446 PACKARD^ORIGIN OF MARKINGS OF ORGANISMS. [Dec. 2, 



a color wheel the stripes remained distinct, not blending. When 

 the speed was increased to a degree evidently exceeding that of the 

 animal in its swiftest movements, it formed a dark grayish-brown, 

 almost black ring, and the stripes were nearly if not wholly blended, 

 certainly enough so to render the animal inconspicuous. ' One 

 would expect that as the ground color of the chipmunk is a russet 

 or reddish-brown the ring would be russet or reddish-brown, but 

 this was not the case. 



The animal was then placed on its side and so attached to the 

 white disk that the subdorsal whitish stripe was visible, and also the 

 upper portion of the light under side of the body. On rapidly 

 revolving the disk the lighter and darker portions of the chipmunk 

 still remained somewhat distinct, not perfectly blending. The 

 result was a blurred, confused mass lighter on the under side and 

 darker along the back. 



The experiment was not so satisfactory as those with the zebra 

 markings, and it is hoped that some one will make further experi- 

 ments. The direction of rotation was parallel with that of the 

 striped body of the chipmunk. There are in this animal no trans- 

 verse bars, hence the stripes do not so readily blend. Moreover 

 the body of the animal in running is more or less unsteady, undu- 

 lating or arched. Until further observations are made we would 

 provisionally conclude that the stripes of the chipmunk remain dis- 

 tinct when the animal is slowly running, but that they become 

 blurred or confused when the creature is darting off at its greatest 

 speed. 



2 1. PCECILOGENV IN PALEOZOIC TiMES. 



In claiming that all Miillerian mimicry is due to the attacks of 

 birds, one would do well to bear in mind that a number of 

 paleozoic net-veined insects had wings which were banded or 

 spotted, and that these insects lived at a period when modern liz- 

 ards, much less birds, did not exist. It may therefore be inferred 

 that these markings originated from the simple action of physical 

 and physiological causes, irrespective of the biological environment, 

 such as the attacks of insectivorous animals, unless they suffered 

 from the desultory warfare waged by the small active terrestrial 

 labyrinthodents, such as the Hyalonema, etc., of the Upper 

 Carboniferous period of Nova Scotia. 



If we examine the works of Brongniart and of Scudder on fossil 

 insects it becomes apparent that pcecilogeny was an active process as 



