224 Isabel McCracken 



tending to produce this variant, certainly more individuals v^ould 

 have shown the effect. 



The numerical results in second, third and fourth generations 

 of the occurrence of the sport might have been different had con- 

 tinued breeding of the progen}^ of the first B parents been carried 

 on and if a larger number of broods had been reared from each 

 pair. 



There was found to be no greater likelihood of the recurrence of 

 a sport in a brood from parents in^whose lineage sports had pre- 

 viously occurred than in broods from parents in whose lineage no 

 such sports were known to have occurred in so far as this point 

 was tested. Numerous matings were made between individuals 

 having AB sisters or brothers, but in no case was there a recur- 

 rence of the AB character. 



That the sport is of occasional occurrence in the field has already 

 been noted. The stable character of many sports or aberrant 

 variations in animals such as this appears to be is undoubted, 

 since it has been shown several times, notably in the race of Ancon 

 sheep from a single short-legged, long-backed ram, in 1791, and 

 the production of the Mauchamp-merino breed of sheep in 1828 

 from a single ram with long, smooth, silky wool.- Also more 

 recently the production of a race of polled Hereford cattle in 

 Kansas in 1889 from a single polled buU.^ 



The main purpose of the present investigation was to deter- 

 mine, in case the new character should be found to be stable, its 

 hereditary value in relation to the characters of the parent species. 

 The hereditary value of each of the dichromatic extremes with 

 relation to the alternative extreme had been previously deter- 

 mined.^ 



To test the hereditary value of the Melasoma sport, the first two 

 sports occurring simultaneously in the first generation were used 

 as parents for succeeding generations. Other sports were mated 

 with the parent forms. 



^Darwin, 1868, Animals and Plants, vol. i, p. 126. 

 'Guthrie, 1906, Proc. Amer. Breeders Assoc, vol. ii, p. 93. 



''McCracken, 1906, Inheritance of Dichromatism in I.ina lapponica. The Journal of Experimental 

 Zoology, vol. iii, pp. 320, 336. 



