48 r. M. CAMPBELL — OBSEEVATIOXS ON SPIDERS. 



wliile in dry weather many species are to be obtained by carefully 

 searching the grass growing by the water-side. As a rule those 

 frequenting damp places soon die in confinement, while otlna's 

 have been known to live some months without water or even food. 



Spiders are best caught in a glass tube (about 2^ inches by ^ an 

 inch), and the small species by applying to them a wotted finger. 

 A knowledge of their habits, a quick eye, and a ready hand, are 

 required, especially for some fast runners, but it is astonishing 

 how soon even these become tired out. They are all best pre- 

 served in spirit (about 40 per cent, over proof). 



It is interesting to observe the difference between the spinning 

 organs of the larvae of Lepidoptera and those of spiders. The com- 

 paratively large single opening of the former causes the viscid 

 fluid to dry but slowly, thus preventing the silk from being 

 employed in connexion with any rapid movement, while the spider 

 with its number of tubes (already described), exposes to the 

 atmosphere as many minute liquid jets. These almost instanta- 

 neously solidify as they unite, thus permitting that immediate use 

 of the thread which is so necessary to the spider for its safety or 

 means of subsistence. 



The thread varies in thickness from — o~do- to ^-^^oo of an inch in 

 diameter, and yet will sustain a weight of from 66 to 60 grains. 

 Many have been the attempts to use it in manufacture. Tlie first 

 was by Bon, who wove gloves made from the silk of cocoons at the 

 commencement of the last century,* and in 1710 the Academy of 

 Sciences in Paris charged Reaumur to investigate the subject. His 

 report was unfavourable.! Eighty years afterwards Tremeyer (in 

 Italy) drew the silk straight from the Epeira diadema, with which 

 he also made gloves, and about the beginning of this century 

 Troughton employed it in scientific instruments, instead of silver 

 wire. Further experiments have within the last few years been 

 made by Dr. Wilder, who gives their result in the ' Galaxy ' (July, 

 1869). He shows that it is quite possible to obtain sufficient 

 spiders' thread or silk for it to become a material of general 

 manufacture. He reeled 150 yards from a NepMla plumipes, on 

 twenty occasions within a month, and he calculates that it would 

 require a similar produce, from 450 of this species, that is, 

 1,350,000 yards, to make a yard of silk such as would be used in 

 a dress. Greater labour is however required than in the case of 

 the silk from the Bomhj/x, and this, notwithstanding a finer texture, 

 is an insuperable objection to its use. 



* Bon, ' Dissertation sur I'Arai.fj^nee.' — 1710. 



t "Examen siir les Araignes," in the ' Report of the Academy of Sciences.' 

 —1710. 



