1SS2.] ■^"'♦' [Willistoii. 



Sj'rphidae, by Dr. S. W. AVillist' ii,'' was presented through, tlic 

 Secretary, with a letter from the autlior, dated New Haven, 

 Yale College Museum, May 12, 1882. 



" The Classification of the Ungulate Mammalia " Avas read bj- 

 Prof Cope. 



New nominations, Nos. 959, 960, 961, were read. 



TIip, President reported that he had forwarded a memorial 



ERRATUM. 



Pai?e 474, line 24, after JJeles, insert Helicfis. 



Page 474, line 25, omit IleUctis. 



Page 474, line 27 ; remove ^muropoda and Ilymnarctos from ^lu- 

 RiD^, and insert under Uhsid^ (line 28) the names ^luropoda and 

 Myceiturctos. 



Page 475, foot-note, for vig. rend Vi«-. 



— t » 



classify. Although composed throiighout the world of about one uuuarea 

 and forty described genera, they present no characters that will decisive!}^ 

 distinguish any considerable number. As a natural result, many genera 

 have been loosely formed and more loosely described, until the difficulty 

 in identifying species without the aid of numerous types has become ex- 

 tremely great. The present paper is the result of many hours tedious 

 labor in identifying a considerably large amount of material wholly with- 

 out the aid of types. Prepared two or three years ago it has been re- 

 written and changed many times ; that it is free from error j^et I do not 

 presume to hope, but from my own experience in the difficulties that are 

 met with in working with the aid of books alone, I believe that it will 

 materially aid in the study of our species. 



In Osten Sacken's catalogue of American Diptcra — a work itidispensable 

 to all entomologists — fifty-seven genera are recorded as having been cred- 

 itably recognized from North America. Toxomerus of Macquart I have 



PROC. AMER. PUILOS. SOC. XX. 112. 2r,. PRIXTED AX^GUST 3, 1882. 



