774 



REPORT UNITED STATES GEOLOGICAL SURVEY. 



tbe hind wings have two short, thread-like tails, the inner one the longest, and tipped 

 with white ; along the hind margin of these same wings is a row of little pale-blue 

 spots, interrupted by a large orange-red crescent inclosing a small black spot ; the 

 wings beneath are slate-gray, with two wavj' streaks of brown edged on one side with 

 white, and on the hind wings an orange-colored spot near the hind angle, and a larger 

 spot of the same color inclosing a black dot just before the tails. It expands one inch 

 and one-tenth. (Harris.) It ranges, according to Scudder, from the Atlantic to the 

 Pacific, and from the Canadian border to the Gulf of Mexico and southward to Ven- 

 ezuela. Besides the hop, it feeds on Cratwgus aj)iifolia, Hiipericum auream, and Phaseolus. 

 The Semicolon Butterfly, Pylygonia {Grapta) interrogation is (Fabr.). — A brown 

 caterpillar with a red head and pale-yellow or brownish spines, sometimes defoliating 

 the vine, and changing into a large tawny-orange butterfly with jagged and angular 

 wings. 



Though tlie caterpillars of this common butterfly lives on the Ameri- 

 can elm and lime trees, it is also at times quite destructive to the hop- 

 vine, sometimes abounding " to such a degree as totally to destroy the 

 produce of the plant." — (Harris.) The caterpillars are so conspicuous 

 early in August that they can be easily plucked otf with the hand. The 

 chrysalides, which late in August suspend themselves beneath the leaves 

 and to the stems of the vine, can be picked off, though Harris recom- 

 mends that the vine " should be cut down, stipped of the fruit that is 

 suf&ciently ripened, and then burned." 



Caterpillar. — " Browish, variegated with pale yellow, or pale yellow variegated with 

 brown, with a yellowish line on each side of the body ; the head is rust-red, with two 

 blackish branched-spines on the top ; and the apines of the body are pale yellow or 

 brownish, and tipped with black." — (Harris.) 



Chrysalis. — "Ashen browu, with the head deeply notched, and surmounted by two 

 conical ears, a long and thin nose-like promin'^nce on the thorax, and eight silvery spots 

 on the back. The chrysalis state usually lasts from eleven to fourteen days ; but the 

 later broods are more tady in their transformations, the butterfly sometimes not ap- 

 pearing in less than twenty-six days after the change to the chrysalis." — (Harris.) 



Butterfly. — Tawny orauge, wings very angular, though less dentate than in Pohjyoixia 

 comma andprofine, but the " tails " of the hind wings are longer and more pointed. The 

 fore wings are tawny orange, but dark brown along the outer margin, with the extreme 

 edge washed with violet. Beneath ash-colored like old unpaiuted pine wood, with a 

 large heavy silver mark of interrogation. It is much larger than F. comma snidprogne, 

 expanding over two and a half (2.G0) inches. 



Harris states that " great numbers of the chrysalides are annually 

 destroyed by little maggots within them, which, in due time, are trans- 

 formed to tiny four-winged flies, (Pteromalus vanesscc,) which make their 

 escape by eating little holes through the sides of the chrysalis." 



The Comma Bvttbrfly, PoJygonia {Grapta) comma {Harris). — This 



is a smaller butterfly than the pre- 

 ceding, appearing in May and lay- 

 ing its eggs on the leaves of the 

 hop-vine, as well as other plants 

 (the elm, nettle and Baehmeria cylin- 

 drica). The caterpillars change to 

 chrysalides in the middle of July, 

 their butterflies lay eggs for a new 

 brood of caterpillars, which change 

 to chrysalides the first of Septem- 

 ber and the butterflies hibernate. 



Fig. 44. — Progne Butterfly. 

 Description. — The cater])iliar closely resembles that of G. interrogationis. The but 

 tcifly is much smaller than P. interrogationis, and the fore wings of much the same shape, 

 but Ibo hind wings arc more toothed, with a broad, less sharp " tail." The spots and 

 color are much the same but darker. Hind wings with an angular, slender, silvery 

 mark, somewhat like a comma. The inner half of both wings darker wood-ash color 

 than in P. interrogationis. Expanse of wiugs, 2J inches. It is very closely allied to P. 

 progne (Fig. 44). 



