24 



H. C. EFFLATOUN. 



Ditt. Eritrei., II. 21.75. (1908) et Syrph. aethiop. Mus. Nat. hun- 

 garici, 132. (2).5. {tibialis var.) (1921). 



dimidiatus Lw., Berl. Entom. Zeitsclir., VIL 308.08. (1863) ; 

 WiLLiST., Bull. Unit. Stat. Nat. Mus., (31), 20. (1886) et Biolog. 

 Centr. Amer., Dipt., III. 5.1. (1891); Towns., Psyché, VIII, (259), 

 140. 2. et (260)., 147.2, (1897); Aldr., Catal. N.A. Dipt., 351. (1905). 



tacchetii Rond., Atti. 8oc. Ital. Sci. Nat. Milano, VIII, 

 140. (1865). 



vari'pes Bic, Annal. Soe. Entom. Fr., (5). X. 150.- {Orthonevra) 

 (1880) et (6). V. 249 (Orfhonevra) (1885). 



auricaudatus Bio., Annal. Soc. Entom. Fr., (6). III. 1883. 

 540. 2. (1884); Willist., liull. l^nit. Stat. Nat. Mus., (31), 301. 

 (1886). 



I)/Af;XOSIS:^l-iicc Avith a hlaek iiiiddlc liii;> in hotli sexes ; 

 scutelhun entirely black in hoth sexes. 



DKSCRIPTIOS :—-Male : Face from light to dark shining 

 yellow with a black niiddle line which extends from between the 

 antennai to the upper mouth-edge; this line is ratlier widened about 

 its lower part and is Droduced quite one third of the width of the 

 eye. Pubêsoence delicâta white and equal everywhere exeept on the 

 middle line. Jowls small with white pubescence which is continued 

 on to the occiput. Vertex shining black, elongate and very pointed 

 in front and possesses inconspicucais blackish pubescenoe. Eyes 

 touching for a short distance and with short inconspicuous 

 whitish" pubescence which has no tendency to run into stripes. 

 Antennaî'with the two basai joints black ; the rather long 

 third joint which is usually about thrce times as long as broad 

 is generally black above and yellow below; aiista brown, bare and 

 not quite as long as the third antennal joint. 



Thorax aeneous-black, shining, and rather coarsely punctate; 

 it is clothed with fairly abundant and erect whitish pubescence, 

 which is whiter and mueh longer on the plcurac. Scntcllum with a 

 similai' iiubescence as that of tlie thorax and williout any trace of 

 light colour. 



Abdomen shining black, with a punctuation which is coarser 

 on the basai half, but the extrême hind margins of the segments 

 are impunctate and very shining; sometimes it bears orange-red or 

 yellow markings, which colour may extend on to ail the segments, 

 exeept the basai one, such as in the varieties mentioned below. 

 The second segment is longer than the basai, the third longer thaii 

 the second, the fonrth longer than the third, and the fifth is much 

 shorter than anv of the four others but is verv obvions ; the abdo- 



