6c>4 
THE STUD Y OF INSECTS. 
spect the homologous veins in the Lepidoptera and Diptera. In the 
Hymenoptera the tips of the branches of vein III coalesce with 
other veins; and when this coalescence has proceeded for a con- . 
siderable distance towards the base of the wing, the branches may 
appear like cross-veins, instead of branches of a longitudinal vein. 
This result is very similar to what takes place in the more specialized 
Diptera. In Pamphilus (Fig. 733) vein 11 In is wanting; but this vein 
is present in Macroxyela (mac-rox-y-e'la) (Fig. 735 )* km* 1 of 
these genera there is a cross-vein between veins 111 1 and Illa+a (Fig. 
733, cv ). A similar cross-vein exists in some crane-flies, dividing cell 
Fig. 733.—Wings of a saw-fly, Pavj/>hilius y with the veins numbered. 
IIIi into two parts (see Fig. 505). In both of these genera also the 
tips of veins III« and III 6 coalesce with vein Vi to such an ex¬ 
tent that these veins appear to be cross-veins. In the wing of the 
Honey-bee (Fig. 730) these veins are more obviously longitudinal 
veins. 
Vein V is very similar to the homologous vein in the Diptera. It 
arises from a cross-vein extending from vein III to vein VII. In 
Pamphilius it arises from near the costal end of this cross-vein; but 
in Apis (Fig. 730) its origin is near the middle of the cross-vein. In 
the Hymenoptera, however, the cross-vein 111 —V 11 is much farther 
from the base of the wing than it is in the Diptera. In the more 
