ORTALIDiE. — INTRODUCTION. 31 



ovipositor, similar to that of the Ortalidae, sufficiently distinguish 

 the Sapromyzidae and Sciomyzidae. 



Diagnostic or Artificial Definition of the Ortalidae. 



The statements about the relationship of the Ortalidae prove 

 that the following characters are sufficient to distinguish this 

 family from all the others, in other words, to constitute its arti- 

 ficial definition. 



Male with a rolled-up, long penis ; female with a three-jointed, 

 horny ovipositor, ending in a simple point. Front without a 

 second lateral row of bristles. No vibrissa?. Complete venation 

 of the Diptera acalyptera ; auxiliary vein distinct to its very tip, 

 ending in the costa at an acute angle; the two posterior basal 

 cells large. The middle tibiae alone are provided with spurs ; all 

 the tibiae are without an erect bristle before the end of their 

 upper side. 



