MESOGKAMMA. 25 



This striking species is readily recognizable from Bigot's description. The front and 

 middle tarsi are yellow at the base, and the hind pair is black ; the hind femora and 

 tibiae are in great part brownish. The face may wholly want the dark spot, and the 

 front of tbe female has no purple. The male vertical triangle is elongate and narrow, 

 shining purple behind. 



2. Mesogramma politum. 



Scava polita, Say, Journ. Acad. Phil. iii. p. 88 1 ; Complete Writings, ii. p. 77 \ 

 Syrphus politus, Say, Araer. Ent. i. t. 11. f. 8 3 ; Complete Writings, i. p. 24 4 ; Wiedem. Aussereur. 

 zweifl. Ins. ii. p. 132 \ 



Mesograpta polita, Willist. Synopsis N.-Am. Syrphidse, p. 98 6 ; Riley & Howard, Insect Life, i. 

 p. 4 7 . 



Syrphus cingulatulus, Macquart, Dipt. Exot. 4 e Suppl. p. 155 8 . 



Syrphus hecticus, Jsennicke, Neue exot. Dipt., in Abh. Senck. Ges. vi. p. 398 9 . 



Hab. United States 1 3 , Pennsylvania 5 , Connecticut 6 , Georgia 6 , North Carolina 6 , 

 Kansas 6 , Illinois 9 , Florida 8 . — Mexico, Acaguizotla 3500 feet, Amula 6000 feet, 

 Chilpancingo 4600 feet, Hacienda de la Imagen 4000 feet, Venta de Zopilote 2800 feet, 

 Tierra Colorada 2000 feet, and Dos Arroyos 1000 feet, all in Guerrero, Teapa in 

 Tabasco (H E. Smith), Temax in North Yucatan (Gaumer). — Cuba 6 



Seventy-five examples. They agree closely with specimens from the United States. 



3. Mesogramma marginatum. 



Scava marginata, Say, Journ. Acad. Phil. iii. p. 92 *; Complete Writings, ii. p. 80 2 . 

 Syrphus marginatus, Wiedem. Aussereur. zweifl. Ins. ii. p. 146 3 . 



Mesograpta marginata, O. Sacken, Cat. Dipt. 2nd ed. p. 125 4 ; Willist. Svnopsis N.-Am. Syrphid», 

 p. 100 5 . 



Syrphus quintius, Walker, Ins. Saunders., Dipt. p. 239 6 . 

 Mesograpta (?) circumdata, Bigot, Ann. Soc. Ent. Fr. 1884, p. 107 \ 



Hab. North America 1 3 6 , Atlantic, Southern, Middle, and Pacific States 5 , Atlantic 

 States and California 4 .— Mexico 7 , Amula 6000 feet, Omilteme 8000 feet, Chilpancingo 

 4600 feet, Mexico city, Cuernavaca in Morelos, Teapa in Tabasco (H. H. Smith), 

 Orizaba (H. H. Smith and F. I). Godman). 



Fifteen specimens. Three males have the scutellum black in its middle. The 

 vertical triangle is unusually large in this species. 



4. Mesogramma ? 



Male. Face, frontal triangle, and antennse yellow ; cheeks black. Vertical triangle large, broad, elongate, shining 

 purple. Mesonotum somewhat bluish or bronze-black, more shining towards the sides ; median line 

 whitish ; margins without yellow stripe ; a round spot on the humeri, and rarely an indistinct one on 

 the postalar callosities, yellow. Scutellum shining metallescent black, without yellow. Abdomen elon- 

 gate; first two segments shining black; the other segments brown and red, sometimes darker, sometimes 



biol. centr.-amek., Dipt, Vol. III., December 1891. e 



