710 THE BUTTERFLIES OF NEW ENGLAND. 



Mr. Hope to be used as food by the natives of Australia, but Mr. Double- 

 day is inclined to doubt the truth of the statement ; even the most bar- 

 barous tribes would scarcely eat insects refused by birds ; and they are 

 too keen observers of nature to overlook the fact of such refusal. 



Tliese insects are polygoneutic and the winter is passed in the imago 

 state alone. The caterpillars of this and the immediately allied genera 

 feed wholly on Asclepiadaceae : in America Asclepias, Gonolobus and 

 Apocynum seem to be selected by them ; in Africa Calatropis is added to 

 the list. They live in almost complete exposure and do not seem even to 

 seek places of concealment when transforming. 



The egg is high, subfusiform, tapering but slightly on the basal half 

 and furnished with frequent longitudinal ribs. The larvae are provided 

 with a pair of very long, slender, fleshy papillae on the second thoracic 

 segment, and a similar but usually much shorter pair on the eighth abdom- 

 inal segment ;* the bodies are either greenish, transversely banded with 

 black and colored stripes or are nearly black, with transverse series of 

 pale dots. The chrysalids are green with a few golden spots on the 

 thorax, and the third abdominal segment is furnished with a transverse 

 series of raised, highly colored warts, beyond which the body tapers very 

 rapidly. 



EXCURSUS XXIII.— MIMICRY AND PROTECTIVE RESEM- 

 BLANCE; OR BUTTERFLIES IN DISGUISE. 



How she sucked, 

 Assimilated juices, took the tint, 

 Mimicked the form and texture of her food ! 



Browning.— i?ef? Cotton Night Cap Country. 



Yet nature is made better l)y no mean. 

 But nature makes that mean. 



Shakespeare.— TFw<e>-'s Tale. 



Every observer, even the most casual, has at some time had his atten- 

 tion arrested by the strange resemblance of some creature to the object 

 upon which it rested ; to this form of imitation the term mimicry was 

 applied as long ago as 1815 by Kirby and Spence in the introductory 

 letter to their treatise on entomology.! "You would declare," say they, 

 "upon beholding some insects, that they had robbed the trees of their 

 leaves to form for themselves artificial wings, so exactly do they resemble 

 them in their form, substance, and vascular structure ; some representing 

 green leaves, and others those that are dry and withered. Nay, some- 



*It will be seen, later, that the second ab- boring genera, which, in the mature caterpillar, 



doniinal segment may perhaps also be pro- are provided with well developed filaments on 



vided with a pair of minute filaments, at least this segment. 



in the earlier stages, a feature which would t Compare Distant, Rhoi\ Mai., p. 33, note, 



show the close affinity of Anosiatothe neigli- wliere a much later date is named. 



