ADDITIONAL NOTES ON TRICHOCNBMIS ALIEN A 



SCUDDER. 



By Richard A. Muttkowski. 



The foregoing notes were transmitted to me by Dr. Ris in a 

 letter and are published with his permission. I believe, that there 

 is little more than can be said on Stenogomphus carletoni. The 

 remarks on T. aliena were, however, of such interest that I began 

 a comparison of the figured specimen with living genera. 



The species has been repeatedly discussed. The crucial point 

 of all these discussions has been the additional cross-vein in the 

 subquadrangle. But, as stated by Dr. Ris, this is anomalous or 

 due to an error by the artist. I incline to the latter assumption. 

 For it is not to be expected that Scudder would omit mention 

 in his text of such an unusual feature as an additional cross-vein 

 in the subquadrangle. Hence it is rather to be assumed that the 

 drawing is inaccurate, as, in fact, already instanced by Dr. Ris 

 for Stenogomphus. Furthermore, another specimen obtained by 

 Mr. Cockerell shows no indication of an additional cross-vein. 



In a published correspondence between Prof. Cockerell and 

 Mr. Williamson, 1 the following relationships were considered 

 (besides thePlatycnemis supposition, which Williamson also ques- 

 tions) : 



a) The vertical subnodus, which would ally T.aliena to Owyagrion, 

 Argia, Hyponeura, and Ischnura (partly). Mr. Williamson does not 

 regard this as indicating generic relationship. 



b) Allied to Hesperagrion because of similarity of wing form, 

 quadrangle and subquadrangle, and the relation of their parts to the 

 antenodals, the origin of INI, ; also "the length and direction of the 

 subnodus are not far out of the way." 



c) To which may be added those given by Dr. Eis : Amphiagrion, 

 Antiagrion, and the Hawaiian Agrion. 



1) Amer. Jn. of Sci.. 26. pp. 73-75, 1908. 



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