40 THE ENTOMOLOGIST. 
of veins and change in their direction, little difficulty arises 
from such anomalies as an additional transverse vein, such as 
subdivides the subapical areolet into two in Microdon, or the 
pobrachial in Idioptera. The Hypocera are hardly to be 
reduced with certainty to an analogous type, but the simpli- 
city of the veining and the contrast between the strong veins 
which end in the fore margin, and the faint ones (venule) 
which run to the hind margin, allow of and recommend 
a different and simple nomenclature. 
“ The Nemocera have a much greater variety in the veining 
of the wings, and there is not a little difficulty in accommo- 
dating to them the nomenclature used for the Brachycera, 
partly from the multiplication of longitudinal veins, as in the 
Psychodini, but yet more from the extreme faintness of the 
veins in many, as in Simulia, and the ultimate disappearance 
of all but one or two in the Cecidomyide. Still, apart from 
these extreme cases, we may observe such a degree of gradual 
modification of the veining in most as to be able to apply an 
analogous nomenclature to at least some of the principal 
veins, and by relation to them to denominate the rest; 
although it may be doubted whether it is not best to employ 
a different and simpler numerical nomenclature when the 
veins become few in number, and the closed areolets nearly 
null or insignificant. Rhyphus has been taken as the type 
by which to assimilate the nomenclature of the Nemocera to 
the Brachycera, as it is scarcely possible to overlook the 
analogy between Rhyphus and the Leptidz and allied families 
of the Brachycera. From Rhyphus the transition is not 
difficult to the Tipulidz, and thence to the Culicide. From 
the latter probably the Psychodini on the one hand, and the 
Chironomidz on the other, may be illustrated with sufficient 
probability. The transition from the Tipulide to the Myce- 
tophilide is more abrupt; and these last, in respect to the 
veining of the wings, not only undergo great diversities, but 
present two manifest types separated by as abrupt an interval. 
The first of these, characterized by the more or less complete 
coalescence of the prebrachial and pobrachial areolets (Boli- 
tophila, Thaumalea, Macrocera, Platyura, Ceroplatus, Dito- 
myia, Asindulum, Diadocidia, Mycetobia), still preserves most 
analogy to the preceding family. The second, in which these 
two areolets are separated by a strong prebrachial vein, but 
