HESPERIOIDEA OF AMERICA 51 



9. Dark marks conspicuous, secondaries checkered; fresh specimens with 



a purplish lustre martialis 



Not such insects 10 



10. Larger, marks more or less obscured toward base of primaries. . . . 



persius, pernigra 



Usually smaller, marks more evenly distinct over entire wing 11 



11. Fringes usually evenly colored 12 



Fringes pale tipped; western form persius, race afranius 



12. Secondaries with pale spots below clear cut lucilius 



Spots absent or diffuse; western species eallidus 



13. Tufts of dark scales in base of white fringe all along outer margin 



scudderi, pacuvvus 



Earely with a suggestion of such tufts 14 



14. Primaries narrower than normal; $ with tibial tuft funeralis 



Primaries normal, no tuft tristis, clitus 



Under surface of secondaries with some white inside of fringe. .. . 

 tristis, var. tatms 



1. THANAOS ICELUS 



Nisoniades icelus Scudder & Burgess, Proc. Bost. Soc. Nat. Hist, xiii, 288, 



1870. 

 Lintner, 23rd Ann. Rep. N. Y. St. Cab. Hist. 162, pi. 7, ff. 5, 6, 1872. 

 Scudder, Butt. New Eng. n, 1507, 1889. 

 Holland, Butterfly Book 333, pi. xlviii, 17, 1898. 



Arizona, Colorado, Massachusetts, Pennsylvania and southern Canada; 

 May to July. Athabaska and Mackenzie, June (Cary). North Carolina, 

 April (Brimley & Sherman). 



2. THANAOS BRIZO 



Tlvanaos brizo, Boisd. & Lee, Lep. Am. Sept. pi. 66, 1833. 

 Scudder, Butt. New Eng., n, 1500, 1889. 

 Holland, Butterfly Book 332, pi. xlv, f. 7, 1898. 



Atlantic coast to Rocky Mountains, Gulf to Southern Canada; April to 

 July. Eastern specimens of this species are easy to identify, but it is 

 difficult to separate burgessi, lacustra and brizo when all are from the 

 same locality. 



2a. race SOMNUS 

 Nisoniades somnus Lintner, Papilio i, 73, 1881. 



Florida, February and April. This is merely a very dark form of brizo. 



3. THANAOS BURGESSI 



Thanaos burgessi Skinner, Trans. Am. Ent. Soc. XL, 203, 1914. 

 Arizona and New Mexico; March, April and August. 



4. THANAOS LACUSTRA 



Nisoniades lacustra Wright, Butt. W. Coast 253, pi. xxxn, 480, 1905. 



California, June. This is not a form of brizo, as has been stated, but is 



