COLOR AND PATTERN IN ANIMALS 



411 



utter indistinguisliability of the larvae is something that needs 

 to be experienced to be fairly realizcHJ. 



Far more striking are those cases of protective resemblance 

 in which the animal re- 

 sembles in color and sha])e, 

 sometimes in extraordi- 

 nary detail, some partic- 

 ular ol)jcct or i)art of its 

 usual environment. Cer- 

 tain parts of the Atlantic 

 Ocean are covered with 

 great patches of seaweed 

 called the Gulf weed {S(ir- 

 gassum), and many kinds 

 of animals — fishes and 

 other creatures — live upon 

 and among the algic. No 

 one can fail to note the 

 extraordinary color resem- 

 blances which exist be- 

 tween these animals and 

 the weed itself. The gulf 

 weed is of an olive-yellow 

 color, and the crabs and 

 shrimps, a certain flat- 

 worm, a certain mollusk, 

 and certain httle fishes, 

 all of which live among 

 the Sargassiirn, are exactly 

 of the same shade of yel- 

 low as the weed, and have 

 small white markings on 

 their bodies which are 

 characteristic also of the 

 Sargassum. The mouse- 

 fish and the little sea- 

 horses, often attached to 



the Gulf weed, show the same trails of coloration (Tig. 2.'/J). 

 The slender grass-green caterpillars of many moths and butter- 

 flies resemble very closely the thin grass blades among which 

 they Uve. The larvae of the geometrid moths, called inchwgniiii 



Fig. 253. — A ripomelrid Inn'a on ft oranoh. 

 (The larva !.•< tlic upper riRht-hnixI projection 

 from the twig.) 



