II. 



SYSTEMATIC DISTRIBUTION OF THE OBTALIDi!. 



The last, but not the easiest, task which it remains for me to 

 fulfil is the systematic distribution of the family Ortalidse. In 

 attempting it, I will principally confine myself to those genera 

 and species which I possess in my own collection. Only in 

 exceptional instances, and with especial caution, will I allow 

 myself to transgress the limit of what I have, or have had, before 

 me, as the statements concerning the other genera and species 

 which have been published are seldom complete enough to afford 

 the necessary data for the discrimination of their position in the 

 system. 



In order to obtain a preliminary survey I first divide the 

 Ortalidse in two large divisions ; to the first belong those which 

 have the first longitudinal vein beset with bristles or hairs ; to 

 the second, those the first longitudinal vein of which is bare. 



FIRST DIVISION. 



Ortalid^b with a Bristly or Hairy First Longitudinal 



Yein. 



Among the European Ortalidse, of this division five diverging 

 forms will easily be noticed : 1. Adapsilia; 2. Ortalis Meig., 

 of course to the exclusion of 0. syngenesise and vibrans; 3. 

 Platy stoma ; 4. Cephalia; and 5. Scatophaga fasciata Fab. 



All the other European genera with a bristly first longitudinal 

 vein can be grouped around these five types, with the exception 

 perhaps of the somewhat recalcitrant genus Psairoptera. The 

 same may be said of all the exotic Ortalidse of this division 

 which I know of. Thus, the Ortalidse of the first division may 

 be naturally divided into five groups. 



We will characterize these groups only after having made out 

 the genera which belong to them, and we will proceed to the dis- 

 covery of these genera by means of the principal characters which 

 distinguish the above-mentioned five types. 

 ( 32 ) 



