ORTALID^E SYSTEMATIC DISTRIBUTION. 69 



sequel, can also be placed in the genus Ccelometopia, although 

 the ocelli, which here, as well as in the latter genus, are rather 

 much forward on the front and close to each other, are placed 

 here upon a very gentle elevation, while in Ccelometopia the 

 projection which bears them is quite high. 



Closely related to Ccelometopia is the species described by 

 Wiedemann as Trypeta cyanogaster. It is not a real Ccdome- 

 topia, as its posterior ocelli are less remote from the vertex and 

 the anterior one quite distant from them ; moreover the third 

 and fourth longitudinal veins are parallel here and the hind 

 femora alone bear a few bristles, while in Ccelometopia all the 

 femora are beset with spines. For this reason Trypeta cyano- 

 gaster has to be considered as the type of a new genus, which 

 may be called MELANOLOMA. A second species of this genus, 

 from Brazil, has the same picture of the wings as M. cyanogaster, 

 consisting in a black border of the costal margin and of the small 

 crossvein. 



Other Brazilian Ortalidse resemble the genus Melanoloma in 

 the fact that the third and fourth longitudinal veins are parallel ; 

 the agreement in the structure of the rest of the body, especially 

 of the head, is very striking. These species differ, however, in all 

 the femora being spinous, in the arista being distinctly pubescent, 

 in the still greater distance between the anterior ocellus and the 

 two posterior ones, in the close proximity of the two crossveins 

 of the wings, and in the picture of the wings, which does not 

 consist in a black border on the costa, but in large, crossband- 

 like spots. I deem it useful to introduce for such species a new 

 genus, which I will call HEMIXANTHA ; a species of this genus, 

 jH". spinipes, will be described below. 



That Dacus Jlamcornis Wied., from Brazil, belongs in the 

 same circle of relationship is proved by the original specimen, 

 preserved in the Berlin Museum. 



Before having subjected that specimen to a second and more 

 close examination, I would not venture to decide whether it can 

 be placed in any of the genera, which I have just discussed. As 

 far as I remember, its scutellum bears only two bristles ; this 

 would prevent its identification with any one of those genera, as 

 it is very unlike just those among them which share that character 

 with it. Otherwise it has the same Z>acMS-like structure of the 

 face as most Richardina; the third antennal joint is elongated ; 



