XX.xii, '21] F,.XTO.MOI.nr,!CA!, NEWS 1 ( >3 







would assume -the position of the vein bearing these labels in 

 Fig. 2. I would therefore maintain that the veins extending 

 almost parallel to each other down the center of the wing 

 shown in Fig. 2 represent the radius ( R } and the media plus 

 cubitus (M+Cn), and therefore the corresponding veins in 

 the Thysanopteron shown in Fig. 1 would also represent the 

 radius ( K ) and the media plus cubitus (M + Cu). The veins 

 labeled A in Figs. 1 and 2, evidently represent the anals, as 

 may be seen by comparing them with the anals (1st A and 2d 

 A} in Fig. 8. 



In Fig. 3 is shown the venation of a primitive fossil Thy- 

 sanopteron, Palaeothrips fossilis, in which there extend from 

 the veins R and M+Cu four large vertical veins connecting 

 them with the margins of the wings. These vertical veins 

 correspond to the small veins which have been dotted in Fig. 1, 

 since they do not occur in the Thysanopteron there figured, al- 

 though they do occur in many other recent Thysanoptera. Judg- 

 ing from the size and greater importance of these vertical veins 

 in Fig. 3, I am inclined to regard them as modified branches of 

 the longitudinal veins, rather than as mere cross veins, although 

 in the recent Thysanoptera (Fig. 1) they have become greatly 

 reduced, and are of relatively slight importance. A compari- 

 son of Fig. 3 with Fig. 4 would indicate that the veins labeled 

 Rl and Sc in Fig. 3 may represent portions of R\ and Sc of 

 Fig. 4, which have become bent forward and have assumed 

 a vertical position. The interpretation of the veins labeled 

 Cul and Cit2 in Fig. 3, however, is more difficult. The vein 

 labeled M in Fig. 3 is clearly M, or a branch of it (i. e., 

 Ml'^2) ; but the vein labeled Cu\ in Fig. 3 seems to 

 represent a branch of M (i. e., M3+4) instead of represent- 

 ing the vein indicated by the label it bears. In the Zorapteron 

 shown in Fig. 5, vein Citl has become detached from Cu2 

 through the partial fading out of the base of Cul (indicated by 

 the dotted line) and if this process were continued until only 

 the portion of Cul extending from the vein* labeled UI-CH to the 



* It might he argued that the vein labeled in-cu in Fig. 5 represents 

 KI2+3 (and that the vein labeled M represents A/1 +2) ; but a glance 

 at the figure of the fore wing of Zorotypus hubbardi by Candrll, 1920, 

 will show that there is no connection between the veins labeled M and 

 Cul in Fig. 5 in Caudell's figure, and since M and C id are not > 

 nected, it is hardly possible that Cul should contain a branch of M. 



