268 THE WINGS OF THYSANOPTERA 



vein is termed the "ring vein" by writers on this order, although the term 

 ambient vein has been long in use for veins in this position. 



There is a short longitudinal vein separating the anal and preanal areas 

 (Fig. 265, A) ; this is doubtless the anal vein. Between the costa and the 

 anal vein, there are only two longitudinal veins (Fig. 265 i? and Cu); of 

 the four longitudinal veins that typically traverse this area, the subcosta, 

 radius, media, and cubitus, the radius and cubitus are almost invariably the 

 more persistent when there is a reduction of the wing venation. I therefore 

 conclude that these two veins are the radius and the cvibitus respectively. 

 These two veins have been designated as the anterior longitudinal vein and 



Fig. 266. — Fore wing of Ervthrolkrips arizonce 

 (After Moulton). 



the posterior longitudinal vein respectively; but it is obvious that terms 

 that pertain to the uniform terminology are preferable so long as there is no 

 reasonable doubt as to the homologies of the veins. 



In some members of the order there are a few veins extending trans- 

 versely to the length of the wing. It is possible that these are branches of 

 the longitudinal veins that have become transverse by a coalescence of their 

 distal portions with adjacent veins; but in the absence of any data to 

 confirm this suggestion, it is better to designate them simply as cross-veins. 

 A good illustration of this type of wing is that of Erythrothrips arizoncB, 

 figured by Moulton ('11) (Fig. 266). 



