THE ENTOMOLOGIST. 37 
Figs. 5 & 6.—Mycetophila. Macrocera. 
The above figures, and others which will follow, are from 
the drawings of A. H. Haliday. The same letter refers to the 
same parts in all the figures. 
One of the chief attractions in noticing the Diptera is the 
great variety of their manner of flight, and this corresponds 
with the difference of structure in the wings. These variations 
will be briefly traced in some notes, which are preceded by 
the following extract from the MSS. of A. H. Haliday on the 
same subject. 
“The subcostal areolet lies between the costal vein and the 
first longitudinal vein, usually the mediastinal (but if this vein 
is effaced, then the subcostal). 
“ The mediastinal areolet lies next beyond this, between the 
mediastinal and subcostal veins; and if the mediastinal vein 
is wanting there is no mediastinal areolet. 
“ The radial areolet lies between the subcostal and radial 
veins; if the latter divides into two branches at the end, 
another radial areolet is enclosed between them; and in 
either case, if the radial vein is connected with the subcostal 
bya transverse vein, the radial areolet may be thus divided 
into more than one. This areolet may become entirely closed 
without extending to the margin, in case the radial vein 
rejoins the subcostal before the end, as in Laphria, Volucella, 
Hirmoneura, and Midas. 
