l 5& The Ottawa Naturalist. | November 



the Emperor moth, nay even the Polypectron, the gorgeous 

 Malacca pheasant, the ocellated turkey with a row of eye- like 

 spots at the end of the tail, may thus find explanation. Many of 

 :the small shore fishes, like the Gobies, and the Skulpin {Callwny- 

 jnus), exhibit in the dorsal fin one or more shining eye-like spots, 

 softer) explained as due to sex-selection, as the males usually bear 

 these ornaments ; but they may be of a warning character. 



Trophic Coloration. Food is frequently potent in color pro- 

 duction. Translucent young fishes may have a bright pink color 

 over the abdominal area, due to Copepods, &c, undergoing di- 

 gestion, while Salpae often owe their yellow color to diatoms 

 swallowed as food. N. Chautard found that green chlorophyll re- 

 mained unchanged in color when taken in by animals. Examples 

 are green oysters among Mollusks. and the green Cantharides 

 among insects. Medical men are familiar with the effect of digest- 

 ing colored materials. Young children may be brilliantly tinted 

 over the head, face, arms and skin after accidentally swallowing 

 aniline dyes, and bird-fanciers, who give young canaries Cayenne 

 pepper in their food, can deepen the yellow plumage, as the fatty 

 Triolin of the pepper (not the Capsicin as often stated) passes to 

 the feathers. Sauermann's experiments with white hens showed 

 that the Triolin colored the breast feathers most markedly, but 

 the head remained perfectly white. Red, in plumage, is often a 

 very fleeting color, and Moseley found a South African stork 

 whose brilliant rose-color was all washed out by a heavy shower 

 of rain ! The seasonal red-color of the crossbill, the brown linnet 

 and red pole disappears, changing to a greenish yellow in the bird 

 first-named, while the carmine breast and forehead of the latter fades 

 away altogether, like the dark blueof the Indigo bird's feathers, which 

 assume a dingy brown color for the winter. Trophic colors, or 

 tints due to food have been as yetlittle studied although the Cochi- 

 neal insect is of great commercial value, owing to the red color of 

 the food s'ored up in the body of the wingless female, of which 

 70,000 dried specimens, I am informed, go to make 1 lb weight ot 

 the dye material. The caterpillar of Bryophila is yellow when it 

 feeds on Lichen juriiperinus\ but grey when subsisting on the grey 

 Lichen saxatilis. Such instances undoubtedly exemplify trophic co- 

 lorr.tion. Allied to trophic coloration and yet distinct from it, is 



