32O H. H. NEWMAN. 



served both in aquaria and under natural conditions. In the open, 

 excited males were often seen to be in rapid pursuit of the females, 

 succeeding occasionally in cornering and clasping them. The 

 pursuit of the males was often so impetuous that the females were 

 entirely frightened away. The coyness on the part of the females 

 acts as an excitant on the males. 



Rivalry among the males is very keen and as a rule those 

 whose "spawning plumage" is most brilliant succeed in driving 

 away all competitors. I have observed under normal conditions 

 that a certain male, always the most brilliantly colored one in the 

 neighborhood, seems to control the situation, driving away all 

 males that attempt to encroach upon his territory. The size of 

 the male seems to be a much less important factor in determining 

 his success than is the degree of sexual maturity as indicated by 

 the brilliance of his coloration, for I have often seen a male of 

 comparatively small size put to rout several others of twice or 

 three times his size, such is the impetuosity of his attack. I 

 was able to observe this rivalry to better advantage in aquaria 

 where it was possible to identify the various individuals and thus 

 to keep an accurate record of the success or failure of each male. 

 The following record was made on June 20, 1906. 



A fresh lot of F. heteroditus was placed in the aquarium early 

 in the morning. At about ten o'clock in the forenoon they were 

 observed to be actively spawning. About twenty females were 

 spawning on the bottom of the aquarium on the side away from 

 the light. Seven males seemed ready to take part in the process, 

 but one very large male, more brilliantly colored than the rest, 

 continually drove away all other males that attempted to spawn. 

 So solicitous was he about driving off his competitors that he 

 could scarcely attend to all of the females that were ready to 

 spawn. While the ruling male was engaged in clasping one 

 female another male in a remote portion of the aquarium would 

 occasionally succeed in spawning with another female. When- 

 ever such an occurrence was observed by the ruling male, he 

 always gave chase and invariably routed the intruder. This male 

 was so much larger and more vigorous than any of the others 

 that none dared to dispute his authority to the extent of offering 

 battle. For purposes of experiment I removed this male from 



