» 108 NATURAL HISTORY OF WASPS. 
here, and these little spaces and wandering lines 
have more than one set of names. The second and 
third of these cells, counting from the root of the wing, 
are the most important; their shape, their proportions — 
to each other, and their connection with the various 
nervures being points to be specially attended to. 
The third cell is irregularly quadrilateral. The 
second is uregularly hexagonal; it is in contact 
with the marginal cell already described, by a broad 
surface, not by a narrow neck ; and its bounding line 
inosculates with two lines called the recurrent ner- 
vures, as well as with the line which bounds the first 
cubital or sub-marginal cell. To assure ourselves of the 
reality of these distinctions, and to fix all these details 
exactly in the memory, we should compare the wing of 
a wasp with that of a bee, or with that of any of the 
little wasp-like insects which we may find in flowers. 
These nervures are the frame-work over which the 
membrane of the wing is spread. They give strength 
and direction to its blow, and radiating backwards 
from the root of the wing, assist in its feathering. 
The nervures are, or were in their first development, 
essentially air-tubes, and, as such, are lined with a 
spiral thread, which may be traced in some of the fine 
ramifications in a modified form. At the root of the 
wing, where they are gathered together to form the 
articulating surface on which the wing moves, they 
are thickest, and from this point they fade away till 
they are lost in the membranous expansion near the 
edges. The root of the fore-wings is covered in front 
by a small membranous scale called the tegula or 
wing-cover. The hind wings have no tegule, and are 
not folded in repose like the fore-wings. 
