ON ARACHNIDA. 473 



fights to the death. It has been observed, that where this 

 theridion is most commou, a hymenopterous insect, known by 

 the trivial name of St. John's Jly, in all probability a sphex, 

 or pompilus, destroys a great number of them. The cocoon 

 is about the size of a hazel-nut, and the mother guards it with 

 the greatest assiduity. 



Degeer has observed another Theridion (aranea hipunc- 

 tuata of Linnaeus) spin round the insect arrested in its snare, 

 as well as all round the neighbourhood, fresh threads, drawing 

 them with its hinder feet, so as to hinder its prey from break- 

 ing its fetters, and then attack it wdth open force, kill it, and 

 drag it within its domicile ; this is usually in the cleft of a 

 casement. The angles, the corners of the walls which are 

 near it, are curtained with its web, which is loose and 

 spreading. 



The species of the genus Linyphia, the most common 

 (triangularis) sjjins on bushes, &c., particularly towards the 

 end of summer, a horizontal web, hung between the branches, 

 slender, not compact, and the extent of which, often consider- 

 able, varies in proportion to its proximity to, or distance from, 

 the points of attachment. To maintain it in the same situa- 

 tion, and prevent its sinking, it spreads above and on all sides, 

 perpendicular and oblique threads, which it fixes to the 

 branches in the neighbourhood. They are sometimes even so 

 drawn that the web becomes convex. It is suspended in the 

 midst of this very irregular assemblage of threads, being- 

 directed and crossing on all sides. The animal remains in an 

 inverted position, having the belly upwards and usually at 

 the centre of the web ; as soon as an insect is caught there, 

 it runs out quickly, pierces it with its mandibles through the 

 web, makes a rent there to allow it to pass, and without 

 enveloping it with silk, sucks the insect which is dead, or 

 excessively enfeebled by the effects of the poison. When 

 many individuals of this species are placed together, they 



