PAPILIONINAE : THE GENUS LAERTIAS. 1233 



paneled, to nearly double the ■width of the metathorax, the superior edges of the wings 

 partaking of the dilatation, the outline of the whole being strongly and regularly 

 curved, and the lateral ridge thus formed very sharp and greatly depressed; trans- 

 versely these segments are broadly rounded. On either side of the fourth to seventh 

 abdominal segments is a laterodorsal series of greatly compressed, elevated, lami- 

 nate riilges, the edges of which are regularly rounded longitudinally and rugulose ; in 

 continuation of these are slight carinae, converging to the superior sides of the cre- 

 master; between them the surface is nearly flat, and below them the sides of the 

 abdomen are scarcely rounded, steeply sloped; in posterior continuation of the lateral 

 expansion of the anterior part of the abdomen is a substigmatal carina, indistinct and 

 rounded on the fifth and sixth segments, extending to the inferior sides of the cre- 

 master; beneath, the abdomen is broadly rcmuded transversely. . Preanal button 

 bounded by very broad, low walls, increasing in breadtli and diverging anteriorly, 

 then suddenly bending at right angles toward each other, meeting and emitting from 

 the posterior border, at equal distances from the sides, a pair of small, depi-essed, 

 recumbent, rounded, lobe-like tubercles, directed backward. Cremaster short and 

 broad, tapering strongly, much broader below than above, the sides strongly hol- 

 lowed, the upper portion equal until near the tip, carinate at the sides, broadly docked 

 at tip, the apical field of anal booklets nearly circular, but docked a little beneath. 

 Hooklets short, the stem a little curved, quite stout, increasing in size a little toward 

 the apical expanded portion, which is suddenly enlarged to fully twice its breadth, 

 curved strongly over and downwards, the sides produced in front and bluntly pointed, 

 leaving the apical border emarginate. 



This group of swallow-tails is peculiar to the southern portion of North 

 America and is apparently composed of only two or three species, some 

 belonging to the south and almost confined to the Antilles ; the last (here 

 described) belonging to the north and far more widely sj^read. 



This group stands apart from the other New England genera of Pa- 

 pilioninae and approaches more nearly in structure the gigantic Orni- 

 thopterae of the East Indies ; but it is still more closely allied to the 

 tailless genus Ithobalus, belonging to tropical America, the transforma- 

 tions of two or three of whose species are known through Burmeister. 



The butterflies are among the smaller of the swallow-tails, but still 

 large and magnificent, of an intense black, shading off into brilliant me- 

 tallic tints of green and steel as the light strikes across the wings ; the 

 outer border has a submarginal series of large, pale greenish spots and the 

 upper median nervide bears a subspatulate tail ; beneath, the fore wings 

 are duller, the pale spots repeated, but the outer half of the hind wings is 

 even more brilliant and variegated than above, the spots being much 

 larger and changing to deep orange, and the wings more or less spotted 

 with white. "These gorgeous swallow-tails," says Gosse, "seem to be 

 of royal blood, to have a presence that distinguishes them from the meaner 

 herd" (Lett. Alab., 78). 



The genus is peculiar among our swallow-tails for the length of the 

 middle tarsi and the slight inequality in the length of the antennae in the 

 two sexes, those of the male being relatively the longer. The males have 

 a reflected inner margin to their hind wings as far as the internal ucrv- 

 ure, which is enveloped in the fold which conceals androconia. One spe- 



