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, 
i.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 XLVIII, Fig. 1, $ ; 
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. —U n k n ow n. 
All the specimens I have seen come from Arizona, where the 
thing is apparently common. 
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