300 
SYSTEMATIC ARRANGEMENT 
mum state of development, they are five in number. 
The longitudinal one placed along the anterior 
border of the wing, is usually called the costal 
nervure : it was named by J urine, who first gave a 
nomenclature to these parts, the radius, from a 
notion that it was analogous to the hone so named 
in vertebrate animals. For the most part this is the 
strongest nervure in the wing, as it forms the ante- 
rior edge when that organ is extended, and has, 
therefore, to cut through the air during flight. The 
nervure next to this, and running parallel with it, 
is the sub- costal nervure, — the cubitus of Jurine. 
Both these terminate in an opaque expansion on the 
anterior border of the wing not far from the middle, 
which is called the stigma, a term which has been 
appropriated to a totally different part of structure, 
but is now in too general use in its twofold sense 
to be disturbed. The sub-costal gives off, a little 
before its origin, a third nervure, which runs almost 
in a direct line towards the centre of the wing, and, 
at a longer or shorter distance from its commence- 
ment, describes numerous zigzag lines; this it has 
been proposed to call the medial nervure. Beyond 
this a pretty wide area usually intervenes, which is 
bounded posteriorly by a nervure running somewhat 
obliquely towards the centre of the hinder border, 
which has received the name of sub-medial. The 
last is more slender than the rest, and has been 
very appropriately called the anal nervure. 
The nervures just described are always more or 
less united by transverse and recurrent nervures. 
