764 AN INTRODUCTION TO ENTOMOLOGY 



The larva feeds on Car ex. The species is either single-brooded or 

 requires two years for the development of a brood. 



A closely allied species, CEneis katahdin, is found on Mount 

 Katahdin, A'laine. This is called the Katahdin butterfly. 



Subfamily HELICONIIN^ 

 The Heliconians 



This subfamily consists chiefly of tropical butterflies. They are 

 of medium or rather large size, and are easily recognized by their 

 narrow and elongated fore wings, which are usually more than twice 

 as long as broad. Most of the species are striking in appearance, 

 being black banded with yellow or crimson, and sometimes with blue. 

 The discal cell of the hind wings is closed by a well-preserved vein. 

 The following species is the only one found in our fauna that un- 

 questionably belongs to this subfamily. 



The zebra, Heliconius charitdnius. — This is a black butterfly with 

 its wings banded with lemon yellow. There are three bands on the 

 fore wings ; on the hind wings there is a broad band parallel with the 

 front wings when they are spread, a submarginal row of about fifteen 

 spots, and a row of dots on the outer margin near the anal angle. 

 The wings expand from 62 mm. to 100 mm. The larva feeds upon 

 the passion-flower. This species is found in the hotter portions of 

 the Gulf States. 



There are two other species found in the United States that are 

 placed in this subfamily by some writers; but in each of these the 

 discal cell of the hind wings is open as in the Nymphalina^. These are 

 the following. 



The Julia butterfly, ColcBnis julia. — This butterfly resembles the 

 true heliconians in having very long and narrow fore wings, these 

 being more than twice as long as broad. The upper side of the wings 

 is dark reddish orange, with the margins of the wings black, 

 and with a more or less distinct black band cutting off the outer 

 third of the fore wings. On the lower surface the wings are pale rusty- 

 red, mottled with a darker shade. The wings expand about 85 mm. 

 This is a very common species in the tropics of America and is found 

 in the extreme southern part of the United States. 



The gulf fritillary, Dione vanlllco. — In this species the front wings 

 are about twice as long as broad, but the markings of the wings re- 

 semble those of a fritillary more than those of an heliconian. The 

 wings are reddish fulvous above; the veins of the front wings are 

 black on the outer two-thirds of the wing; the black expands into 

 spots at the ends of veins M3 to anal ; there are two white spots in 

 the discal cell and one at the apex of it, each of these spots is sur- 

 rounded with black; cells M3, Cu], and Cu2 each contains a round 

 black spot. The outer margin of the hind wings has a broad 

 black border, which contains a fulvous spot in each cell. The wings 

 expand from 55 mm. to 75 mm. 



The larva feeds on the passion-flower. In addition to the six 

 rows of thorny spines, which characterize the caterpillars of many 



