102 THE ENTOMOLOGIST. 



Macvocerinae, Ceratoplatinae, Sciophilinae, and Mycetophi- 

 linae. Mycetobia (sub-fam. 2) differs especially from Diado- 

 cidia (sub-fam. 1) in the much greater length of the subcostal, 

 and in the nearer approach of the radial to the tip of the 

 wing. Ditoniyia (sub-fam, 2) differs from Mycetobia in the 

 incomplete and very short subcostal, in the forked cubital, 

 and in the much longer fork of the prgebrachial. In Platyura 

 (sub'-fam. 5) the subcostal is complete but short, the radial is 

 much shorter than that of the Ditomyia, and the fore fork of 

 the cubital is very short. In Bolitophila (sub-fam. 3) the 

 subcostal is elongated, the fore fork of the cubital is as short 

 as that of Platyura, but joins the radial near the tip of the 

 latter; the first pobrachial is much longer than in any of the 

 preceding genera. In Macrocera (sub-fam. 4) the subcostal 

 and the radial are shorter, and the very short fore fork of the 

 cubital is beyond the tip of the radial ; the curve of the 

 cubital also distinguishes this from all the preceding genera. 

 In Sciophila (sub-fam. 6) a greater change occurs in the 

 structure of the bones ; the cubital has two short approximate 

 directly transverse forks, which join the radial. In Tetrago- 

 neura, belonging to the same sub-family, the structure is still 

 more altered; the subcostal is incomplete, and very short; 

 the radial and the cubital are gathered closer to the costa, 

 and the two forks of the radial are shorter and more approxi- 

 mate than in Sciophila, and the two branches of the 

 pobrachial are much nearer to the tip of the wing. In 

 Gnorista and in Mycetophila (sub-fam. 7) the cubital is 

 simple, and the arrangement is much like that of Diadocidia 

 and of Mycetobia, excepting the peculiar curved radial of the 

 latter. In the Mycetophila, here figured, there is no sub- 

 costal, and the prajbrachial does not form two branches. In 

 Sciara (div. Sciarini) the resemblance to Tetragoneura is 

 apparent; the radial and the cubital are curved near the 

 costa; the other veins are slight or secondary, and the 

 praebrachial does not form two branches. There is a transi- 

 tion from Sciara to Cecidorayia when the veins are very few; 

 but these notes are limited to the figures which they accom- 

 pany. The flight of all the preceding genera is feeble, short, 

 and flitting; that of Bibio (fam. Bibionidae) is hovering, and 

 of long continuance, and there is another plan in the con- 

 struction of the wing-bones. 



Francis Walker. 



