ETHIOPIAN FRUIT-FLIES OF THE GENUS DACUS. 



91 



2. Tridacus sphaeristicus, Speiser, 1910, (fig. 4). 



A male specimen of this fine species from British East Africa, Nairobi, 30.1.1914 

 (Capt. A. 0. Luckman) ; this specimen was named lounsburyi, but is easily distinguished 

 from that species by the characters given in the table. The species seems to be 

 confined to East Africa, having been originally described from Kihmanjoro. 



The previously unknown male is very like the female ; the third abdominal segment 

 is ciliated. The wing pattern is very like that of the preceding species, bub is different 

 in having the large rounded dark spot of a more intensive tinge, filling up the upper 

 corner of the discal cell ; in lounsburyi there is also a hyahne streak along the middle 

 of the first posterior cell (see fig. 10 in Froggatt, 1909), which in sphaeristicus is fairly 

 distinct. 



Fig. 4. Dacus sphaeristicus, Speiser. 



A peculiar character of the species of the present group is to be found in the golden 

 pubescence, which is very dense on the abdomen ; the antennae are very long ; the 

 facial black spots are of triangular (not rounded) shape, with the vertex pointing 

 inwards towards the mouth-edge. It seems from description that D.fuscovittatuSf 

 Graham, from Lagos, also belongs to this same group. 



3. Tridacus armatus, Fabricius, 1805, (fig. 5). 



A single female specimen from S. Nigeria, 3.iv. 1914 {Dr. W. A. Lamborn) of what is 

 undoubtedly the present species, recognisably described by Fabricius and Wiedemann. 

 In Prof. Silvestri's paper I have misinterpreted it, as stated below. 



The black facial spots are prolonged below into a point towards the mouth-edge ; 

 the frontal orbits are yellowish, with three dark spots on each side ; the postsutural 

 yellow stripes on the thorax are rather broad ; humeral calli entirely yellow ; meso- 

 pleural stripe broad, but not extended above along the suture ; there is a yellow streak 

 before the suture, in contact with the lateral curved stripes ; hypopleural spots as in 

 vertebratus. Ovipositor very long and pointed, and from this character is very 

 probably derived the specific name. Hind femora entirely yellow ; hind praetarsi 

 ciliated below. AVings with very dark fore-band, filling two-thirds of the breadth 

 of the first posterior cell ; anal band very broad ; last portion of fomth vein gently 

 bisinuous. 



