Qg(j Syrphidae. 



is as long as or a little longer than the antenna itself; the basal 

 antennal joints have the usual small bristles at the apical margin, the 

 third joint and arista microscopically hairy, the latter sometimes visibly 

 pubescent, Epistoma varying in breadth, from rather narrow {cinctus) 

 to broader or very broad (barbifrons) ; it is a little hollowed below 

 the antennæ and has a moderately prominent central knob, generally 

 about as prominent as the antennal prominence; the front mouth 

 edge is considerably retreating. The epistoma is yellow, often with 

 a broader or narrower and more or less complete black middle stripe; 

 in rare cases the stripe may be very broad, or the epistoma may be 

 quite black in the male. The epistoma has short, erect hairs. Jowls 

 broader or narrower, slightly or not descending; they are separated 

 from the epistoma by a more or less complete furrow or groove, 

 reaching upwards at the front eye-margin towards or about to the 

 height of the central knob. Oral cone well developed with the horse- 

 shoe-shaped clypeus lying on the front side. Proboscis of medium 

 length. Labrum {ribesii) strong, somewhat high at the base, semi- 

 tubular, the apical processes of usual shape, about equal in length, 

 the median delicate, cleft to the base, with the apices diverging and 

 each branch with fine emergences at the apex and on the inside ; the 

 upper lateral processes likewise very delicate and sharply pointed, the 

 lower lateral processes broad, with rounded apex ; along the lateral 

 margins of labrum, on the inside is the usual row of small pipillæ or 

 warts; hypopharynx of the length of labrum, somewhat semitubular, 

 a little attenuated towards the end, but the apex rounded; the sali- 

 vary duet distinct; maxillæ with a slightly curved, knife-shaped lacinia, 

 and with a not long, thread-like palpus, a little longer than the lacinia, 

 the palpus bears some long hairs or fine bristles and is beset with 

 fine, short hairs; the lacinia is very densely beset with microscopical 

 hairs or spines, arranged somewhat in longitudinal rows as usual. 

 Labium with a medium long connecting membrane; the basal part of 

 labium well chitinised, triangularly incised at each end, somewhat shorter 

 than the rather large and broad, oval labella. Thorax quadrate or 

 nearly so, the side margins often a little yellowish; very rarely {gut- 

 tatus) it may have pale spots on the disc in front of scutellum. 

 Scutellum yellow or brownish yellow, sometimes only translucently 

 yellowish, and in rare cases almost quite black, only a little brownish 

 on the disc; it has a fringe of hairs below the margin (only in 

 annuUpes indistinct). No bristles on thorax or scutellum. Pleura 

 æneous, metapleura with short, dense hairs. Abdomen of somewhat 

 varying shape ; it may be ovate, and then either more or less arched, 

 or rather flat and with distinctly marked, a little raised side margins ; 



