72 Osten Sachen: on (he atavic index- characters 



this genus (P. aberrans), as a doubtful form, a few pages off in the 

 genus Rhamphidia (1. c. p. 43). All these variations notwithstanding 

 the Peripheropterae, as belonging to the section Limnobina, 

 have neither spurs, nor empodia. 



Another tropical form of the section Limnobina has the wings 

 developed just in the'opposite direction; the distal half is very much 

 cnlarged, and the veins and cells in it are singularly elongated and 

 curved. This is the genus Libnotes Westw. (Trans. Ent. Soc. London 

 1876, p. 505, Tab. III, fig. 6 b) occurring in Ceylon, the Moluccas, the 

 Philippines, New Guinea and Queensland. About the location of this 

 genus two distinguished entomologists were doubtful. The author of 

 the genus, West wo od, said: „It is not easy to speculate on the 

 near affinities of so anomalous an insect." V. d. Wulp (Tijdskr. etc. 

 XXI, p. 196, 1877) says: „It seems to nie that the forked radial vein, 

 the microscopic pubescence at the end of the longitudinal veins, and 

 the absence of spurs on the tibiae prove conclusively that the place 

 of this genus is among the Eriopterina, where, on aceount of its 

 aberrant form, it should be placed either at the beginniug, or the 

 end of the series." The vcnation, in this case, has not been correctly 

 interpreted: the radial (or second) vein is not forked, and therefore 

 there is only one submarginal cell. But even without regard to the 

 venation, if we simply refer to the formula which I have given above 

 for spurs and empodia, we find at oncc the natural place of Libnotes: 

 it has neither spurs. nor empodia, and therefore it belongs to the 

 Limnobina. This location is fully justified by the other characters 

 of Libnotes: it has but one submarginal cell, 14-jointed antennae, 

 the ungues dentate on the underside, the forceps of the male has a 

 structure characteristic of a true Limnobia etc. The Eriopterina, 

 on the contrary, are provided with distinct empodia, have two sub- 

 marginal cells, 16-jointed antennae etc. Thus we have in Libnotes 

 a new proof of the efticacy of spurs and empodia as trustworthy 

 index-characters. (In my Studies etc. II, p. 179— 183, Berl. Ent. Z. 

 1887, I have published a detailed account of the genus Libnotes, 

 with an analytical table for thirteen species.) 



In Vienna I have seen a Peripheroptera which, in the elongation 

 of the veins and cells of the distal half of the wings, shows sume 

 approach to Libnotes (Studies, 1. c. p. 176). 



The genus Dapanoptera, from New Guinea, with its peculiarities 

 in the venation and its beautiful coloring, can, on the same principles, 

 be easily proved to belong to the Limnobina (Studies, I.e. p. 178). 



Many tropical forms of Tipulidae will be discovered yet, showing 

 rather intricate venations, where contortions and coalescences of veins 



