H YMENOP TER A. 
605 
generalized Hymenoptera vein V is three-branched, and veins V a and 
V 3 are connected by a cross-vein, as in the Diptera ; but this cross¬ 
vein appears like a longitudinal vein (Fig. 733). The tip of vein V 3 
has migrated from its primitive position on the outer margin of the 
wing to the anal furrow (vein VIII), and ends in this furrow at a 
greater or less distance from the margin of the wing (Fig. 733); the 
result of this migration is to pull the cross-vein V a -V 3 into a longi¬ 
tudinal position. 
Vein VII coalesces with vein III for a considerable distance from 
the base of the wing in Pamphilius (Fig. 733) ; but in Apis (Fig. 730), 
and in many other forms, it arises from the base of the wing. This 
vein is two-branched, as in the Lepidoptcra and Diptera. The tips 
of the branches of vein VII have migrated from the margin of the 
wing to the anal furrow (vein VIII), and for a considerable distance 
along this furrow towards the base of the wing, so that both of these 
veins (VIIi and VII 2 ) end in the anal furrow, far from the margin of 
the wing; the result of this migration is to pull the cross-vein 
V 3 -VIIi into a longitudinal position. In Pamphilius (Fig. 733) this 
cross-vein is nearly longitudinal; in Apis (Fig. 730) it is completely 
so. In Pamphilius vein VII a is very short, but well enough de¬ 
veloped so that there is no doubt regarding the homology; but in 
most Hymenoptera it has completely disappeared. 
In the area lying back of the anal furrow there also exists a 
tendency for veins to coalesce at their tips ; this is well shown in both 
fore and hind wings of Pamphilius ; and in the hind wings especially 
the united tips of veins IX and XI have migrated towards the base 
of the wing along the anal furrow (Fig. 733). 
The concave veins of the anal area (veins X and XII) are rarely 
developed ; in the hind wing of Pamphilius there is a fold which 
probably represents vein XII (Fig. 733). 
The Cells of the JVi;tg. —Having learned the venation of the wings 
it is easy to number the cells. There are, however, a few special 
terms that are used in works on this order; the more important of 
these are the following: — 
In most Hymenoptera there is an opaque spot on the costa, a short 
distance beyond the middle of the wing; this is the stigma (Figs. 734 
and 735, s ). The stigma lies between vein 111 1 and the margin of the 
wing ; it is probably the apical portion of cell II. In Figure 733 it has 
not been blackened in order to show the course of vein IIIi. 
Usually vein 111 1, after joining the costa at the end of the stigma, 
does not again separate from it, but is joined by the tip of vein III 3 
before the apex of the wing (Fig. 733). But in certain families the 
