448 THE ZOOLOGIST. 



at night. This is true of most ground-beetles, many Crickets, 

 Cockroaches, Ants, &c. Many of these insects hide away in the 

 daytime, so that no protective colours are then needed. But 

 many insects that are exposed both during the day and at night 

 have acquired green or yellowish colours that are protective at all 

 times, when living among foliage. Green-grasshoppers, Katydids, 

 &c, are examples." * 



Sometimes we find varied or almost contradictory suggestions, 

 as has been applied to the resemblance of Tree-Shrews to Squir- 

 rels. Lydekker considers this may have been originally due to 

 the extreme agility of the latter animals insuring them from pur- 

 suit by other creatures, as being a useless task. Hence it would 

 clearly be an advantage for a slower animal to be mistaken for a 

 Squirrel, f Wallace suggests that the resemblance is probably 

 due to the Squirrels being harmless creatures which cannot 

 alarm the insects around them by their movements, so that the 

 Insectivora which resemble them easily capture their food.t 

 Another protective quality possessed by Squirrels has been con- 

 jectured by Poulton as existing in its large bushy tail: "An 

 enemy in pursuit would be liable to get only a mouthful of fur." § 

 Ridley, in commenting on this proposed mimicry, is much more 

 cautious : " If this resemblance is to be reckoned an example of 

 mimicry, it is not easy to decide whether it is the Tupaia which 

 mimics the Squirrel, or the Squirrel the Tupaia. Possibly the 

 resemblance is accidental, both animals having taken on the most 

 inconspicuous colouring, and the most suitable form for their 

 environment." || Mr. Oldfield Thomas considers that the resem- 

 blance between the Bassaricyon, a Raccoon-like type of animal 

 (known at present only by a single skull from Costa Rica and a 

 skin from Ecuador)^ to the Kinkajou (Cercoleptes caudivolvulus) , a 

 well-known Raccoon inhabiting Central America and Northern 

 Brazil, is a case of true mimicry, although he is unable to 



* Abstract of a paper read before Morphol. Soc. ' Amer. Journ. Sci.' Feb. 

 1897 ('Ann. and Mag. Nat. Hist. Sixth Series, vol. xix. 354-6). 



f ' Eoyal Nat. Hist.' vol. i. p. 314. 



t ' Nat. Select, and Trop. Nature,' p. 76. 



§ ' Colours of Animals,' p. 209. 



|| ' Natural Science,' vol. vi. p. 28. 



IT Mr. Thomas informs me that the Brit. Mus. has very recently received 

 a second specimen. 



