THE ENTOMOLOGIST. 101 
Fig. 11.—Sciara. 
Fig. 12.—Bibio. 
THE inspection of the wing of a fly is generally sufficient 
to ascertain the genus of the individual to which it was 
attached, and there is much interest in tracing the great 
variation of the wing-bones of Diptera, and in observing how 
many changes are effected by the modifications of a few 
parts of the structure. Strength and swiftness of flight is 
generally accompanied by many wing-bones, but in numerous 
cases the bones are many, and the flight is very feeble. Ina 
few groups some of the bones are very slender, so as to be 
termed secondary. This is more conspicuous in some 
Hymenoptera, such as Chalcidiz, when the fore wing has 
generally only one bone near the costa, but in the largest 
species one or two diffuse veins or incipient bones in the 
disk may be indistinctly traced, The return of mild or warm 
weather and the morning sun impart much vivacity to the 
wings by means of electric currents through the bones, and 
recal the Diptera from a torpid state, like as comets become 
developed and move more rapidly when they approach 
the sun. . 
Five of these six figures, and the preceding six in the 
‘Entomologist, pp. 36, 87, represent the wing-bones of 
Mycetophilide: this family forms two divisions, Myceto- 
philini and Sciarini, of which the first includes seven 
sub-families,— Diadocidine, Mycetobine, Boletophiline, 
