INTRODUCTION. XXIX 



This attempt at subdivision, based upon the antenna and 

 palpi, was all that liad been made until a comparatively recent 

 date. It is the classification followed by Loew in the first 

 volume of the Monographs published as late as 1860. In 

 1863 Brauer proposed a more rational division of the diptera 

 into tlie two suborders, Orthorrhaplia and Cyclorrhapha, based 

 chiefly upon larval and ])upal characters. Their characters 

 in a later publication he gives as follows : 



Larvse with a "jaw-capsule" (Kieforkapsel) or a differentiated head. 

 Pup* free or enclosed in the larval skin ; in either case the larval skin 

 hursts for the extrication of the pupa or imago in a T-shaped opening on 

 the back of the anterior end, or rarely in a transverse rent between the 

 eighth and ninth abdominal rings. The imago lacks the frontal lunule 

 and ptilinum Okthorkiiapiia. 



Larvae without differentiated head. Pup;e always e?ielosed in the hard- 

 ened larval skin (forming the so-called puparium); the imago always 

 escaping from the anterior end through a circular orifice. Frontal lunule 

 present; ptilinum usually present Cyclorkhapha. 



More recently Brauer has proposed a further subdivision of 

 the suborders into tribes and groups as follows : 



SUBOKDKK ORTIIOKKHAPHA. 



Section I. Nematocera. 



Tribe 1. Eucephala. Families Mycetophilidae, Bibionida;, Chiro- 

 nomidae, Culicida?, Blepharocerid;e, Sinmliidaj, Psychodida;, Pty- 

 chopteridaj, Rl ^hidtc ^ ^ 

 Tribe 2. Oligoneura. Family Cecidomyida;. 

 Tribe 3. Polyneura. Tii)ulida!, Limnobiidie. 

 Section II. Brachycera. 



Tribe 4. Acroptera. Family Lonchoj)terida\ 

 Tribe o. Platygenya. 



Group 1. Homodactyla. 



Suj)erfamily 1. Notacantlia. Families Stratomyida?, Xylo- 



phagida'. 

 Superfamily 2. Tanystoma. Families Tabanida', Acan- 



thromeridaj, Lei)tida!. 

 Superfamily -i. Bombylimorpha. Families Nemistriiiidaj, 

 Acroceridse. 



