18 



0. Chrysogaster (? Orthoneura) laevigata, sp. n. 



$ . Length 4'5 to 5 mm. 



A glittering metallic species, which recalls our European Lio- 

 gaster metallina, but has a very elongate linear third antennal 

 joint, a velvety black transverse band on the second abdominal 

 segment, and a dark cross-band on the wings before the tip. 



Head smaller than in the preceding species, with the frons 

 shorter, the antennae being inserted above the middle of the eyes 

 (not below as in C. spiloptera] ; entirely shining, metallic bluish, 

 aeneous on the lunula ; frons with an arcuate prominence above 

 the antennae and with two median longitudinal elevated lines, but 

 without any trace of transverse furrows ; it bears dark and sparse, 

 but rather long, hairs ; face rounded, less produced below, with 

 sparse hairs; eyes bare, adorned with two perpendicular dark bands, 

 the space between which is equal to that on each side of them ; 

 antennae black, dark yellowish toAvards the base, widely separated ; 

 third joint narrow, linear, three times as long as the first two 

 together ; arista bare. Thorax aeneous on the sides and on the 

 pleurae, purplish blue on the disc behind the suture ; dorsum clothed 

 with short pale hair. Scutellum aeneous, smaller than in the 

 preceding species, margined, clothed with rather long hair, chiefly 

 toAvards hind border. iSquamulae white, the thoracic pair Avith a 

 long fringe ; plumulo) and halteres pale yellowish. Abdomen 

 entirely shining, with short pubescence ; aeneous at the base and 

 sides and on the fourth segment, and violaceous in the middle of 

 the disc ; the second segment bears besides a velvety black band 

 on the hind border, AA r hich does not reach the sides and is rounded 

 anteriorly, attaining the middle of the segment. Venter shining 

 aeneous, with coppery reflexions. Legs short and stout, with short 

 pale pubescence ; femora black, tibiae and tarsi reddish yellow. 

 Wings hyaline, Avith yellowish base and stigma ; veins darkened 

 towards the end ; the subapical cross-band is pale broAvn, and runs 

 perpendicularly from the subapical cross-vein to the end of the 

 second longitudinal A r ein ; the posterior cross-vein is also narrowly 

 margined Avith fuscous ; subapical cross-vein but slightly recurrent, 

 almost perpendicular. 



Type $ , and another specimen from Obuasi, Ashanti, 1. ix. 1907, 

 "caught hovering in sAvamp" (Dr. W. M. Graham). 



Genus 3. MELANOSTOMA, Schiner (1860). 



A iiumluT of ill-defined African forms of this genus have 

 been described, tho synonvmv of which is given in the List 

 (p. 3). 



With the material available 1 haA r e distinguished the following 

 forms, which perhaps can be reduced to fiA r e good species ; JU. uiel- 

 /i mi HI, which 1 recorded in 1908 from Erythraea, is doubtful, as 

 this species does not seem to be represented in the Ethiopian 

 Kt'gion : 



