LETTERS ON ENTOMOLOGY. 153 
She also leaves a little edge or groove, just within 
the entrance, upon which the door closes, and 
fits with the greatest precision. If the door is 
a little raised, the observer immediately feels a 
strong resistance, which is the spider pulling 
with all her might to keep it close ; but when 
she finds it in vain, she runs off. If the door is 
fastened down, there will be a new door the next 
morning. This singular habitation is merely an 
abode for the spider, which hunts in the night, 
and carries the prey to devour at leisure at the 
bottom of her den, where the remains are often 
found. This species is not uncommon in the 
south of France. 
We must not pass over the aquatic spider, 
who builds her enchanted airy palace under the 
water. First she spins loose threads, in various 
directions, attached to the leaves of aquatic 
plants, and spreads over them a transparent 
varnish, which issues from the middle of her 
spinners, and is so extremely elastic, that if a 
hole be made, it instantly closes again. Next she 
spreads over her belly a pellicle of the same, and 
ascends to the surface ; it is not exactly known 
how she conveys a bubble of air under this 
pellicle, but it is supposed that she draws it in, 
and pumps it out, from an opening in the middle 
