150 [J"iy. 



Athericera were adopted for two groups by Latreille, and should 

 likewise be retained. Finally, the name Orthorrhapha BracJiycera 

 was used by Brauer himself for a division which I consider as a 

 sub-Order. The position of the Pi(,pi'para I leave an-open question. 



Within the three sub-Orders there are groups of Families which 

 I called divisions, and of which I characterized two in the sub- Order 

 OrtJiorrhapha Nemocera, and one in the Orthorrha'pha JBrachycera. 

 Future workers will perhaps succeed in grouping the remaining 

 Families in the same way ; until this be done these Families can be 

 retained in statu quo ante. 



The arrangement which I conceive at present is, therefore, as 



follows : — 



I. — Oethoeehapha Nemocbea. 

 Nemocera vera. 

 Nemocera anomala. 



II. — Oethoeehapha Beachyceea. 

 EremochcBta. 



III. — CxCIiOEEHAPHA AtHEEICEEA. 



One more word about the division Nemocera anomala. I called 

 it artificial for want of a better expression, although the Families 

 which compose it are connected by characters of the utmost im- 

 portance {I.e., p. 429 at the top), most of which never occur in the 

 Nemocera vera. Only the grouping of these Families is less compact 

 than is the case in the N. vera, the gaps between them are broader, 

 and the transitions less apparent. But it may happen that further 

 discoveries will bridge over these intervals, and convert this division, 

 now somewhat artificial, into a compact or natural one. The opposite 

 case may also happen : that future discoveries may necessitate a 

 further sub-division. Or we may admit a still different possibility ; 

 that the transitional forms are, at present, entirely extinct, but that 

 in earlier epochs the division was a natural one. The characters of 

 the Families which compose the division N. anomala do not exclude 

 any of these possibilities. At any rate, it is evident that such an 

 artificial or provisional division is indispensable for the present. It 

 has nothing in common with a mere grouping of Families or Genera 

 incertcB sedis, which have no connection whatever between them. 



Heidelberg : June 1st, 1893. 



