ON AERONAUTIC SPIDERS, 275 
the extreme points of the head and abdomen, +5 inch 
across the broadest part of the abdomen, and 
weighed about a quarter of a grain. The largest 
individuals of the second species seen floating in 
the air were of somewhat inferior weight and di- 
mensions. 
Aéronautic Spiders, properly so called, or those 
species which by éxstinctively employing their lines to 
sail in the atmosphere greatly facilitate and extend 
their geographical distribution, will probably be 
found chiefly among such as are active during the 
day and erratic. Numerous facts tend to corro- 
borate this idea, the correctness or inaccuracy of 
which can only be determined by more extended 
observations. 
vu Dy) 
