CHARACTERISTICS OF FAMILIES OF DIPTERA. >aii 



Family Tabanidcc. 



Three basal cells, very prolonged. Third longitudinal vein furcate. 

 Two intercalary veins always present; marginal running around 

 whole border. Tegulje large. Head broader than thorax. Third 

 joint of antennae annulate, generally entire ; no terminal bristle. 

 Proboscis strong and prominent. Empodium large, pulvilliform. 



Family Leptidce. 



Head smaller than in Tabanidce. Antennae short, last joint 

 rounded, furnished with terminal bristle. 



Family Asilidce. 



Three basal cells, much prolonged. Third longitudinal vein 

 furcate, and the two intercalary veins present. Head short and 

 broad ; eyes prominent. Third joint of antennae simple. Thorax 

 narrowed in front. Empodium like a horny bristle. 



Family Bomhylida:. 



Three basal cells much prolonged ; the anterior intercalary 

 present, the posterior always wanting. Proboscis prominent, long 

 and slender. Third joint of antennce simple, generally provided with 

 a bristle or tuft at the end. Empodium rudimentary. 



Family Therevidcv. 



Three basal cells prolonged ; both intercalary veins present. 

 Third longitudinal vein furcate. Antennae with short terminal bristle. 

 No empodium. 



P'amily Scenopinido!. 



Three basal cells, very large ; the third closed far from the border 

 of wing. No intercalary vein ; third longitudinal vein furcate. 

 Antennce with third joint very long, no terminal bristle. No em- 

 podium. 



Family Cyrtida;. 



Eyes very large. Tegular vaulted, very large. Basal cells long. 

 Neuration very variable, often incomplete. Terminal antennal joint 

 simple. Tibiae spurless. Empodium large, pulvilliform. 



Family EmpidcB. 



Three basal cells complete, large \ the third shorter than second. 

 Posterior basal transverse vein parallel to border of wing. Anterior 

 intercalary present, posterior wanting. Antennce with first two joints 

 very small, hardly distinct ; third not annulated ; often with a ter- 

 minal bristle. Empodium membranaceous. 



