THE WINGS OF NEUROPTERA 



161 



sector, no instance has been observed in the Neuroptera in which there is 

 such an appearance at the proximal end of the series. The only possible 

 exception to this statement is that it is conceivable that in the development 

 of a radial ctineate area vein R.^ may be split to its base and in this way an 

 addition to the nimiber of branches of the radial sector be made at the 

 proximal end of the series. 



As a nile, in the development of a radial cuneate area vein Rj is not 

 split back far enough to warrant this suggestion ; but in Rapisma (Fig. 171) 

 and in Megalomus (Fig. 178) the splitting back of vein R.5 has progressed 

 nearly to the base of this vein. 



I know of no near allies of Rapisma, but Megalomus can be compared 

 with more generalized members of its family, as Hemerobius, in which there 



rca 



Fig. 156. — Wings of Acanthaclisis; a species from the Seychelles Islands. 



is no indication of accessory veins being added to the proximal end of the 

 series. 



It seems worth while to make this extended discussion of this question, 

 for the chief object of the uniform terminology is to apply the same term 

 to homologous veins, in order that affinities between different groups of 

 insects and differences in methods of specialization can be more clearly 

 indicated. This end would be defeated, so far as the evidence presented 

 by the radial sector is concerned, if the numbering of its branches begins at 

 the wrong end of the series, that is at the distal end. 



In those families in which the accessory veins of the radial sector are 

 added only distally, thus forming a regular series, and this appears to be the 

 case in most of the families, the first branch of the radial sector is vein R5, 

 and following this in regular order are veins R4, R;j, Ro.j, Rjb, and so on to 

 the end of the series of definitive accessory veins. 



