[Berliner Entomolog. Zeitschrift Bd. XXXVII. 1892. Heft IV.] 417 



On the characters of the three divisions 



of Diptera: Nemocera vera, Nemocera 



a n o m a 1 a and Eremochaeta, 



by 

 C B. Osten Sachen. 



Classes et genera naturalia, non sola instrumenta 

 cibaria, non solae alae, nee solae antennae con- 

 stituunt, sed structura totius, ac cujusque vel mi- 

 nimi discriminis diligentissima observatio. 



Scopoli, Introd. ad Hist Nat. 401. 1777. i) 



I. General surve}^ of the subject. 

 In a Short paper „Suggestions towards a hetter grouping of 

 certain families of the order Diptera" (Entomol. Monthly Magazine, 

 February 1891) I have proposed an arrangement of a portion of 

 the Diptera OrthorrJiapha which I believe to be more natural than 

 the groiipings previously introduced for the sarae families. I said: 

 „These attempts, first made by Schiner, and aftervvards developed by 

 Brauer-2) cannot be considered as successful. The reason is (as far 

 as the families which I intend to discuss in this article are concerned) 

 that these groupings were principally based upon a character of sub- 

 ordinate value, taken from the wings, and on another character of 

 doubtful iniportance, borrowed from the larvae, without sufficient re- 

 gard for the Organization and the affinities of the imagos. I believe 



i) I found this in Kirby and Spence, Introduction etc., Vol. IV, 

 p. 455. Compare the Addition s to the present article. 



2) Schiner, in the Verh. Zool. Bot. Ges., 1864, p. 211; Brauer, 

 in bis Characteristic der Hauptgruppen, etc. (in the Denkschr. K. Akad. 

 d. AViss. Vienna, vol. xlii, pp. 105 — 216); a short Synopsis of the same 

 arrangement in 1. c, vol. xliv, p. 43 (99); a modified system, 1. c, xlvii, 

 p. 11; further developments in his Systematisch-Zoologische Studien 

 (Sitzungsber. d. K. Akad. d. Wiss. Vienna, 1885, pp. 237—413), and 

 in the Verh. Zool. Bot. Ges., 1890, pp. 273—275). 



Since 1880 Brauer published under the general heading: Die 

 Zweiflügler des Kaiserlichen Museums zu Wien, five cpiarto 

 volumes, each with a separate pagination. For brevity's sake 1 shall 

 quote them thus: Z. K. M. I, 7; III, 10 etc. which refers to the voiume 

 and the separate pagination. 



XXXYII. Heft IV. 27 



