ORTALIDJE SYSTEMATIC DISTRIBUTION. 51 



Body rather robust, the bristles upon the vertex, upon the 

 posterior part of the thorax and upon the scutellum long. 



Antennae of medium length ; the anterior corner of the third 

 joint acute; arista feathery. Face excavated above, and with a 

 projecting bump below. 



Oral opening broader than long ; proboscis very stout. 



Wings rather broad; longitudinal veins diverging; the. first, 

 third, and fifth beset with bristles; posterior angle of the anal 

 cell not acute ; the picture of the wings is not unlike that pre- 

 vailing in the genus Aciura. 



Rather closely related to Piara is the genus TRAPHERA, which 

 I propose to establish with OrtaUs chalybea Wied. for its type. 

 It also stands very near the Platystomina and may easily be con- 

 sidered as one of them, as the mesothoracic bristle is but very 

 little conspicuous and the fifth segment of the female abdomen is 

 also very much abbreviated. The principal differences between 

 Traphera and Piara lie in the structure of the head and of the 

 wings. The head of Traphera is not unlike that of Platystoma, 

 but the lower part of the occiput is but very little turgid; the 

 vertical diameter of the eyes is very long, the horizontal, on the 

 contrary, very short; the first two anteunal joints are short ; the 

 third pointed oval ; the arista feathery ; the face is descending 

 obliquely, excavated under the antennae, convex below; the 

 clypeus is very much developed, its vertical diameter rather large, 

 the horizontal one small; proboscis very much incrassated. 

 Thorax stout and convex; its dorsum is provided with bristles 

 only on the sides and posteriorly. Scutellum generally with 

 eight bristles. Wings comparatively short and broad, with 

 bristly hairs on their anterior margin; the whole of the first 

 longitudinal vein is strongly bristly and shows, in the vicinity of 

 the somewhat obliterate end of the auxiliary vein, a peculiar 

 break; the basal half of the third longitudinal vein is beset with 

 bristles; the posterior crossvein is oblique, so that the posterior 

 angle of the discal cell is very acute ; the anal cell is rounded at 

 the end and its posterior angle withdrawn in a peculiar manner. 

 The wings are of a dark color, marked with pale bands starting 

 from the posterior margin and abbreviated in front. 



While both of these genera are very near the Platystomina, the 

 two which we have yet to mention approach the Ortalina. They 

 are: DIACRITA, introduced by Gerstaecker, and a genus to be 



