Sept., 1906.] Cook : Validity of Thanaos ausonius. 125 



23. Euhalesidota pura Neumcegen. 



24. Halesidota ambigua Strecker. 



25. Halesidota mixta Neumcegen. 



26. Halesidota significans H. Edwards. 



27. Pkryganidia californica Packard. 



28. Alypia maccullochii Kirby. 



ON THE SPECIFIC VALIDITY OF THANAOS 

 AUSONIUS LINTNER. 



By John H. Cook, 

 Albany, N. Y. 



Plate III. 



During the last four years I have been searching for Thanaos auso- 

 nius (Lintn.) on the pine barrens west of Albany, N. Y. The indi- 

 vidual which Lintner described under that name was taken in this local- 

 ity, and it seemed reasonable to expect it here if anywhere. Over five 

 hundred butterflies belonging to this genus were taken, of which two 

 hundred and eleven were T. martialis. No "ausonius" appeared to 

 reward my efforts. 



At Dr. Dyar's suggestion I made a comparative study of martialis 

 and icclus with a view to determining, if possible, whether or not 

 ausonius is entitled to specific distinction. This inquiry has been 

 diligently prosecuted, and the results are here given. 



A glance at the genitalia of ausonius* was sufficient to prove it 

 distinct from icclus and to show that if not a good species it must be 

 regarded as a sport of martialis. From this species it was separated 

 by Lintner on the grounds of its small size, and the absence of the 

 fenestrate spots on the primaries ; the other characters " distinguish- 

 ing " it being of comparatively little importance. 



Considering the genitalia of the greatest morphological value I first 

 compared the tip of the right clasp of " ausonius" with the figure 

 thereof given in Scudder's "Butterflies of the Eastern United States 

 and Canada." This figure I found to be measurably accurate though 

 somewhat diagrammatic. I next compared the tip of the left clasp of 

 " ausonius" with Scudder's figure of the left clasp of martialis, and 



* The type in the Lintner memorial collection was studied in detail by the writer. 



