ORTALID.E — AMPHICNEPHES. 83 



costa to the third longitudinal vein and situated before the break 

 in the second vein, a round spot between both crossveins, the 

 alula and two large crescents on the posterior margin hyaline ; 

 the crescents show a pale shade of brownish towards the posterior 

 margin. Halteres altogether pale yellow. 



Hab. Carolina (Zimmerman). 



Observation 1. — The above is a translation of Gerstaecker's 

 description of the specimens in the Berlin Museum. The species 

 is distinguished enough to render the discussion of its specific 

 rights useless. I will only notice here, that when the author 

 says that the fifth abdominal segment in the female gradually 

 passes into the capsule-shaped ovipositor, this expression is not 

 to be understood literally ; in the two species which I have seen, 

 such a transition is not visible. When the author calls the first 

 two antennal joints of P. pterophorina "beset with blackish 

 bristles, as in the preceding species (P. undata and vespertilio)" 

 I would observe that in P. undata this pubescence is in reality 

 yellow, and assumes a ferruginous or even blackish tinge only 

 when seen against the light. 



Observation 2. — A fifth American species is described by 

 Macquart (Dipt. Exot. Suppl. IV, p. 281, Tab. XXYI, f. 1) as 

 Oxycephala fenestrata. His data are not even sufficient to 

 ascertain whether the species really is a Pyrgota. Moreover it 

 is not distinctly stated whether this species belongs to North 

 America. 



Second Section: Platystomina. 



Gen. I. AMPHICNEPHES nov. gen. 



Ckaract. — Front of- medium breadth, not narrower anteriorly. 

 Antenna reaching down to the edge of the mouth. 

 Face excavated, without distinct antennal foveae ; occiput but little 



turgid ; eyes high ; cheeks narrow. 

 Scutellum large, flat, with four bristles. 

 Wings very broad ; the longitudinal veins straight and conspicuously 



diverging ; anal cell shorter than the preceding basal cell ; its 



posterior angle rounded. 



Small, metallic-colored species, the wings of which show a 

 picture not unlike that of the species of Platystoma, and the 

 general habitus of which is less like the species of Rivellia than 



