46 ON ENTOMOLOGY. 



door forcibly opened by an intruder, she pulls it strongly inwards, and 

 even when half open often snatches it out of the hand ; but when she is 

 foiled in this, she retreats to the bottom of her den as her last resource. 

 The Rev. Revett Shepherd has often noticed in the fen ditches of Norfolk 

 a very large Spider (the species not yet determined), which actually forms 

 a raft for the purpose of obtaining its prey with more facility. Keep- 

 ing its station upon a ball of weeds about three inches in diameter, pro- 

 bably held together by slight silken cords, it is wafted along the surface 

 of the water upon this floating island, which it quits the moment it sees 

 a drowning insect. The booty thus seized, it devours at leisure upon 

 its raft, under which it retires when alarmed by any danger. That Spiders 

 may be able to breath under water, we can well understand from their 

 breathing like amphibious reptiles by means of gills, but there is an 

 aquatic spider (Argyroneta aquatica) which is not contented as a frog 

 would be with the air furnished by the water, but actually carries down 

 a supply of air from the atmosphere to her subaqueous nest. This 

 Spider does not like stagnant water, but prefers slow running streams 

 and ditches, where she may often be seen in the vicinity of London and 

 elsewhere, living in her diving bell, which shines through the water 

 like a little globe of silver, her singular economy was first described by 

 Clerck and De Geer. The shining appearance, says Clerck, proceeds 

 either from an inflated globule surrounding the abdomen, or from the 

 space between the body and the water. The Spider, when wishing to 

 inhale the air, rises to the surface with its body still submersed, and 

 only the part containing the spinneret rising just to the surface, when 

 it briskly opens and moves its four teats. A deep cone of hair keeps 

 the water from approaching or wetting the abdomen. It comes up for 

 air about four times an hour or oftener, though I have good reason to 

 suppose it can continue without it for several days together. " I found in 

 the middle of May," says Clerck, " one male and ten females, which I 

 put into a glass filled with water, where they lived together very quietly 

 for eight days. I put some duck weed (Lemna) into the glass to afford 

 them shelter, and the females began to stretch diagonal threads in a con- 

 fused manner from it to the sides of the glass, about half way down. 

 Each of the females afterwards fixed a close bag to the edge of the glass, 

 from which the water was expelled by the air from the spinneret, and 

 thus a cell was formed capable of containing the whole animal; Here 

 they remained quietly with their abdomens in their cells, and their 

 bodies still plunged in the water ; and in a short time brimstone coloured 

 bags of eggs appeared in each cell, filling it about a fourth part. On 

 the 7th July, several young ones swam out from one of the bags, all 

 this time the old ones had nothing to eat, and yet they never attacked 

 one another, as other Spiders would have been apt to do." 



I have now described some, though by no means all, of each order of 

 insects, and 1 shall conclude with some observation regarding it as a 



