Empididae. 29 



by the quite simple hind legs and the slightly hairy legs; spuria by 

 the short and somewhat robust, more hairy legs, slightly thickened 

 hind tibiæ, but simple hind tarsi ; intermedia by the medium-long legs, 

 the longer-haired femora and the slightly thickened two joints on the 

 hind tarsi; besides the female has light balteres; nigra has still longer 

 and more slender legs, the hind femora have still longer hairs, and 

 the first two joints on the hind tarsi are eonsiderably thickened; also 

 it differs in the whole colour, the paler hairs and clearer wings, and 

 the paler balteres in the male ; pilosa fmally is recognised by its 

 strong pilosity and the colour of abdomen in the male. — bi a histor- 

 ical sense it is not uninteresting to note, that the species of Bybos by 

 the use of varyingand not valid characters have been divided into more 

 species than really exist, while on the contrary the species of ^^e/^ana, 

 distinguished by characters which are to be sure small, but good, 

 have remainded unrecognised. For the rest there are several indica- 

 tions in the literature, showing that the authors have felt, that the 

 species were not satisfactorily treated ; thus Scholz (Zeitschr. f. Entom. 

 Breslau, V, 1851, 60) says, after having enumerated spuria and nigra: 

 „Die Cyrtoma - Arien bediirfen jedenfalls noch einer genaueren Aus- 

 einandersetzung", and Zetterstedt says under nigra: „specimina sub 

 hoc nomine a D. Stæger e Dania communicata, pedibus nigris & 

 metatarsis parum incrassatis, potius, ut mihi videtur, ad Cyrt. spuriam 

 referenda". As remarked above these specimens helongedio intermedia 

 and Zetterstedt's expression shows, that at the same time as he recog- 

 nised them as not belonging to nigra, he was also not certain in re- 

 ferring them to spuria. Strobl (Mitth. Ver. Steierm. 1892, 43) gives 

 some notes about spuria and nigra, but when he says, that nigra 

 bas „einen weisslich behaarten Hinterleib" this is not quite correct, 

 the hairs are more or less pale but not white; about nigra he says 

 that the two first joints of the hind tarsi are eonsiderably thicker 

 than the following, but then he continues: „doch ist auch hier bei 

 reifen Exemplaren die Verdickung wenig auffallend" ; I think such 

 specimens may have been intermedia which has always darker legs 

 than nigra, and therefore the author takes these specimens to be 

 quite mature. All specimens of nigra I have seen have had very 

 distinctly thickened joints. In Schiner's descriptions there seems to 

 be some confusion, as he ascribes nigra blackish and spuria brownish 

 wings; moreover he says about spuria: „die Art ist nach meinen Er- 

 fahrungen, Meigens Angaben entsprechend , immer etwas grosser", 

 and he gives for nigra IVa", for spuria P/'-t — 2", whereas nigra in 

 reality is the largest; Meigen gives also for spuria (atra) IV2" and for 

 nigra 2". 



