SPIDERS AND MITES 



matchless achievements in thread. And still their indus- 

 trious art is plied everywhere around us in our chambers, 

 in our windows, in our cellars, in our walls, in our gar- 

 dens, in waste and desert places, and even under water. 

 But you shall hear what Professor Owen says on the de- 

 gree and mode in which Spiders exercise their singular 

 secreting faculty, which " varies considerably in the differ- 

 ent species. Some, as the Clubionce, line with silk a con- 

 ical or cylindrical retreat, formed, perhaps, of a coiled-up 

 leaf, and having an outlet at both extremities, from one of 

 which may issue threads to entrap their prey. Others, as 

 the Segestrice, fabricate a silken burrow of five or six inches 

 in length, in the cleft of an old wall. The Mygale cemen- 

 taria lines a subterraneous burrow with the same sub- 

 stance, and manufactures a close-fitting trap-door of ce- 

 mented earth, lined with silk, and so attached to the entry 

 of the burrow as to fall down and cover it by its own 

 weight, and which the inmate can keep close shut by 

 means of strong attached threads. 



"The arrangement of Spiders by M. Walckenaer into 

 families, characterized by their habits, places the principal 

 varieties of their webs in a very concise point of view. 



"The Cur sores, Saltatores, and Laterigradce, make no 

 webs: the first catch their prey by swift pursuit; the sec- 

 ond spring upon their prey by insidious and agile leaps; 

 the third run, crab-like, sidewise or backward, and occa- 

 sionally throw out adhesive threads to entrap their prey. 

 The Latebricolce hide in burrows in fissures, which they line 

 with a web. The Tubicolce enclose themselves in a silken 

 tube, strengthened externally by leaves or other foreign 

 substances. The Niditelce weave a nest whence issue threads 



to entrap their prey. The Filitelce are remarkable for the 



-SCIENCE 11 



