1873.] COLOURING IN INSECTS. 157 



colour in correspondence with the prevailing tint of its district, 

 being light when from chalk, dark from peat, and reddish brown 

 from clay. Similarly, Dr. Moller, in the paper before referred to, 

 has recorded that Elaphrus riparius is of a brown colour when 

 in sandy districts, but is green when in meadow-lands. The 

 African Eremiaphila, described by M. Lefebvre*, furnishes an 

 excellent example of the class now under consideration. This 

 desert-insect is described as having perfect identity of colour 

 with the ground on which it lives, and is stated to vary in colour 

 from brown to silvery white, according to the colour of the soil on 

 which it occurs. One remarkable case recorded by Dr. Wallace 

 belongs perhaps to the present class. Referring to Bombyx cynthia, 

 the author observes t: — "The earliest bred specimens were of a pre- 

 dominant olive-green ground-colour, whereas the later bred, and 

 especially those that escaped from pupse in September, not having 

 passed a winter in cocoon, were of a predominant yellow tint. . . . 

 Exceptions of course occur to this rule, but they are very few. It 

 is hardly necessary to observe that these tints closely resembled the 

 shades of the Ailanthus-leaflets, which assume a yellower tint as the 

 season advances and the leaflets grow older." 



Although insects furnish the largest number of cases of " variable 

 protective colouring," examples are not wanting in other classes of 

 the animal kingdom. Thus among Crustacea the Chameleon Shrimp 

 (Mysis chamceleon) has been so named from its power of changing 

 colour according to the locality which it inhabits, being grey on 

 sand, brown among seaweeds, and green when among Viva and 

 Zostera. It is well known that many species of fish, especially of 

 the family PleuronectidcB, are capable of changing colour in cor- 

 respondence with the colour of the bank on which they are resting 

 or the water which they inhabit J. It is stated by Mr. Andrew 

 Murray, also, that various birds are capable of undergoing a similar, 

 though more permanent, alteration in colour §. 



Definition of variable protective colouring. 



The class of cases of which I have just given examples I propose 

 to group together in a fifth class of the above-given classification, 

 which, with this addition, is thus made to embrace all the known 

 cases of protective resemblance. It will therefore become necessary 

 to find a definition, as precise as the materials will permit, of the 



* Ann. Soc. Ent. de France, iv. p. 455. 



t Trans. Ent. Soc. vol. v. p. 485. 



J See, for instance, Yarrell on the Flounder, Brit. Fishes, 2nd ed. p. 304 ; 

 also Mr. Andrew Murray's paper on the " Disguises of Nature," Edinburgh 

 New Philos. Journ., Jan. 1860; and Prof. Cope on "The Method of Creation 

 of Organic Forms," Proc. Amer. Philos. Soc. vol. xii. 1871, p. 260. My friend 

 the late Mr. J. K. Lord, of the Brighton Aquarium, confirmed this statement 

 with regard to the Pleuronectidce. 



§ Loc. cit. p. 1 1. The species cited are the Grouse and Partridge : the former 

 are stated to be very light brown in the low corn districts, so as to match the 

 stubble ; while the Moor-Partridges, which frequent the heather, are said to be 

 darker than those of the lowlands. 



