bibiohid.t;. loy 



or less incurved, both joints usually highly pubescent. Ovipositor 

 of female withdrawn or very sliort, ordinarily only a pair of 

 small lamellae visible. 



Legs relatively short and stout, compared with the usual nema- 

 tocerous type (except Simuliidve and Orphnephilid.e). Fore 

 tibiae sometimes ending in a strong spine (Bibio) or circlet of 

 spines (Diloplms) or without either (Scatopsin^). Three pulvilli 

 in BiBioi^iN.i:, one pulvillus only in Scatopsin.t;. Claws distinct. 



Wings comparatively large and wide ; costal vein not produced 

 round the hind margin, ending before the tip of the wing. Veins 

 on the anterior part of the wing much more distinct than on the 

 posterior half. Auxiliary vein and 1st longitudinal vein present : 

 2nd longitudinal vein absent,* third vein forked (Plecia) or 

 simple (Bibio, Dilophiis, Scatopse) ; 4th vein forked,t 5th vein 

 forked in Bibionincp, simple in Scatopsin^. The 6th and 7th 

 veins present in Plecia, 6th absent in Bibio ; only two veins 

 posterior to the 4th in Scatopse, it not being quite obvious which 

 one is absent. Schiner regarded them as the 5th and 6th, and 

 they are termed such in the present work. The 2nd basal cell is 

 present in the Bibioni:^^, absent in the Scatopsix-E ; anterior 

 cross-vein present in Plecia, Bibio, and Diloplms, very short 

 or hardly visible in some species of Scatopse, absent in others. 

 Posterior cross-vein present in BibioninjE, absent in (ScATOPSiNiE. 

 Anal lobe of wing prominent. 



Table of Subfamilies. 



A few leading characters separate the two subfamilies of 

 Bibionid^ very clearly, and they may be summarised as follows : — 



Second basal cell present; the 5th longitudinal 



vein forked ; posterior cross-vein present ; three 



pulvilli to the tarsi ; generally densely pubescent 



flies of moderate or comparatively large size . . Bibioninae, p. 160. 

 Second basal cell absent ; the 5th longitudinal 



vein simple ; posterior cross-vein absent ; one 



pulvilliform empodium present; always small 



flies, much less pubescent than in the previous 



group Scatopsinae, p. 179. 



* I am not at all sure that the 2ad longitudinal vein is not present, and 

 the 3rd vein absent, instead of vice versa. If we compare a wing of Culex 

 with that of Plecia, and simply ehminate the 3rd vein from the former and 

 lengthen the anterior cross-vein, we get an exact counterpart in the wing 

 of the latter. In Culicid.e the 5th vein is admittedly forked. Plecia, there- 

 fore, seems the nearest genus in the Bibionid.e to the Culicid.e. Besides, a 

 forked 2nd longitudinal vein is quite usual in the Nematoceka, but much rarer 

 in the Brachyceba, whilst the 3rd vein is seldom forked in the former. The 

 suggested interpretation is therefore more in keeping with the general rule in 

 Nematogeea, but it is only tentatively put forward. 



t Except in Aspistes, a non-Oriental genus, in which it is simple. 



