[Berliner Entoraolog. Zeitschrift Bd. XXXIX. 1894. Heft I.J 69 



On the atavic index-characters 



with some remarks about the Classification of the Diptera 



by C. R. Osten Sacken. 



In a notice of Mr. H. Krauss on the recent work of Mr. Brunner 

 von Wattenwyl: Revision du Systeme des Orthopteres etc. (Entom. 

 Nachr. 1893, p. 237) I found the following passage: 



„The perspicacity and talent for Observation of the author have 

 enabled hira to discover and to make use of often very recondite and 

 apparently insigniticant characters, taking but a very subordinate 

 part in the ordinary functions of the aniinal, and arrested in their 

 development, but which, for these very reasons, have a great phylo- 

 genetic importance, as indications of descent and relationship. Such 

 characters the author has used in defining the larger groups. The 

 biological characters on the contrary, playing an important part in 

 the life of the species, and variable in consequence of adaptation, 

 were used by him for the charactcrization of the gener a." 



I was greatly pleascd with this passage, because it reminded nie 

 that I had arrived at exactly the same result in the Classification of 

 the Tipulidae which I published in 1859, and, in a more developed 

 form, in 1869. i ) Finding now that the very same method is equally 

 useful in determining the Classification of Orders so widely different 

 as the Orthoptera and Diptera, my confidence in its efficiency 

 is naturally increased, and I feel impelled to give a somewhat detailed 

 account of my experiences in working it. 



The family Tipulidae, perhaps on account of the fragility of the 

 specimens, has always found little favor with dipterologists, collectors 



i) New genera and species of North-American Tipulidae with 

 short palpi, with an attempt at a new Classification of the tribe. — (In 

 the Proc. Acad. Nat. Sc. Philad. August 1859; 60 pages and two plates.) 



On the North-American Tipulidae Part first; Tip. brevipalpi. 

 — (In the Monographs of the Diplera of N. -America. Part IV; XII and 

 346 pages and four plates.) — Washington, Smithsonian Institution, 

 January 1869. 



