124 Mr. F. Walker's Characters of undescribed Diptera 



vitta dorsali nigricante, femoribus ciliatis, libiis ciliatis, alis 

 purpureo-nigricantibus, striga discali lurida, apicibus sub- 

 cinereis, halteribus fulvis apice albis. 



Female. — Black, stout, short ; head white on each side above 

 and along the eyes ; two small shining calli ; antennae with a 

 curved horn, which is nearly as long as the third and following 

 joints together ; thorax with a white dot on each side by the base 

 of the wing ; abdomen red, with two yellow basal bands, which 

 beneath are united but widely interrupted in the middle, a blackish 

 stripe in the middle above ; tibiae ciliated ; femora slightly ciliated ; 

 wings blackish, with purple reflections ; a lurid streak in each 

 disk ; tips hyaline, slightly greyish ; halteres tawny, with white tips. 



Length of the body 6 lines; of the wings 12 lines. 



Allied to T. festivus, Wied. 



Amazon Region. 



Tabanus humillimus. 



Fcem. — Nigricans, capita cervino subtus cano, callis duobus 

 (postico minimo) fuscis, antennis fulvis parvis simplicibus, 

 callis humeralibus pedibusque fulvis, pectore cano, abdominis 

 segmentis fulvo-marginatis, alis subcinereis, halteribus testa- 

 ceis. 



Female. — Blackish ; head hoary beneath, fawn colour between 

 the eyes, with a very small brown callus on the vertex and another 

 in front ; eyes dark red, all the facets very small ; mouth and an- 

 tennae tawny, the latter short, slender, simple ; humeral calli and 

 legs tawny ; pectus hoary ; hind borders of the abdominal seg- 

 ments dull tawny ; wings greyish ; veins black, ferruginous to- 

 wards the base ; fore branch of the cubital vein simple, nearly 

 straight ; subanal vein joining the anal at some little distance 

 from the border ; halteres testaceous. 



Length of the body 4 lines ; of the wings 8 lines. 



Celebes. 



Genus Silvius, 

 Silvius nitescens. 



Mas. — Cinereus, subtus testaceus, antennis fulvis, thorace vittis 

 tribus canis, margine tcstaceo, abdomine fulvo, maculis tri- 

 gonis flavo-tomentosis, lituris lateralibus nigricantibus,pedibus 

 fulvis, tarsis piceis, alis subcinereis, halteribus fulvis apice 

 albidis. 



