DIPTERA. 355 



Merodon, Meig., Fab. — Milesia, Eristalis, La/. — Sykphvs, Fab., 



Where the abdomen is triangular or conical, without being narrowed 

 at base, and where the external cell of the posterior edge of the 

 wings is deeply emarginated exteriorly. 



M. narcissi; Eristalis narcissi. Fab.; Reaum., Insect. IV, 

 XXX. Obscure-bronze, but covered with fulvous down; legs 

 black ; inner side of the posterior legs tuberculous. 



The larva feeds on the interior of the bulb of the Narcissus *. 



AsciA, Meg., Meig., 

 Where the abdomen is narrowed at base and clavate. The two first 

 closed cells of the posterior edge of the wings terminate in an angle ; 

 the exterior side of the first is straight f. 



Sometimes the palette of the antennae is short, or moderately elon- 

 gated, and either almost orbicular or nearly ovoid. 



Here, as in the last subgenus, the abdomen is narrowed at base and 

 clavate. 



Sphegina, Meig., 

 Where the palette of the antennae is orbicular. The posterior thighs 

 are clavate and spinous underneath \. 



There, the abdomen is either triangular or conical, or almost cy- 

 lindrical. 



In some, the wings hardly extend beyond the abdomen, which is 

 frequently narrow and elongated. 



We will separate those whose posterior thighs are strongly in- 

 flated, with the inner side armed with small spines. The closed cells 

 of the posterior border of the wings are sinuous posteriorly. 



EuMERUs, Meig., 

 To which we unite his ZylotcB, where the abdomen is merely nar- 

 rower and almost linear, and which we formerly placed among the 

 Milesiae. Such is the 



E.pipiens; Musca pipiens, L.; Panz.; Faun. Insect. Germ. 



XXXII, 20. About four lines in length; black; each side of 



the abdomen spotted with white. The humming it produces 



while on the wing is mingled with a sharp sound resembling 



the note of a young chicken §. 



In the two following subgenera, the posterior thighs sometimes 



differ but little from those of the preceding ones, and are sometimes 



thicker, but unidentated at most. 



MiLEsiA, Lat., Fab., Meig. — Trepidia, Meig., 

 Where the two posterior legs are abruptly larger than the others, 

 with thick and unidentated thighs in several. The body is elon- 



* See Meigen. 



t Idem. 



X Idem. 



§ See Meigen, genera Eumerus and Xylota, 



