Sept., 19 14.] Alexander: Tanypremna and Megistocera. 207 



Characters of the Genus. 



Frontal prolongation of the head very short and stout, about as 

 deep as long; the nasus long and prominent, clothed at the tip with 

 long hairs; palpi with the last segment longer than any of the others. 

 Antennae very short, the basal segments larger, the flagellar segments 

 oval, more elongated toward the end. Front very broad between the 

 eyes with no protuberence. 



Prothorax viewed from the side very narrow, the scutellum closely 

 applied to the mesonotal prjescutum and the head, in turn, closely 

 applied to this. Mesonotal pn-escutum very gibbous, partly or almost 

 entirely concealing the head when viewed from above. Halteres long 

 and slender. Legs very long and slender, the tarsi especially being 

 excessively elongated. 



Wings with vein Sc long, Sc^ persistent at the wing-margin and 

 quite close to R^ at its tip; Rs short, usually arcuated but sometimes 

 straight though never so square at the origin as in Brachypremna; 

 R^ usually distinct, oblique, rarely vertical as in Brachypremna. 

 Second anal vein usually long and not ending close in the anal angle 

 of the wings. In longipcs Fabricius, R., is swung proximad at its tip 

 so that it is very close to R^ at the wing-margin; Rs is oblique, 

 straight and second anal is rather short. T. cohnnbiana has a strong 

 supernumerary cross-vein in cell M, and T. regina has this cross- 

 vein and spurs of many other in the basal cells . 



Abdomen elongated, in the females of some species, excessively 

 long and slender. 



Coloration. — Usually light yellow, the thoracic dorsum dark brown, 

 the pleurae yellow with brown transverse bands. Legs brown, the 

 segments having more or less white. Wings usually subhyaline with 

 the veins indistinctly seamed with darker, rarely the whole disk 

 marbled with darker. 



A Key to the American Species of T.\nypremna Ostexx Sacken. 



1. Tibiffi with more or less white before or at its tip 2 



Tibiae with the base abruptly white but the remainder of the segment dark 



colored 4 



2. First tarsal segment broadly white medially, dark at both ends ; remaining 



tarsal segments entirely white ; [radial sector of the wings short, straight, 

 oblique, forming a V with the deflection of i^o+sl- (Guiana, Brazil.) 



longipes Fabricius. 

 Tarsal segments one and two tipped with white 3 



