348 Professor Williston on the 



Numerous specimens. The most northern habitat so 

 far given for this species is Nebraska, by Hunter ; the 

 most southern one, Buenos Aires, by Lynch (Dipt. 

 Argentina, 8yrphida3, 47). It is probably at home in all 

 the intervening regions, as well as the adjoining islands. 



OCYPTAMUS. 



1. Ocyptamus dimidiatus. 



Syrphus dimidiatus, Fabricius, Spec. Ins., ii., 484; 



Ent. Syst., 310; Wiedemann, Auss. Zw. Ins., ii., 



140. 

 Scaeva dimidiaia, Fabricius, Syst. Antl., 254. 

 Cheilosia dimidiata, Macquart, Dipt. Exot., ii., 2, 105. 

 Pipiza dolosa, Walker, Trans. Ent. Soc. New Ser., iv., 



156 (Austen). 

 Pipiza divisa, Walker, 1. c. (Austen). 

 Ocyptamus dimidiatus, Schiner, Nov. Exped., 346 ; 



Wulp, Tijdschr., v., Ent. xxvi., 10 ; Williston, Biol. 



Centr.-Amer. Dipt., iii., 30 ; Giglio-Tos, Ditt. del 



Messic, ii., 53 ; Austen, Proc. Zool. Soc. Lond., 



1893, 134. 

 Baccha dimidiata, Williston, Synopsis N. A. Syrphida3, 



120, pi. v., fig. 10. 



Hab. Central and South America, and the West Indies. 



Allograpta, 

 Osten Sacken,Bull. Buflf. Soc. Nat. Sc, iii., 40, 1876. 



1. Allogvapla exotica. 



Allograpta exotica, Wulp [nee Wiedemann), Tijdschr., 

 v., Ent., xxvi., 2, pi. i., fig. 2, Guadeloupe. 



A single female specimen, agreeing fully with the 

 description of what Wulp thought was Weidemann's 

 Syrphus exoticus. In the Biologia Centr.-Amer. I con- 

 sidered Wulp's species doubtfully identical with A.fracta, 

 O. S. Osten Sacken^s species, however, does not have 

 the scutellum broadly black, as did the specimens Wulp 

 described, and as does the specimen from St. Vincent 

 now before me. Wiedemann does not mention the spot 

 on the scutellum, and I doubt very much that it was pre- 



