252 ME. walker's catalogue of dipterous insects 



Female. Testaceous, slender; thorax witli three black lines, of which 

 the middle one is much more slender than the others ; pectus with 

 a black streak on each side ; abdomen lanceolate, cuneiform and 

 shining towards the tip, about twice the length of the thorax ; tip and 

 a spot on each side beyond the middle black ; wings naiTOw, slightly 

 cinereous ; costa black from one-fourth of its length to the end of the 

 prsebrachial vein ; veins black ; discal transverse vein straight, oblique, 

 parted by less than one-fourth of its length from the border, and by 

 full twice its length from the praebrachial transverse. Length of the 

 body 4^ lines ; of the wings 8 lines, 



72. Dacus concisus, n. s. Fcem. Niger, gracilis, capite flavo ma- 

 culis nigris, arista plumosa, thorace vittis quatuor flavis, abdomine fusi- 

 form! petiolato apice attenuato fulvo maculis duabus basalibus flavis, 

 femoribus flavo vittatis, alis Umpidis nigricante bivittatis. 



Female. Black, slender ; head yellow, with four black spots on the hind 

 ])art ; front with a black dot on each side, and with a black spot which 

 is furcate hindward ; face with an interrupted black band ; antennae 

 tawny, not reaching the epistoma ; 3rd joint linear, about one-third 

 of the length of the 2nd; arista plumose; thorax with four yellow 

 stripes, of which the outer pair are curved and extend obliquely along 

 the sides of the pectus ; metatliorax with a yellow stripe ; abdomen 

 fusiform, petiolated at the base, attenuated at the tip, with a yellow 

 spot near the base, and another near the tip which is tawny ; 

 femora with a yellow band near the base, tawny towards the tips ; 

 tarsi yellowish towards the base; wings limpid, with two blackish 

 stripes which are imited towards the base — one costal, the other 

 occupying the middle part of the hind border ; veins black ; prsebra- 

 chial vein very slightly angular ; discal transverse vein oblique, nearly 

 straight, parted by less than one-fourth of its length from the border, 

 and by a little more than its length from the long oblique pra;brachial 

 transverse vein ; halteres yellow. Length of the body 4 lines ; of 

 the wings 8 lines. 



Gen. RioxA, Walk. 



73. RioxA FORMosiPENNis, n. s. Mas. Testacea, capite vitta nigra, 

 arista plumosa, thoracis vittis sex metathorace abdominisque fasciis 

 tribus nigris, femoribus posticis piceis, alis nigricantibus basi costaque 

 luridis, punctis septem discalibus strigisque posticis albis. 



Male. Testaceous, with black bristles ; head with a black stripe above ; 

 antennae not more than half the length of the face ; 3rd joint conical, 

 less than twice the length of the 2nd ; arista long, plumose ; thorax 

 with six black stripes, the middle pair dislocated in the middle ; pectus 

 with two black stripes hindward ; metathorax black, shining; abdo- 

 men with three black bands, the 3rd very broad ; hind femora piceous ; 

 wings blackish, lurid in front and behind at the base, with white 



