9. Second radial area. 



2. Axillary area. 10. Cubital area. 



3. Anal area. 11. Subapical area. 



4. Pobrachial area. 12. First externomedial, or petiolate areolet. 



5. Praebrachial area. 13. Second externomedial areolet. 



6. Mediastinal area. 14. Third externomedial areolet. 



7. Subcostal area. 15. Fourth externomedial areolet. 



8. First radial area. 16. Discal externomedial areolet. 



The areolets from 9 to 15 have been sometimes called collectively apical 

 areolets. 



*Beitrage zur Entomologie, besonders in Bezug auf Schlesien, von T. E. Schummel and 

 Herm. Stannius ; 8vo. Breslau, 1832. 



Among other papers, this collection contains a monograph of theSilesian L imnobiae, 

 by Schummel. 



1859.] 



