408 



THE WINGS OF INSECTS 



From a study of the fore wings of these two genera a diagram of a 

 typical hymenopterous wing can be made. Figures 425 and 426 represent 

 such a diagram ; in the former the wing- veins are lettered, and in the latter, 

 the cells of the wing. This diagram represents the venation of the fore 

 wing of Pamphilius, except that vein R2, which is lacking in this genus, 

 is added. 



The cell lettered S in Figure 426 is the pterostigma or stigma; it is cell 

 Sc2, but is designated as the stigma, on account of its usually being opaque 

 in many genera of this order. 



In the wings of these sa^vfiies the anal furrow and the median furrow are 



Fig. 424. — -Wings of Macroxyela. The cells are lettered. 



both well-marked; the anal furrow is immediately in front of the first anal 

 vein, and the median furrow is in front of the media. The furrows are 

 represented by dotted lines in the figures. 



In the anal area (i. e., that portion of the wing back of the anal furrow) 

 the three typical veins are preserved; but they coalesce to a considerable 

 extent, both at the base and near the margin of the wing. 



In the basal part of the pre-anal area {i. e., that portion of the wing in 

 front of the anal furrow) the stems of the principal veins are as follows : the 

 costa coincides with the costal margin of the wing (Fig. 425, C); the sub- 

 costa (Sc) is well preserv^ed and is forked; back of the subcosta is a strong 



