PAPILIONINAE ; IPHICLIDES AJAX. 1273 



Food plants. The caterpillar, according to numerous authorities, feeds 

 upon the papaw, Asiinina triloba Dunal, and, according to Dr. Chapman, 

 upon all our other species of the same genus, A. parviflora Dunal, 

 A. grandiflora Dunal and A. pygninca Dunal. I?oisduval and Le Conte 

 also state that it feeds upon the latter and upon Anona palustris (whatever 

 that may be) — plants belonging to the Anonaceae or custard-apple family. 

 No one appears to have found it on any other plant excepting Aaron, 

 who states that it is found also on "spice wood," by which he doubtless 

 means Benzoin odoriferum, and on "upland huckleberry," someone of the 

 Vaccinieae, plants belonging respectively to the Lauraceae and Ericaceae, 

 and far removed, structurally, from the Anonaceae. But several persons 

 have observed that papaws were not to be foxuid in some northern localities 

 where the buttei-fly had been found, such as Ames, la. and Racine, Wis. 



Habits of the caterpillar. The 3'oimg caterpillar as soon as hatched 

 devours its egg-shell, but usually leaves the part glued to the leaf. The cat- 

 erpillars live, according to Wittfeld, on the under side of leaves, and, more 

 than other species of his acquaintance, shows cannabalistic propensities. 

 Some of the caterpillars, as shown by Mr. Edwards's observations, attain 

 theirfull growth in twelve days, although others, especially the produce of the 

 earliest butterflies, require nearly a month. They do not draw the leaves 

 of the plant together like some other larvae of Papilioninae, but are to be 

 found in eveiy stage "resting on the surfaces of the leaves, and one would 

 suppose they must be nearly exterminated by birds. But like all Papilio 

 larvae they emit from the head [first thoracic segment] , at the same time 

 that they project a Y-shaped tentacle, a peculiarly acrid and sickening 

 odor, which must effectually protect them" (Edwards). In a letter, Mr. 

 Edwards adds that he does "not believe a starving bird would touch one, 

 the stench being so strong as nearly to turn one's stomach," yet I could 

 not induce one in the second stage to eject its osmateria. 



Folymorphisin and life history. Science is deeply indebted to Mr. 

 "W. H. Edwards, for the thorough manner in which he has worked out the 

 history of this butterfly by careful studies in the field and innumerable ex- 

 periments. This author has not only indisputal)ly established the identity 

 of two forms previously described as distinct species (though often pre- 

 sumed to be identical), but has proved the existence of a third permanent 

 form and has admirably traced the relations of each foi-m to the others. 

 The account given below is almost entirely based on his observations. 



No histories of butterflies are of deeper interest than those of polymor- 

 phic species, whether considered in thcmseh^es alone or in the light they 

 are destined to throw upon the origin of species and races, problems which 

 demand the profoundest thought and most conscientious investigation ; and 

 since this species is polymorphic in a larger sense than almost any other 

 American buttei-fly is known to be, our interest is greatly enhanced. 



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