224 



PSYCHE. 



[June 189S. 



it is the mature color thrust back into 

 the juvenile stage, to the obliteration of 

 any trace of the saddle which once may 

 have prevailed there ; and is in keeping 

 with the present almost complete 

 assumption of the mature characters at 

 the second larval stage. In support of 

 this position I would point out that 

 traces of the saddle still exist in the 

 mature forms of other filamentous cat- 

 erpillars of Papilionini allied to Laer- 

 tias, — Ornithoptera, Menelaides, etc., 

 indicating a still larger development of 

 the same in the earlier stages of the 

 types with which, unfortunately, we 

 are not yet acquainted. In Laertias, 

 then, the saddle has been crowded 

 back out of existence. 



Another line of nearly as high devel- 

 opment we find in Iphiclides, where 

 the extraordinary bristles and tubercles 

 are lost with the very first stage and 

 maturity marks the second. Here 

 again no saddle appears, the only trace 

 of it left being in the slight deepening 

 of the color in the new-born caterpillar 

 near the extremities of the body ; here 

 I conceive that tlie phyletic stage 

 marked by the saddle and formerly 

 developed in later stages from the in- 

 cipient contrasts of the first, has been 

 pushed back without invading the first 

 until it is entirely skipped. 



A third line is represented by the 

 remaining genera in which the saddle 

 is definitely formed and becomes a 

 marked feature of the earliest stages, to 

 be lost only at a comparatively late 

 period of life, — in one instance, Hera- 

 clides, not at all. Its loss, however, is 

 effected in two very different methods. 



as already pointed out, in Papilio and 

 in the other genera, indicating lines 

 along which future strikingl}' different 

 processes may go on with widely differ- 

 ent results ; — in curious contrast to the 

 somewhat similar results following 

 quite different lines which we see in 

 Iphiclides and Papilio. In Eupho- 

 eades and Jasoniades we see also the 

 development of special and complicated 

 markings from the simple spots which 

 have replaced the tubercles ; traces of 

 the same may be seen in Heraclides. 



This review has but imperfectly 

 shown what curious and striking dis- 

 tinctions in form and coloring are pos- 

 sible, distinctions which indicate within 

 the histor}' of single lives the immense 

 phyletic changes that have occurred 

 within the group. These changes are 

 far greater both in structure and in 

 design than can be proved to have 

 occurred in other phyletic types among 

 butterflies, to which have been univer- 

 sally accorded by the most conservative 

 of systematists the rank of genera. 

 Shall we refuse to recognize and so- 

 consign to oblivion the more interesting, 

 more important and more obvious dif- 

 ferences which here obtain by classing 

 all the forms under one, wide-reaching 

 generic name.'' It were a veritable 

 travesty of Nature. 



Explanation of Plate 5. 



Fig. I. Laertias philenor. 



2. Ipliiclides ajax. 



3. Jasoniades glaucus (After Gruber). 



4. Euphoeades troilus. 



5. Heraclides cresphontes. 



6. Papilio astyanax. 



