326 ARACHNIDES. 



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 kw minutes. It is also cer- 

 tain that the bite of those large ones of South America, which are 

 there called Crab-Spiders, and are placed by us in the genus My- 

 gale, 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. 



Various insects of the genus Sphex, Lin,, (Wasps) seize upon 

 them, pierce them w^ith their sting, and transport them into holes 

 where they have deposited their eggs, as a source of food for their 

 young. Most of them perish in winter, but there are some which 

 live several years — such are the Mygales, the Lycosae, and probably 

 several others. 



M. Leon Dufour, who has published many excellent memoirs on 

 the anatomy of Insects, who has especially studied those of Valencia, 

 among which he has detected several new species, and to whose 

 labours the science of Botany is not less indebted, has paid particu- 

 lar attention to the respiratory organs of spiders, and it is from him 

 that we have taken our divisions, which consist of those that have 

 four pulmonary sacs — with as many external stigmata, two on each 

 side, and closely approximated — and of such as have but two. The 

 first, according to our method, form but the single genus 



Mygale. 



Their eyes always situated at the anterior extremity of the thorax, and usu- 

 ally closely approximated; feet and chelicerae robust. Most of them have 

 but four fusi(l), of which the two lateral or external, situated somewhat 



(1) Filieresy i. e. the papills or fusi through which the thread passes. 



