THE ENTOMOLOGIST. 41 



in which the pobrachial areolet Is prolonged open to the hind 

 margin (Sciophila, Tetragoneura, Leia, Gnoriste, Myceto- 

 phila, Cordyla) : this type extends from Sciara to Zygoneura 

 and Lestremia, and thence to Campylomyza and the Ceci- 

 domyiae, in which the simplicity of the veining least of all 

 admits or needs the application of the complicated nomeu- 

 clalure tliat may have been retained in the previous families. 

 The Bibionida), in general, may perhaps be best illustrated 

 by a comparison with the first type of Mycetophilidae (as 

 Platyura, &c.) ; see Rhyphus also ; while Scatopse seems not 

 remote from the second type of that family, and Aspistes 

 presents a case almost as hard to the assumed type as is that 

 of the Diptera Hypocera. 



"The Culicidse and Psychodini have the cubital vein 

 simple, the radial forked. The Tipulidse either have both 

 these veins simple (Limnobia, Rhipidia, Rhamphidia, Sym- 

 plecta, Idioptera), or the radial forked (Dixa), — Trichocera, 

 Anisomera, Limnephila, Tipula, Ctenophora, Pachyrina, Ne- 

 phrotoma, Erioptera, &c. In a very few cases (Ptychoptera, 

 Limnophila immaculata, &c.) the veins divide in such a way 

 that we must consider the radial as simple and the cubital 

 forked. In nearly all other cases, when either of these is 

 branched, it is the cubital, and this holds good among the 

 other Macrocera (as Mycetophilidae of the first section, and 

 some Bibionidce), as well as in the Brachycera. In 'I'ipula 

 and the allied genera — Pachyrhina, Nephrotoma, Megistocera, 

 Ctenophora — there are five externo-medial areolets, of which 

 two are behind the discal areolet, while in the rest, — Limno- 

 bia, Limnophila, Erioptera, Trichocera, Ptychoptera, &c., — 

 whether the externo-medial areolets be four or five, only one 

 lies behind the discal areolet (which is sometimes wanting). 

 Generally the anal areolet is open to the margin in the 

 Nemocera, though there are a few exceptions (Eriocera 

 nigra, Macq., and Limnobia Trentepohlii, Wied.), and closed 

 in the Brachycera, or nearly so ; and in the latter families 

 (Muscidae, &c.), small and distant from the margin. In 

 Cyhndrotoma, Macq. Dipt. pi. L f. 15, the subcostal vein 

 seems to reunite with the radial before the end, the usual 

 termination of the former being probably obliterated, and 

 what is elsewhere a transverse vein connecting the subcostal 

 and radial, here appearing as the termination of the former. 



G 



