MR. WALKER ON DIPTERA COLLECTED AT MAKESSAR. 133 



123. Idia prolata, n. s. (Group Rhyncomya, Desvoidy). Faun. Vi- 

 ridis, sat angusta, capite testaceo frontalibus facie maculisque duabus 

 anticis nigris, antennis halteribusque testaceis, abdomine cyaneo pur- 

 pureo cupreoque vario fasciis duabus aureo-viridibus, pedibus nigris, 

 alis cinereis basi et apices versus fuscis. 



Female. Green, rather narrow, with slight cinereous tomentura ; head 

 testaceous, white behind ; frontaha and face black and shining, the 

 former linear ; a black spot on each side of the peristoma ; epi- 

 stoma rather prominent ; eyes bare ; antennae testaceous, not near 

 reaching the epistoma, 3rd joint about thrice the length of the 2nd ; 

 abdomen blue, tinged with purple and with cupreous, a little broader 

 than the thorax, with two golden green bands which are widely inter- 

 rupted above ; legs black ; wings grey, brown at the base and towards 

 the tips, with the exception of the hind border; veins black ; prsebra- 

 chial vein forming a much rounded and very obtuse angle at its flex- 

 ure, which is near the border, nearly straight from thence to its tip ; 

 discal transverse vein slightly curved outward, parted by much less 

 than its length from the border, and by about its length from the 

 flexure of the prsebrachial ; alulae and halteres testaceous. Length of 

 the body 3| lines ; of the wings 5 lines. 



G-en. Mtisca, Idnn. 



124. MuscA PROSPERA, u. s. (Gcu. Silbomyia, Macq.). Foem. Aurato- 

 viridis, capite argenteo, facie palpis antennis pedibusque nigris, oculis 

 nudis, pectore raaculis duabus argenteis, abdomine spinoso, apice pur- 

 pureo maculis duabus argenteis, alis nigricantibus basi et apud costam 

 nigris, alulis albis. Var. /3. Thoracis disco cupreo, abdomine subtus 

 cyaneo-purpureo. Var. y. Abdominis disco cupreo, palpis fulvis. 



Female. Deep golden green, thickly beset with very stout bristles ; 

 head silvery white ; vertex green on each side ; frontalia piceous, very 

 broad, with long stout bristles on each side ; facialia without bristles ; 

 face black, deeply keeled, the keel partly white ; epistoma slightly 

 prominent ; eyes bare ; palpi long, subclavate ; antennae almost reach- 

 ing the epistoma, 3rd joint full four times the length of the 2nd ; 

 pectus with a silvery spot on each side ; abdomen elongate-oval, a 

 little longer than the thorax, with long stout spines hindward, pur- 

 ple at the tip, where there is a silvery spot on each side ; legs black, 

 very stout ; wings blackish, black at the base and along part of the 

 costa ; veins black ; praebrachial vein forming a rounded right angle 

 at its flexure, near which it is curved inward, and is thence straight to 

 its tip ; discal transverse vein undulating, parted by more than half 

 its length from the border and by less than half its length from the 

 flexure of the praebrachial ; alulae white. Var. ^. Disk of the thorax 

 bright cupreous ; abdomen blue and purple beneath. Var. y. Like 

 i^ar. /3 ; palpi tawny ; disk of the abdomen bright cupreous. Length 

 of the body 7-8 lines ; of the wings 12-14 hues. 



