106 Capt. G. E. II. Ban-ett-IIamlltoii on the 



its middle (in parnassice it joins it about its middle) ; fimbria 

 dull ijrey, quite dark. 



J/ah. Milwaukee, Wisconsin, July 24 {Dr. S. Grcnm'cher). 



Named after Mr. G. W. Peckliam, in recognition of liis 

 Avork on the habits of Wisconsin Ilymenoptera. 



East Las Vejras, New Mexico, U.S.A., 

 Dec. 13, 1001. 



XXI. — Investigations upon the Life-histort/ of Salmon, and 

 their Bearing on the Phenomena of Nuptial and Sexual 

 Ornamentation and Development in the Animal Kingdom 

 generally. By G. E. 11. Baurett-Hamilton, Capt. Sth 

 lioyal Irish Rifles. 



The coloration of animals, and especially that part of it 

 which seems to have a connexion with sex, presents us with 

 many problems of deep interest, and has formed the basis of 

 a number of speculations, some of them examples of the best 

 efforts of our strongest zoological thinkers. Many of these 

 theories are of great ingenuity and have marked roal stepping- 

 stones in the progress of our knowledge. For this reason it 

 would be in the highest degree ungrateful to attempt their 

 downfall. Nor, indeed, Avould such an assault prove likely 

 to be successful, so firmly established at the present day ai'e 

 the main lines of thought dealing with animal coloration. 



Yet field-naturalists must often have felt dissatisfaction at 

 the insufficiency of all known theories and have yearned for 

 the discovery of some law which, embracing all the pheno- 

 mena in its grasp, would place before their mind.s a compre- 

 hensive view of the whole question. At least that has been 

 my own experience. While perfectly ready to admit that if 

 some colours are p.rocryptic, others aposematic, aisthetic, or 

 even useful for purposes of mimicry, 1 have felt my attention 

 more and more attracted to many examples of coloration 

 which are inexplicable with reference to any one of the above- 

 stated uses. AVhy, for instance, are the fauces of many birds 

 so brilliantly tinted as to throw into the shade the glory of 

 their plumage?* W^hy are the yolks of the eggs of some 

 birds richly red, often in correspondence with a similar 

 painting of legs, bill, and fauces? Why do f both sexes of 

 80 many animals belonging to almost all branches of the 



• E. g. Kittiwake Gull (Rissa tridactijla). 

 t E. ij. Chougli { Pijrrhncorax (jrarul ux) . 



