how Spiders effect their aerial Excursions. 459 



longer than the posterior ones ; and it moves in a hiteral direc- 

 tion with almost as much ease and expedition as it does straight 

 forward. The largest individuals of this species observed to be 

 conveyed through the atmosphere by a current of air acting 

 upon their lines, measured ^th of an inch between the extreme 

 points of the head and abdomen ; -fVth of an inch across the 

 broadest part of the abdomen ; and weighed about a quarter of 

 a grain. 



The second species has also four eyes of a greater magnitude 

 than the other four. The arrangement and relative size of three 

 pair placed in the fore-part of the head may be thus expressed 

 by dots '...: ; one of the other pair of large eyes being situated 

 on each side of the head. Spiders of this species have the last 

 pair of legs longer than the first, and move with great celerity, 

 but rarely in a lateral direction. They vary considerably in 

 colour, some being of a much darker hue than others, and these 

 are frequently without the pale longitudinal line which extends 

 the whole length of the thorax, and sometimes even on to the 

 abdomen of the lighter-coloured specimens. The largest indi- 

 viduals seen floating in the air were somewhat inferior in weight 

 and diuiensions to the largest of the preceding species observed 

 under similar circumstances*. 



* [s this the Aiaiicu doiHilis of the Si/stema Xatitrcc, Gmeliii's edit.r 



XXI. De 



