ON ARACHNIDA. 485 



of autumn, and a large species of scolopendva, are enemies 

 from which few of them escape. This scolopendra attacks the 

 largest tarantulas, and, after an obstinate combat, succeeds in 

 killing them, and taking possession of their habitation. The 

 two sexes live separately, and, except during the season of 

 reproduction, carry on a mortal warfare. This tarantula is 

 susceptible of anger to an extreme degi'ee, especially when 

 forced to quit its habitation, which it never does without a 

 desperate struggle. 



In the genus Salticus, the species named Aranea scenica 

 by Linnaeus is very common, and remains generally on walls 

 exposed to the sun, or on the glasses of casements, where it 

 parades at all hours during the summer. It walks, as it were, 

 by jerks, stopping short altogether after having gone some 

 paces. It rises on its first feet, elevates the anterior part of 

 its body, to consider on which side it shall leap ; and it is 

 thus that it seizes small insects, especially gnats, which it 

 appears to prefer. When it has discovered the object of its 

 prey, it approaches it softly, with gentle steps, until it comes 

 to a distance which it can cross by a single jump, and fall 

 upon the little animal which it has been watching. It does 

 not fear to leap perpendicularly from a wall, because it always 

 finds itself attached by a thread of silk, which it continually 

 unwinds in walking, and which, under these circumstances, 

 holds it suspended. The other species of Saltici also use the 

 same precaution when they fall, either of their own accord or 

 from some sudden impulse ; and this thread serves the pur- 

 pose, being moved by the wind, to transport them with facility 

 from one place to another. They can also re-ascend to the 

 point from whence they had descended. 



Some individuals of the species above mentioned, and which 

 Degeer kept in a box, spun against the walls little nests in the 

 form of oval or rounded sacs, composed of white silk, and 

 pierced on both sides with an aperture. Lister says that this 



