52 IOWA STUDIES IN NATURAL HISTORY 



more nearly related to burgessi, though the genitalia differ enough to war- 

 rant regarding it as a distinct species. 



5. THANA08 GESTA 

 Thanaos gesta H.-S., Corr.-Blatt Eegensb. xvii, 142, 1863. 

 Thanaos invisus Butler & Druce, Cist. Ent. i, 114, 1872. 

 Biol. Cent.-Am., Ehop. ii, 455, pi. xci, ff. 7, 8, 9, 1899. 

 Nisoniades llano Dodge, Can. Ent. xxxv, 78, 1903. 

 Texas and Arizona; July. 



6. THANAOS PERSIUS 



Nisoniades persiAis Scudder, Proe. Ess. Inst, iii, 170, 1863. 

 Scudder, Butt. New Eng. ii, 1468, 1889. 

 Holland, Butterfly Book 334, pi. xlviii, f. 1, 1898. 



The typical form has an expanse of about thirty-five millimeters and is 

 dark and obscurely marked, especially on the basal half of the wings. It 

 occurs throughout the United States and north into Alaska; May to August. 



6a. race PEBNIGBA 

 Thanaos ■pernigra Grinnell, Ent. News xvi, 34, 1905. 

 California, July. A very dark Pacific Coast race. 



6b. race AFBANIUS 



Nisoniades afranius Lintner, 30th Eep. N. Y. Mus. Nat. Hist. 175, 1877. 



California, Utah, Colorado, Arizona; May, July and August. Afranius 

 does not exceed thirty millimeters and is rather distinctly marked and gray 

 powdered; the fringes are pale, sometimes almost white, at their tips. 



6c. race LUCILIUS 

 Nisoniades lucilius Scudder & Burgess, Proc. Bost. Soc. Nat. Hist, xiii, 



287, 1870. 

 Lint., 23rd Eep. N. Y. St. Cab. Nat. Hist. 164, pi. 7, ff. 1, 2, 1872. 

 Scudder, Butt. New Eng. ii, 1458, 1889. 

 Holland, Butterfly Book 333, pi. xlviii, f. 10, 1898. 



Northeastern United States and southeastern Canada, April and May. 

 Dr. W. T. M. Forbes has kindly identified slides of genitalia in my possession 

 as lucilius, which he regards as a species. I am unable to agree with this 

 and follow Skinner in placing it as a race of persius, though a careful 

 study of the early stages may show it to be distinct. It is usually smaller 

 than persius and more distinctly marked. 



7. THANAOS CALLIDUS 



Thanaos callidus Grinnell, Ent. News XV, 114, 1904. 

 McDunnough, Ent. News xxvili, 232, 1917. 



After an eventful and troublesome career' callidus has at last been run 

 down by Dr. McDunnough. It proves to be a good species, treated as 

 lilius Dyar by Skinner in his "Studies in the Genus Thanaos." The two 



