276 Colour and the Struggle for Life 



his classical paper. Such an arrangement is inconvenient, and I have 

 followed Wallace in keeping the two categories distinct. 



The visible colours of animals are far more commonly adapted for 

 Protective Resemblance than for any other purpose. The concealment 

 of animals by their colours, shapes and attitudes, must have been well 

 known from the period at which human beings first began to take an 

 intelligent interest in Nature. An interesting early record is that of 

 Samuel Felton, who (Dec. 2, 1763) figured and gave some account 

 of an Acridian (PhyUotettix) from Jamaica. Of this insect he says 

 "the thorax is like a leaf that is raised perpendicularly from the 

 body 1 ." 



Both Protective and Aggressive Resemblances were appreciated 

 and clearly explained by Erasmus Darwin in 1794 : "The colours of 

 many animals seem adapted to their purposes of concealing them- 

 selves either to avoid danger, or to spring upon their prey 2 ." 



Protective Resemblance of a very marked and beautiful kind is 

 found in certain plants, inhabitants of desert areas. Examples ob- 

 served by Burchell almost exactly a hundred years ago have already 

 been mentioned on p. 2/3. In addition to the resemblance to stones 

 Burchell observed, although he did not publish the fact, a South 

 African plant concealed by its likeness to the dung of birds 3 . The 

 observation is recorded in one of the manuscript journals kept by the 

 great explorer during his journey. I owe the opportunity of studying 

 it to the kindness of Mr Francis A. Burchell of the Rhodes University 

 College, Grahamstown. The following account is given under the 

 date July 5, 1812, when Burchell was at the Makkwurin River, about 

 half-way between the Kuruman River and Litakun the old capital of 

 the Bachapins (Bechuanas) : " I found a curious little Crassula (not 

 in flower) so snow white, that I should never has [have] distinguished 



it from the white limestones It was an inch high and a little 



branchy, and was at first mistaken for the dung of birds of the 



passerine order. 1 have often had occasion to remark that in stony 

 place[sj there grow many small succulent plants and abound insects 

 (chiefly Grylli) which have exactly the same color as the ground and 

 must for ever escape observation unless a person sit on the ground 

 and observe very attentively." 



1 Phil. Trans. Ray. Hoc. Vol. LIV. Tab. vi. p. 55. 



- Zoonomia, Vol. i. p. 509, London, 1794. 



3 Sir William Thiseltou-Dyer has suggested the same method of concealment (Annuls oj 

 Botany, Vol. xx. p. 123). Referring to Aiiacampseros pupynicea, figured on plate ix., the 

 author says of its adaptive resemblance: "At the risk of suggesting one perhaps somewhat 

 far-fetched, I must confess that the aspect of the plant always calls to my mind the 

 dejecta of some bird, and the more so owing to the whitening of the branches towards the 

 tips" (loc. cit. p. 1'26). The student of insects, who is so familiar with this very form of 

 protective resemblance in larvav, and even perfect insects, will not be inclined to 

 consider the suggestion far-fetched. 



