308 ARACHNIDES. 



by the reflection of light after sunrise. By chemical analysis, these threads 

 exhibit the same characters as the web of the spider : they are not then formed 

 in the atmosphere, as, for want of proper observation, ex visu, that celebrated 

 naturalist, M. Lamarck, has conjectured. Gloves and stockings have been made 

 with this silk; but it was found impossible to apply the process on a large 

 scale, and as it is subject to many difficulties, is rather a matter of curiosity 

 than utility. This substance, however, is of much greater importance to the 

 little animal in question. With it, the sedentary species, or those which do 

 not roam abroad in search of their prey, weave webs of a more or less compact 

 tissue, whose form and position vary according to the peculiar habits of each 

 of them, and that are so many snares or traps, where the insects on which they 

 feed become entangled, or are taken. No sooner is one of them arrested there 

 by the hooks of its tarsi, than the Spider, sometimes placed in the centre of his 

 net, or at the bottom of his web, or at others lying in ambush in a peculiar 

 domicil situated near and in one of the angles, rushes towards his victim and 

 endeavours to pierce him with his murderous dart, distilling into the wound a 

 prompt and mortal poison ; should the former resist too vigorously, or should 

 it be dangerous to the latter to approach it, he retreats, waiting until it has 

 either exhausted its powers by struggling, or become more entangled in the 

 net ; but should there be no cause of fear, he hastens to bind it by involving 

 the body in his silken threads, with which it is sometimes completely 

 enveloped. 



Lister says that Spiders dart their threads in the same way that the Porcu- 

 pine darts his quills, with this difference, however, that in the latter, according 

 to the popular belief, the spines are detached from the body, whereas in the 

 former, these threads, though propelled to a considerable distance, always 

 remain connected with it. The possibility of this has been denied. Be it as 

 it may, we have seen threads issuing from the mamillse of several Thomisi form 

 straight lines, and when the animals moved circularly, producing moveable 

 radii. A second use to which this silk is applied by all female Araneides, is in 

 the construction of the sacs destined to contain their eggs. The texture and 

 form of these sacs are variously modified, according to the habits of the race. 

 They are usually spheroidal; some of them resemble a cap or tymbal, others 

 are placed on a pedicle, and some are claviform. They are sometimes partially 

 enveloped with foreign bodies, such as earth, leaves, &c.; a finer material, or 

 sort of tow or down, frequently surrounds the eggs in their interior, where 

 they are free or agglutinated and more or less numerous. 



I have ascertained that a single wound from a moderate sized spider will 

 kill our common Fly in a few minutes. It is also certain that the bite of those 

 large ones of South America, which are there called Crab-Spiders, and are 

 placed by us in the genus Mygale, kills the smaller vertebrated animals, such 

 as Humming-Birds, Pigeons, &c., and produces a violent fever in Man; the 

 sting of some species in the south of France has even occasionally proved fatal. 

 We may, therefore, without believing all the fabulous stories of Baglivi and 

 others respecting the bite of the Tarantula, mistrust Spiders, and particularly 

 the larger ones. 



