13 



Haltcre : — Entirely yellow. 



One female. 



Typc ¡ocaStij: — Quebrada de Liües, Tucuman (2 Febriiary, R. C= 

 Shannon). 



This species is named in honor of Enrique Lyneh Arribalzaga 

 who with his brother, have been the foremost workers on the Díptera 

 cf Argentina. 



Subfamily Acalpterae 

 Family Tanypezidae 



The flies of tliis fami\v are nsiially found in shady woods, resting 

 on the broad leaves of p'ants. The larvae, very probably, are phyto- 

 phagoiis. 



Tanypezidae : ■ — Rather small to modérate sized flies. Byes very 

 large, ccenpying mnch the greater portion of the head siirfaee; arista 

 piibescent; no oral vibrissae ; legs long- and slender, the tarsi longer 

 than the tibiae; aiixiliary vein distinet ; first lonoitiidinal vein ten.i- 

 inating near the middle of the costa; apex of fourth vein distinctly 

 approximating that of the third; bristles of head and thorax well de- 

 veloped. 



Tanypeza dallasi, new species. 



Male: — Modérate size (12 mm. ; wings 9.5 mm.) ; black with 

 silvery prninose markings. 



líead: — Much shorter than high; in frontal aspect subellipitical ; 

 front long and narrow (1 by 6, narrowest width) velvety black with 

 a large silvery prninose spot above ocelli and silvery prninose on lower 

 sides ; ocelli well removed frora the posterior orbit. Bristles : — A 

 small pair of post ocellars: a large pair of inner verticals and two 

 pairs of modérate fronto-orbitals. Antenna yellow; length of third 

 joint twice its greatest width; arista black, much longer than length 

 of antenna, short pubescent. Face of modérate width, the lateral 

 niargins diverging downwardly; silvery pruinosity of the sides cont- 

 inuous with that on the lower portions of the front; the median 

 portion of face blackish above, yellowish bclow; palpi black, proboscis 

 yellow. 



Thorax: — Mesonotum black. overlaid with yellowish pruinosity 

 >\hich is more pronounced posteriorly and rather bright silvery on and 

 above the notopleura ; pleurae black with a silvery prninose área cover- 

 ing the upper portion of the sternopleura, the posterior two-thirds of 

 the mesoplenra and wliicli is continuous with tlie silvery área of the 

 notopleura ; silvery área on the hypopleura and another on the meta- 

 pleura extending backwards and across the metanotum. Bristles (for 

 cach lateral half of thorax) ; one humeral, one sublateral, two noto- 

 pleurals, three posterior dorsocentrals, one supra-alar, two on the 

 post alar callus; the pleurae without bristles except for two strong 

 and several weak ones on the upper posterior córner of the meso- 



