206 Orthorrhapha brachycera. 



II. Diaphorinae. 



10. Chrysotus Meig. 



Species of small or very small size, of not slender shape and of 

 bright metallic colour. Head a little broader than thorax, short, 

 semiglobular, about as high as broad. Occiput only very slightly 

 arched. Vertex slightly excavated ; frons somewhat decreasing in 

 breadth towards the antennæ; there are as usual a pair of strong 

 ocellar and outer vertical bristles, and a pair of small postvertical 

 bristles, besides there are a pair of small, but distinct bristles behind 

 the ocellar tubercle (perhaps representing the inner vertical bristles). 

 Eyes large, oval, narrowed downwaids; in the living specimens they 

 are metallic green, with reddish reflexes; they are densely short-haired. 

 The eyes are in the male generally very approaching downwards, 

 below the antennæ, or quite touching; the epistoma is thus small, 

 very narrow or quite disappearing downwards; in the females the 

 eyes are more broadly separated, and the epistoina has parallel horders. 

 Only rarely {laesus of Danish species) the eyes are more broadly 

 separated in the male, but the epistoma is however narrowed down- 

 wards, and narrower than in the female. The eye-facets are in the 

 male distinctly enlarged downwards towards the epistoma, but there 

 is no sharp dividing line; in laesus the facets are not or almost not 

 enlarged. The postocular bristles form a single row along the eye- 

 margin, but besides there is a row more inwards on the lower half 

 of occiput, interrupted just above the mouth aperture. Antennæ in- 

 serted near to each other a little above the middle; they are short, 

 five-jointed ; the first joint sometimes somewhat thin, obconical, the 

 second short, likewise obconical, more or less rounded anteriorly, 

 sometimes somewhat triangularly, but slightly or not overlapping the 

 third; this latter is generally small, sometimes larger, and it may be 

 short, higher than long, not pointed, or more equilateral, or fmally a 

 little longer than high and somewhat pointed; it is somewhat roundly 

 incised posteriorly and thus often more or less reniform ; the two last 

 joints form an arista, the first joint of which is quite short; the arista 

 is inserted in a little excision, which is placed on the outside, so that 

 it is not seen, when the antenna is viewed from the inside; the in- 

 sertion is distinctly dorsal or more subapical. The first joint of the 

 antennæ is not haired above, the second has a circlet of bristles at 

 the apex, especially one long above; the third joint has rather strong 

 hairs, and the arista is distinctly, though not densely haired. The 

 epistoma is, as mentioned, generally very narrow in the male, broader 

 in the female; in the male it has a median furrow above; the clypeus is 



