422 Osten Sacken: on the eharaeters o/the three divisions of 



Antido.rion concludcs triuniphantly: „It is niy agreeable duty to 

 bi'ing betöre tlie Acadcmy thc proof that tho subdivision in (lucstion 

 is untenable in future"! About the palpi; not a word! 



Brauer, in bis writings since 1880, niaintains tlic division Or- 

 torrhapha Netnocera, but, like bis predecessors he neglects the 

 palpi in defining its character. In the dichotoniic table (Z. K. M. 

 I, p. 7, 1880) \ve find the usual perfunctory mention: „Taster selten 

 kurz und drei-gliedrig, meistens lang, drei- bis fünfgliedrig". But in 

 the long discussion about the limits between Nemorera and Brachy- 

 cera in Brauer's „Systematisch Zoologische Studien" (Sitzungsberichte 

 d. K. Akad. d. Wiss. 1885, p. 406—416) the palpi are not men- 

 tioned at all. In the Z. K. M. III, p. 9 Brauer goes so far as to 

 say: „Mögen die Dipterologen, der Bequemlichkeit wegen, auch heute 

 noch von Nemoceren und Brachyceren sprechen, derlei natür- 

 liche Gruppen giebt es nicht, und man ist auch nicht im Stande, 

 natürliche Charactere für sie aufzustellen" etc. (Compare the whole 

 passage.) 



That, in somo earlier geological times there existed a connection 

 between the two large groups of Diptera is very probable. But it 

 is necessary to recognize and to maintain, as an important contri- 

 bution, not only to the systematic arrangement of the Diptera, but 

 also to their geological history, — that up to the present time, including 

 even the accessible fossils, such transition-forms have not been dis- 

 covered. 



We may therefore safely use the following formulae for distin- 

 guishing the two divisions: 



I. Palpi generally four-, or five-jointedj), pendulous, and more or 

 less filiform; antennae niany-jointed (more than six-jointed), 

 generally filiform (seldom pectinate), with the majority of the 

 joints of the flagellum of a homologous structure..?) 



Nemocera Latreille. 



i) It is very propable that the palpi, in niost cases, are only ap- 

 parently five jointed, the basal Joint representing the raaxilla, or a por- 

 tion of it. Thus Westwood, Introd. II, p. 514, says: „It appears to me 

 from a careful examination of the structiire of these organs in Tipula 

 oieracea, that the first, or basal Joint is the analogue of the maxilla." 

 Westwood adds, 1. c, p. .525: „its texture is diflferent from that of the 

 palpus." Becher, Mundtheile, p. 9 calls it: Taster sc huppe. (See 

 in the Additions.) 



2) In this paper I have used the word homologous in its ordinary 

 sense, as „having the same relative position, proportion, value, or struc- 

 ture" (Webster's Dictionary), and not in tlie narrower sense, nsed by 

 zoologists: for instance that the hand of man and tlie fore-foot of a 

 horse are homologous. — Observe that the joints of a flagellum, for 

 being pectinate, do not cease to be homologous. — 



