THE WINGS OF MYRMELEONID.^ 



197 



of the principal wing- veins of these insects; but I am convinced that at last 

 this problem is solved; and now that it is solved, it seems a comparatively 

 simple one, so simple that there can be no doubt as to the correctness of the 

 conclusions. The causes of the earlier and incorrect conclusions are 

 indicated in the following discussion. 



The determination of the identity of the costa, subcosta, radius, and the 

 radial sector presents no difficulties, and no change in the commonly 

 accepted view regarding these veins is necessary. This is true of these 

 veins in both the fore and hind wings. With regard to the other principal 

 veins it is necessar}^ to discuss the fore and hind wings separately 



Media oj the fore wings. — In the fore wings media appears to be a single 

 unbranched vein; but it has been demonstrated, by a study of the trachea- 

 tion of the wings of pupae, that what appears to be an oblique cross-vein 

 and which is lettered o in the figures, is a branch of media, and consequently 

 that media of the fore wings of ant-lions is two-branched, as it is in most 

 other Neuroptera. 



The significance of the oblique vein in the fore wings of myrmeleonids 

 was first discovered, twenty years ago, by Dr. Needham and myself, by a 

 study of pupal wings, when we were collecting material for our series of 

 articles on the wings of insects. We did not include our myrmeleonid 

 material in that series of articles, as it was not needed to illustrate the 

 fundamental principles that we were discussing; but I made use of it a 

 little later in a laboratory manual;* and Figure 194 is based on a photo- 

 micrograph that we made at that time. Recently Tillyard has studied the 



Fi<^. 192. — Wings of Myrmdeon, sp. From Katihar, British India. 



tracheation of the wings of myrmeleonids and discovered independently 

 that the media of the fore wings is two-branched (Tillyard 1916, p. 739). 



*The Elements of Insect Anatomy by John Henry Comstock and Vernon L. Kellogg, 

 Third Edition 1901. On page 116 of this work I indicated the significance of this 

 bUque vein. 



