MOTIONS OF INSECTS. 317 
suddenly like a tiger.—Bartram observed one of these 
spiders that jumped two feet upon a humble-bee. The 
most amusing account, however, of the motions of these 
animals is given by the celebrated Evelyn in his Travels. 
‘When at Rome, he often observed a spider of this kind 
hunting the flies which alighted upon a rail on which 
was its station. It kept crawling under the rail till it 
arrived at the part opposite to the fly, when stealing up 
it would attempt to leap upon it. If it discovered that 
it was not perfectly opposite, it would immediately slide 
down again unobserved, and at the next attempt would 
come directly upon the fly’s back. Did the fly happen 
not to be within a leap, it would move towards it so 
softly, that its motion seemed not more perceptible than 
that of the shadow of the gnomon ofa dial. If the in- 
tended prey moved, the spider would keep pace with it 
as exactly as if they were actuated by one spirit, moving 
backwards, forwards, or on each side without turning. 
When the fly took wing, and pitched itself behind the 
huntress, she turned round with the swiftness of thought, 
and always kept her head towards it, though to all ap- 
pearance as immoveable as one of the nails driven into 
the wood on which was her station: till at last, being 
arrived within due distance, swift as lightning she made 
the fatal leap and secured her prey?. I have had an 
opportunity of observing very similar proceedings in 
Salticus scenicus, Latr. 
But the legs of insects are not the only organs by 
which they leap. The numerous species of the elastic 
beetles (Elater, L.), skip-jacks as some call them, pers 
a Eyelyn, quoted in Hooke’s Microgr. 200— 
