NVMIMIALIXAK: rilK (JKMS I'OLVCiOXIA. 313 



ri(l<re iicarlj' moctiuy- that of tlie supralatenil tiil)orcle above it and at its upper extrem- 

 ity slightly elevated : siipernunierary Aviiig tubercle ])retty strongly coini)ressed with 

 a rather sharp ridge, its liighest point bluntly rounded and rather more prominent than 

 the basal tubercle, falling ofl" rapidly Ijelund. Wings also consideral)ly protuberant 

 near the posterior border in tlie middle of the upper lialf and elevated into a blunt 

 conical tubercle. Metanotum with a pair of small, conical, supralateral, central warts ; 

 joints of the legs and antennae thickened a little centrally at the incisure. Abdomen 

 separated from the thorax by a very deep incision; its dorsum very much arched longi- 

 tudinally, provi(U;d witli a dorsal series of low, small, conical warts on the anterior 

 edges of tiic second to eighth segments; a series of more or less elevated, conical, 

 usually pointed, slightly forward and outward directed, laterodorsal tubercles on the 

 centre of the second to seventh segments, largest on tiie fourth; the eighth also some- 

 times with a scarcely elcAated rounded wart at the same point, and the first segment 

 with a sliglit conical wart similarly placed but on the anterior edge of the segment ; 

 a series of small, bluntly rounded, suprastigmatal warts, placed a little in advance of 

 tlie middle of the second to seventh segments. Preanal button formed of a pair of stout, 

 rounded but well raised, coarsely punctured, longitudinal, subdorsal ridges, slightly 

 curved, almost equally approximate at either end, each terminating in a blunt short tuber- 

 cle. Cremaster viewed from above verj^ long and slender, tapering a little, twice as 

 long as its medium breadth, rather broadly and deeply channeled as far as the terminal 

 ridge; viewed laterally it is equal, a little enlarged at the very tip, slightly curved; the 

 apical field of hool^lets nearly circular, a little produced at the anterior outer surface. 

 Anal booklets not very long, moderately slender, the basal half straight and equal, the 

 apical half enlarging somewhat but not greatly, curved into something like a semicircle, 

 the apex l)ent a little more and directed toward the base, the tip bluntly pointed. 



The butterflies of this genus are spread over nearly the whole north tem- 

 perate zone, but their metropolis is unquestionably North America.* 

 Only three species distinct from American forms are known to occur in the 

 Old AVorld and these are all representatives of North American species ; 

 one of them is confined to southern Europe and western Asia ; a second 

 occurs further south in China ; while the third extends from ocean to ocean. 

 One more species, which has been identified with our progne, but which 

 will more likely [)rove to be its representative zephyrus Edw., has been 

 found in the extreme north east of Siberia. In North America, on the 

 other hand, we find no less than six species east of the Rocky Mountains, 

 while on the western coast and in the Rocky jNIountain region itself, where 

 some of these also are found, several other reputed species occur, and per- 

 haps others aw^ait recognition ; still two other species are recorded from 

 Mexico. Two of the species of this genus are much larger than the others 

 and occupy more southern stations, one in China, the other in the United 

 States, especially in the South. The American species occurring east of 

 the Rocky INIountains are all, with possibly one exception, found within the 

 limits of New England ; one of them, the largest, has the most extensive 

 range in the settled parts of the coimtry, being common not only to the 

 southern states of the Union but also to the Alleghanian fauna and occur- 

 ring occasionally in the Canada district ; a second is characteristic of the 



* It is evidently by an oversight that Kirby America of her share of the genus, for at a 

 (Jouru. Koyal Duhl. soc. v: 170,) deprives previous page he speaks of one of our species. 



40 



