DIPTERA 207 



The two sub-orders of Nemocera and Athericera are readily 

 distinguished and remembered. The next thing to note is 

 that there are very many connecting forms, which are not 

 wholly Nemoceran, nor wholly Athericeran. Thus the antenna 

 may have more than three joints, though they are not so 

 numerous, nor so similar tQ one another as in Nemocera ; the 

 third joint may be more or less divided into segments, and 

 the bristle, if present, may be terminal, instead of springing 

 from the base of the third joint ; lastly, the larval skin may be 

 retained only for a short time. Various combinations of such 

 characters are also met with. Thus Cecidomyia (Hessian-fly, 

 etc.), a Nemoceran, retains the larval skin like an Athericeran, 

 but has a true Nemoceran antenna. We shall here recognise 

 the existence of a transitional group, Brachycera, the members 

 of which are to be recognised only by the negative character 

 that they are not truly either Nemoceran or Athericeran. 



Sub-order I. — Nemocera 



Antenna beaded, of six or more joints, the second of which 

 is often enlarged. The palps are 4-s-jointed, and often 

 conspicuous. The larval skin is cast at pupation, the pupa 

 consisting of the body of the fly enclosed in a temporary skin. 



The gall -midges {Ceddomytdce) are a very numerous 



Brauer's nomenclature, except that his Orthorrhapha Brachycera I consider 

 as a separate sub - Order, while he considered it as a. division, which, 

 together with his division Orthorrhapha Nemocera, formed his sub-Order 

 Orthorrhapha. His sub-Order Cyclorrhapha I call Cyclorrhapha Athericera. 



"The three names of the sub-Orders which I adopt have the advantage 

 of being descriptive of a character taken from their metamorphoses on one 

 side, and of another character taken from the imago and its principal 

 organ of orientation (the antenna) on the other. The names Orthorrhapha 

 and Cyclorrhapha were very happily chosen by Brauer to characterize the 

 metamorphoses of each of the groups, and should therefore be preserved. 

 The names Nemocera and Athericera were adopted for two groups by 

 Latreille, and should likewise be retained. Finally, the name of Ortho- 

 rrhapha Brachycera was used by Brauer himself for a division which I 

 consider as a sub-Order. The position of the Pupipara I leave an open 

 question. 



"The arrangement which I conceive at present is, therefore, as follows :— 



I. — OrthoTrbapba Nemocera. 

 11. — Orthorrhaplia Brachycera. 

 III. — Cyclorrbaplia Athericera. ' ' 



