Pomona College, Clarcmont, California 135 
were taken out of the jar and soon scattered all over the labora- 
tory. They built their miniature orbs between the legs of chairs, 
on the lighting fixtures, on the microscopes and in e\-ery a\ailable 
place. They would place themsehes in the center of these small 
orbs and stay there all day. This action of the young is quite con- 
trary to that of the adult, who does not remain in the orb but in a 
hiding place near by. The young of .Irdinui cjciinna were found 
all o\-er the top of a rose fence in little webs. They made them 
in the top in order to get the greatest amount of light and sunshine. 
A family of Arauca was raised in the laboratory windows on the 
\ines. Fheir actions were not the same as the one raised indoors. 
They remained in a large clump swung from one of the branches 
of the vine and only on bright days did they scatter from this mass 
to return when the wind blew and it became cold. A hard rain 
storm came and all the spiders disappeared, but when the sun came 
out the spiders returned, making little orbs of their own, but did 
not go back into a mass. A great many of these little ones could 
not have survived the storm, but some must have remained under 
the leaves and started life anew as soon as it became warm. 
Certain conclusions can be drawn in connection with the shape 
of the egg case, the methods of emerging, and the actions upon 
emerging, of the immature spiders: 
1. All the egg cases of a certain species of spiders were found 
to be exactly the same. There were large numbers of the egg cases 
of Aranca collected, and none varied in either shape, texture, or 
method of building. The only variations found were in size and 
color. The colors varied from light to dark brown. 
2. The methods of emerging, the length of time and actions 
upon emerging \aried only according to the weather conditions and 
situations, so the same statement may apply to them as to the shape 
of the egg case. 
In a general collection a great many specimens taken are im- 
mature and very hard to determine on account of the undeveloped 
sexual organs, and the ilifferences in color pattern between the im- 
mature and its adult. It has been the aim of the writer to watch 
the changes in the color ile\ elopment and color pattern of certain 
well-known species of large families in order to find some way in 
