14 DIPTERA OP NORTH AMERICA. [PART III. 



figure (in the Dipteres Exotiques, II., 3, Tab. xxviii., fig. 8), we 

 would not place it among the Ortalidse, as it shows distinctly 

 spurred front and hind tibia ; these spurs, however, as well as 

 many other things in Macquart's figures, are probably produc- 

 tions of the draughtsman's fancy. In the most slovenly figure 

 of the same species in Macquart's Suites a Buffon, no such 

 spurs are to be found. 



That Dacus podagricus Fab., placed by Wiedemann in Cor- 

 dylura, does not belong to that genus, nor to the Cordyluridse 

 in general, has been recognized long ago. For this species, as 

 well as for similar ones, the genus Richardia has been estab- 

 lished .by Rob. Desvoidy in the family of the Ortalidse. 



The systematic location of Dictya externa Fab. cannot well 

 be ascertained, owing to the insufficient statements of Fabricius 

 as well as of Wiedemann ; the latter are in an insoluble contra- 

 diction to Wiedemann's figure in what regards the shape of 

 the head and the picture on the thorax ; judging by the figure, 

 it would seem that the fly does not belong to the Diplera acalyp- 

 tera at all. 



The genus Rhopalomera, Wied. seems to have been by all later 

 authors unhesitatingly referred to the Ortalidse. I look upon 

 this decision as far from unobjectionable, but can very well con- 

 ceive that a certain resemblance in the shape of the head be- 

 tween the species of Rhopalomera and Plaiystoma (with the 

 genera allied to it), may easily have given rise to such an 

 opinion. The species of Rhopalomera differ in a striking man- 

 ner from all the Ortalidse in the structure of the hypopygium of 

 the male, while in this respect they show a most decided leaning 

 towards the Sapromyzidse, Sciomyzidse, and the families imme- 

 diately connected with them. The females are not provided with 

 a borer-like ovipositor, composed of elongated, retractile joints ; 

 the metanotum is but very little developed, less than usual 

 among the Ortalidse; the front and middle tibiae have, on the 

 upper side, before their end, an erect bristle ; upon the upper side 

 of the hind tibiae, this bristle, in most species, is not distinctly 

 visible among the general pilosity of the tibia ; nevertheless, it 

 is easily recognizable in some species, for instance Rhopalomera 

 pleuropunctata Wied. Such are the characters which, in my 

 opinion, not only render the location of Rhopalomera among 

 the Ortalidae doubtful, but even impossible. If, among the 



