Genus Thanaos 



Butterfly. This species may be distinguished from T. pacu- 

 vius, a near ally, by the more mottled surface of the secondaries, 

 which in pacuvius are almost solidly black ; and from T. martialis, 

 another close ally, by the absence of the purplish-gray cast pecu- 

 liar to both sides of the wings of the latter species, and the less 

 regular arrangement of the bands of spots on the upper side of 

 the fore wings. The plate does not show these delicate but con- 

 stant marks of difference as well as might be desired. Expanse, 

 1.20-1.40 inch. 



Early Stages. Dr. Scudder has fully described these. The 

 caterpillar feeds on the columbine (Aquilegia canadensis). 



Lucilius ranges from New England to Georgia, is common in 

 western Pennsylvania and West Virginia, and extends westward 

 at least as far as the Rocky Mountains. 



(5) Thanaos persius, Scudder, Plate XLVI1I, Fig. i, $ ; 

 Plate VI, Fig. 34, chrysalis (Persius' Dusky-wing). 



Butterfly. This is a very variable species, some specimens 

 being light and others dark in color. There is scarcely any posi- 

 tive clue to the specific identity of the insect except that which is 

 derived from the study of the genital armature of the male, which 

 is a microscopic research capable of being performed only by an 

 expert in such matters. The student may be pardoned if, in at- 

 tempting to classify the species of this genus, and the present 

 species in particular, he should grow weary, and quote a few bib- 

 lical expressions relating to Beelzebub, the "god of flies." Ex- 

 panse, 1.20-1.45 inch. 



Early Stages. The caterpillar feeds on willows. Scudder has 

 with patient care described its life-history. 



The insect ranges from New England southward, and inland 

 across the continent to the Pacific. 



(6) Thanaos afranius, Lintner, Plate XLV, Fig. 5, $ (Afra- 

 nius' Dusky-wing). 



Butterfly. Closely related to the preceding species. The hind 

 wings on the upper side in the male 'sex are almost solid black, 

 the fringes paler. On the under side there is a double row of light 

 spots along the margin of the hind wing in both sexes. The 

 female is generally paler in color on the upper side than the male. 



Early Stages. Unknown. 



All the specimens I have seen come from Arizona, where the 

 thing is apparently common. 



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