202 



THE WINGS OF NEUROPTERA 



state of our knowledge of the subject at a time when this volume was about 

 to be sent to the printer, when I made a reexamination of a series of 

 myrmeleonid wings which revealed the explanation of the problem. This 

 explanation is as astonishing as it was unexpected. 



Media of the hind wings in these insects is two-branched and there is no 

 anastomosis of vein Ms +4 with cubitus as there is in the fore wing. The 

 medial fork is very near to the base of the wing; and what has been 

 believed to be the cubitus is vein M3+4. I had observed the medial fork 

 but had regarded it as the result of the coalescence of veins M and Cu; and 

 had explained in the same way the forking of the medial trachea which I 

 had observ^ed in the hind wings of pup« (Fig. 195). 



Fig. 199. — Hind wing of Symmatheles contrarins . 



In wings mounted for study, as they are commonly mounted, the radial 

 fork is concealed in many cases by an overlapping of it by the radius, due 

 to a fold in the wing; but with a little care it can be easily seen. In the 

 hind wing of Brachyueniurus represented by Figure 198 the medial fork is 

 overlapped by the radius; the figure is a reproduction of a photograph and 

 it represents the veins as they appear when seen from above. Figure 199 

 represents the base of a hind wing of Symmathetes contrarins; in this wing 

 the forked condition of the media is obvious. 



Cubitus of the hind wings. — A study of the cubitus of the hind wings 

 confirms the conclusion regarding media given above, as in certain fonns 

 one finds a typical cubitus which is distinct from the vein that has been 

 believed to be the cubitus and which is really vein M3+4. 



In the hind wings of most myrmeleonids, as in the fore wings, vein Cu2 

 is greatly reduced, but a series illustrating different degrees of this reduction 

 can be easily found. 



