128 THE ENTOMOLOGIST. 
Fig. 23.—Orphnephila. 
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Fig. 24.—Dixa. 
In Sciara the nearness of the cubital bone to the costa is 
apparent, and there is a transition through some intermediate 
forms between this genus and Cecidomyia, where the bones 
mostly disappear. In Bibio the arrangement of the bones is 
quite changed, and the new pattern is continued in the two 
following genera, Plecia and Penthetria (figs. 13, 14), where 
the cubital is forked. Penthetria differs chiefly from Plecia 
in the shortness of the radial, and in the junction of the first 
branch of the cubital with the costa, and not with the radial. 
In Scatopse (fig. 15), which is the type of the second division 
of the Bibionidz, the cubital is again near to the costa, and 
is joined by a transverse bone to the first._branch of the pre- 
brachial, and there is an undulating subaxillary. In Aspistes 
(fig. 16) the structure is much more simple, and A. H. Haliday 
remarks that its analogy to that of Scatopse is very doubtful. 
In the Chironomide (figs. 17, 18) there is another plan in the 
formation of the bones: neither the cubital nor the prebrachial 
is forked, and the anal extends to a greater distance from 
the base of the wing ; the hovering flight and the great swarms 
of some kinds of this family are well known. In Culex (fig. 
19) another change occurs: the longitudinal bones are more 
numerous, and the passage from it by Phlebotomus (= He- 
masson, fig. 20) to the little moth-like flies (figs. 21, 22), whose 
abundance and feeble flight are well known in this country. 
I have placed Orphnephila (fig. 23) with the Chironomide, 
and Dixa (fig. 24) next to the Tipulide, as the formation of 
the wings agrees generally with that of Limnobia and of the 
neighbouring genera. 
Francis WALKER. 
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