126 MB. walker's catalo&ue of dipterous insects 



Megistogaster, Macq. Mem. Soc. Sci. Nat. de Lille, 1850, 185. 



Body narrow, cylindrical, slightly setose. Face sHghtly retracted and ob- 

 lique ; epistoma not prominent ; facialia without bristles. AntennsE very 

 long ; 3rd joint nearly luiear, six times the length of the 2nd ; arista bare, 

 slender, a httle longer than the 3rd joint. Legs setose, rather long. Wings 

 narrow ; prsebrachial vein forming an obtuse angle at its flexiu-e, nearly 

 straight fi-om thence to its tip, joining the costal at somewhat in front of 

 the tip of the whig ; discal transverse vein undulating, parted by about 

 half its length from the border and from the flexm-e of the prsebrachial. 

 Type. Tachina Diabolus, Wied. 



113. Megistogaster Imbrasus, Walk. Capt. Dipt. pt. 4. 781. ( Tacluna.) 

 Inhabits also China, 



The female has silvery-wliite tomentum in front of the head. 



Subfam. Dexides, Walk. 



G-en. Dexia, Meigen. 



114. Dexia MnsroA, n. s., mas. Viridis, capite cano, frontalibus atris, oculis 

 nudis, antennis pedibusque nigi-is, abdomine nigro albo-tomentoso fasciis 

 duabus latissimis interruptis apiceque testaceis, alls fuscis, halteribus 

 testaceis. 



Male. Green, shining. Head with hoary tomentum in front and beneath, 

 and with gUded tomentum along the eyes above; frontaUa deep black, 

 widenmg ua front ; faciaha without bristles ; epistoma not prominent. 

 Eyes bare. Proboscis and palpi testaceous. Antennse black; 3rd joint 

 elongate ; arista pubescent. Pectus and sides of the thorax with wliitish 

 tomentum. Abdomen black, shining, oblanceolate, about twice the length 

 of the thorax, armed ^vith several very stout spines ; segments with whitish 

 reflections, and with two very broad interrupted testaceous bands; tip 

 testaceous. Legs black. Wmgs brown ; veins black ; prsebrachial vein 

 emitting a branch at its flexm'e wliich forms an almost right angle, from 

 whence it is indistinctly undulating to its tip, which joins the costal at 

 somewhat m fi'ont of the tip of the wing ; discal transverse vein undu- 

 lating, parted by less than half its length from the border, and by more 

 than half its length from the flexure of the prsebrachial. Alulse sUghtly 

 greyish. Halteres testaceous. Length of the body 6 lines ; of the wmgs 

 8 lines. 



115. Dexia extendens, n. s. (gen. Thelaii-a, Desv.), foem. Atra, capite 

 cano-tomentoso, vertice cervino, palpis antennisque ferrugineis, thorace 

 vittis tribus fasciaque testaceo-tomentosis, seuteUi apice testaceo, abdomine 

 fasciis duabus latis albido-tomentosis, pedibus piceis, femoribus fulvis, ahs 

 nigro-fuscis postice cinereis, halteribus fulvis. 



Female. Deep black. Head with hoary tomentimi ; vertex with fawn- 

 colom-ed tomentum ; frontaha broad ; epistoma, proboscis and palpi fci-ru- 

 ginous. Antennse ferruginous, much shorter than the face ; arista plumose. 

 Thorax with tlu-ee stripes and one liinder band of testaceous tomentum ; 

 scutellum testaceous at the tip. Pectus with whitish tomentiun. Abdomen 

 with some stout bristles, and with two broad bands of whitish tomentum. 



