98 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



'■^ Hahitat. — Sauta Monica, California, Febrnary 20, 1876. A single 

 male." 



The chief differences that this description shows from A. obliqua are 

 in the black stripe on the face, and the first abdominal segment being 

 black. 



MESOGRAPTA. 



Toxomerus Macquart, Dipt. Exot., 5e SuppL, 92, 1855. 

 Menogramma Loew, Centur., vi, 47, 1865. 

 Mesograpta Loew, Ceutur., vol. ii, p. 290, 1872. 



Small, somewhat elongate species, thinly pilose, shining black, with 

 yellow markings on head, thorax, and abdomen. Head hemispher- 

 ical, face small, short, prominent in the middle. AntennsB situated 

 near the middle of the head in profile, short, third joint oral, arista 

 basal, bare. Eyes narrowly contiguous in the male, midway between 

 the antennae and ocelli; vertical triangle long, acute; front in female 

 longer than the face, narrowed toward the vertex. Ocelli in both sexes 

 remote from the vertex. Dorsum of thorax with a median cinereous 

 linear stripe and lateral yellow margins. Scutellum black, with yellow 

 border. Legs rather slender ; hind femora in the male sometimes 

 thickened and arcuate. Wings as in Syrphus. Type of genus, M. par- 

 vula Loew, North America. 



The species are very variable in the coloring of the abdomen, and cau- 

 tion should be used in founding new species on such differences. In- 

 deed here, as elsewhere in this family, specific characters are usually 

 more or less doubtful when not based upon some structural differences. 



TABLE OF SPECIES. 



1. — Hind femora in male tbickened and arcuate, the tibiae dilated at tip . geminata 



Hind femora in male simple 2 



2. — Scutellum yellow ; legs yellow, except tbe bind tarsi 3 



Scutellum black with a yellow margin ; front of female mucb narrowed above : 



hind femora in part black . parvula, Boscii 



Scutellum black or brown with a yellow border; front of female above only a 



little narrowed; hind femora wholly yellow marginata, var. 



3. — Front of female only a little narrowed above; third-fifth abdominal segments 



with narrow lateral yellow margins marginata 



Front of female much narrowed above; third-fifth abdominal segments not yel- 

 low on the margins polita 



For other species, see descriptions, and also appendix. 



Mesograpta polita. 



Scava poliia Say, J. Acad. Phil., iii, G8; Compl. Wr,, ii, 77. 



Syrphu8 poliUts Say, Amer. Entom., i, pi. xi, fig. 8 ; Wiedemann, Auss. Zw. 



Ins., ii, V.i2, 28. 

 Syrphus cingnlaUtlus Macciuart, Dipt. Exot., 4e Suppl., 155, 53. (Type compared 



by Oaten Sacken.) 

 Syrphus heclicus Jaennicke, Neue Exot. Dipt., 90. 



Habitat. — North Carolina, Kansas, Connecticut, Georgia!, Cuba, 



(O.S.). 



