ADIPOSE SEOEETIONS. 
47 
Spherical bodies which freely roll about on any smooth 
surface. 
If one of these vesicles— ^all of which glitter- like 
white sand grains— be placed on a slip of glass and 
breathed upon, it immediately falls into a drop , of 
moisture, without showing a trace of any organization. 
They look exactly like ova, but are not such. These 
globules are fecal matter, discharged from the anus of 
the insects, which swarm within the curled leaves, and 
their spherical form is due to the presence of the 
fine meal-like powder taken from the bodies of the 
Aphides, and which gives a character repellant of 
moisture to these globules. 
By this peculiar dusting of their surfaces the 
insects are not incommoded by their own excreta, 
for the liquid refuses to soil what it touches, just as 
drops of dew will run ofi* the glaucous coat of a 
cabbage leaf. 
It is possible that the hoariness of some species 
may be a protection to them from rain very much in 
the same manner. The globular granules above 
noticed may be seen also in the tangled purses made 
by CryptosipJmm silenes and likewise in other close 
habitations of Aphides. 
References will be made elsewhere to those chemical 
characters which can be traced in such Aphis secre- 
tions as can be secured for examination. Necessarily 
these quantities must be smnll in amount. 
