386 
THE STUDY OF INSECTS. 
The Orange Sulphur, Eurymus curytheme (E. eu- 
ryth'e-me).—This species closely resembles philodice in¬ 
size, shape, and markings. The typical form differs from 
philodice in being of an orange color above instead of a 
yellow. 
The Orange Sulphur is a Western species, occurring in 
the Mississippi Valley and west to the Pacific Ocean. It is 
one of the most polymorphic of all butterflies ; the forms 
differ so much in appearance that four or five of them have 
been described as distinct species. The larva feeds on 
clover. 
The DogVhead, Zerene ccesonia (Ze-re'ne cae-so'ni-a.)— 
The wings are lemon-yellow above, bordered on the outer 
margin with black. On the hind wings the border is nar 
row, but on the fore wings it is broad. The outline of the 
yellow of the fore wings suggests a head of a dog or of a 
duck, a prominent black spot on the discal vein serving as 
the eye. This is an abundant species in the Southeastern 
and Southwestern States, extending from the Atlantic to 
the Pacific. The larva feeds on clover. 
The Black-bordered Yellow, Xanthidia nicippe (Xan- 
thid'i-a ni-cip'pe).—The wings above are bright orange, 
marked with blackish brown as follows : on the fore wings a 
narrow bar at the apex of the discal cell, the apical portion 
of the wings, and the outer margin ; on the hind wings, the 
outer margin. In the female the outer marginal band is in¬ 
terrupted at the anal angle of each wing, and on the hind 
wings it may be reduced to an apical patch. The expanse 
of wings is from one and six tenths inches to one and nine 
tenths inches. 
The species occurs from Southern New England to 
Florida and west to Lower California. The larva feeds on 
several species of Cassia. 
The Little Sulphur, Enrema lisa (Eu-re'ma li'sa).— 
Although this species is larger than the following one it 
is considerably below the average size of our yellows, the 
