192 DIPTERA OP NORTH AMERICA. [PART III 



Gen. XI. MULAIVOLOIHA nov. gen. 



Char act. — Front rather broad, somewhat narrower anteriorly, not exca- 

 vated ; the posterior ocelli not far removed from the edge of the 

 vertex ; the anterior one at a considerable distauce from them. 



Antennal arista bare. 



A strong mesothoracic bristle and a very weak prothoracic one. 



Scutellum with four bristles ; metathorax rather perpendicular. 



Femora not incrassate, only the hindmost ones with spines near the 

 tip. 



Wings: posterior angle of the anal cell quite obtuse; the crossveins 

 not approximate; the last section of the fourth longitudinal vein 

 parallel to the third. 



The species of this genus are distinguished by their robust 

 thorax and short oval abdomen ; the surface of the latter is not 

 smooth, but entirely covered by shallow scars, almost chagreened. 

 The picture of the wings of the species known to me consists of 

 a black border of the anterior margin of the wing and of the 

 apex, and of a narrow black streak over the small crossvein. 



The typical species is a Brazilian one, described by Wiede- 

 mann as Trypeta cyanogaster. As, in Wiedemann's description, 

 the plastic characters are not sufficiently taken notice of, I will 

 give the description of a species closely related to his. 



1. Wt. affinis n. sp. % . — (Tab. IX, f. 29.) Rufa, tibiis concoloribus, 

 posticis tamen basim versus infuscatis, abdomine ex violaceo chalybeo; 

 alae hyalina?, costa cum apice et vena transversa media anuuste nigro- 

 limbatis. 



Red, the tibiae of the same color, the hindmost ones infuscated towards 

 the basis ; abdomen violet steel-blue ; wings hyaline, anterior margin 

 and apex, as well as the small crossvein, with a narrow black border. 

 Long. corp. 0.24; long. al. 0.24. 



Ferruginous-red, shining; abdomen of a dark steel-blue color, 

 somewhat verging on violet. Front rather broad, somewhat 

 narrower anteriorly, sometimes tinged with yellow on the sides; 

 the short and thin hairs upon it are inserted in small, very shallow, 

 and hence hardly perceptible pits. The two superior ocelli are 

 quite near the vertex ; the anterior one is quite a distance from 

 them, but still above the middle of the front; bristles of the 

 vertex, the lateral ones and the two bristles near the ocelli, are 

 present. Antenna? reaching a little beyond the border of the 

 mouth; the third joint long, sometimes more reddish-brown. 



