312 



PSYCHE. 



[December 1895. 



Packard. In his most recent *vvriting 

 on the matter, Professor Comstock 

 states that in his present opinion it 

 would be well not to recognize pre- 

 media and postmedia as belonging to 

 the group of principal longitudinal 

 veins. 



As a note, perhaps of interest, I ofler 

 a brief account of certain observations 

 recently made on Ephemerid wings. 

 A comparison of the figures of Red- 

 tenbacher and Comstock show that 

 although both refer to a premedial and 

 a postmedial vein they differ in their 

 interpretations of what constitutes these 

 veins and their respective branches (see 

 figures I and 3, after Redtenbacher and 



of the venation of the Ephemeridae 

 agrees with Comstock's in that both 

 make radius (scapularis of Scudder. 

 after Heer) a simple (unbranched) 

 vein, but Scudder does not recognize 

 any independent longitudinal veins 



Fig. I. 



Comstock, respectively). What Pro- 

 fessor Comstock defines to be vein IV 

 and its branches includes part of Red- 

 tenbacher's vein III and all of his veins 

 IV, V, VI, and their branches. Vein 

 V of Comstock is Redtenbacher's vein 

 VII, and Comstock's veins VI and VII 

 are included by Redtenbacher among 

 the anal veins, t Scudder's description 



* Comstock, J. H., The Venation of tlie Wings of Insects, 

 pp. 75-91, in The Elements of Insect Anatomy, by Comstock 

 and Kellogg, 1895. 



t Scudder, S. H., The Pretertiary Insects of North 

 America, pp. 5-6. iSgo. 



Fig. 2. 



between radius and media or between 

 media and cubitus. Comstock's veins 

 IV and V are Scudder's externo-median, 

 and his veins VI and VII are Scudder's 

 interno-median. That is, Scudder 

 makes premedia a branch of media, and 

 postmedia a branch of cubitus. 



None of these interpretations of the 

 Ephemerid venation seems to me the 

 correct one ! The presumptuousness of 

 this statement should be less offensive 

 when we recall the fact that no two of 

 the three already ofiered interpretations 

 aoree. A characteristic of radius 

 noticeable in generalized wings and 

 strenuously preserved in the specialized 

 wings, is its branched condition. Just 

 as sub-costa is characterized by its uni- 

 formly unbranched condition (except- 

 ing in the wings of a few very 

 generalized insects, as the Blattidae), 

 and media is characterized by its 

 tendency to lose its basal half, so radius 

 and cubitus are characterized by the 

 persistence of their branches. Radius 

 in its mode of branching also shows 



