COLORATION AND MIMICRY 295 



markings to imitate surroundings, although in less degree 

 than do the flat fishes. 



There is, however, a rather striking exception to this in 

 some of the rock fishes, for while the young of some are 

 green among Zostera, brown or red among Fucus, etc., 

 the beautiful " Blue-striped Wrasse " or " Cuckoo Wrasse " 

 (Labrus mixtus) is very conspicuous at all times, but 

 especially during the breeding season, when the colours of 

 the male are as follows : 



A groundwork of deep orange, nearly red on the back, 

 and a delicate lemon-yellow underneath. Along the sides 

 from head to tail there are, generally, fine lines of bright 

 blue, varying from deep ultramarine to a delicate " sky- 

 blue." The head is sometimes marbled with blue, purple, 

 and pink, sometimes uniformly deep blue ; the dorsal, 

 pelvic, and ventral fins edged with blue. 



The female, which has been described as a separate 

 species, under the name of the " Three-spotted Wrasse " 

 (Labrus trimaculatus), is of the same ground colour as the 

 male, but instead of the blue markings it has three large 

 spots of black on the back, near the tail. 



This fish, which is just under a foot in length, is gorgeous 

 in the extreme ; no coloured figure that I have seen of it 

 conveys a fair idea of its beauty. 



In the winter the male loses nearly all the blue, and 

 shows a faint trace of three black spots on the back, while 

 the female loses the greater part of the black in the spots, 

 and shows a faint trace of the male's blue lines. 



(Although it has always been described as two species 

 Dr Giinther expresses a suspicion that it is male and female 

 of the one kind. I have watched captive specimens through 

 the seasons, and they certainly are one.) 



Now this conspicuous fish is unarmed, and is good to eat ; 

 fishermen use it, with other wrasses, as bait for conger, etc. 



That the colours are due to sexual selection seems very 



