COLOR AND PArrERX IX ANIMALS 



4()9 



Fio, 250. — Chrj-salid of swallowtail 

 butterfly, Papi7«o, which cIo(*<'Iy re- 

 sembles the bark on which it rej*!.-*. 



resemble in color and general external appearance the surface 



of the object on which they rest. The chrysalids of various 



Papilios are indeed marveloiisly 



faithful imitations of bits of 



rough bark (Fig. 250).- 



The larvffi (caterpillars) of 



various moths, particularly Geo- 



metrid and Sphingid species, 



often appear in two color types, 



one brown and the other green. 



Poulton has shown by experi- 

 ment and observation with some 



of these species that those larva) 



reared among green leaves and 



twigs become green, while those 



on dry branches become brown. 



This variable protective reseml)lance, like that of Trimrro- 



tropis, Galgulus, and the Papilio chrysalids, also is fixed aftc i- 



being once acquired. 



An interesting exam])le of 

 color harmony which may bo 

 classified under the head of 

 variable protective resem- 

 blance is that of the larva? of 

 Lycoena sp., abundant on the 

 flower heads of the California 

 buckeye, ^€sculiis cahforniciis, 

 that blooms in May. Tlie butis 

 of the buckeye are green, or 

 gi'een and rose, or even all 

 rose externally. Tlie (juiet 

 sluglike Lycirnid hirvu' lie 

 longitudinally along the buds 

 and their short stems, and 

 are either green with faint 

 rose tinge, esj^ecially along 

 the middle of the back, or 

 are distinctly rosy all over, 

 depending strictly uj)<»n tlu^ 



color tone of the particular branch serving as their habitat. 



The correspondence in shade of color is strikingly exact: the 



Fig. 2r)l. — Two ortliopterous leaf hoppers 

 or membraoids: 'llie iipi)er one. Xtro- 

 phyllum simile: the lower one, Clndo- 

 notus humbcrtimus. (.\fter BoHvar.) 



